add semantic paper

fix parser and semantic v2.2
fix parse and semantic v2.1
2025-12-05 02:29:14 +09:00 · 2025-12-05 02:09:12 +09:00 · 2025-12-05 00:47:51 +09:00 · 2025-12-03 04:58:41 +09:00 · 2025-12-03 01:57:47 +09:00 · 2025-12-03 01:53:05 +09:00
63 changed files with 11037 additions and 910 deletions
--- a/.crossnote/config.js
+++ b/.crossnote/config.js
@@ -0,0 +1,15 @@
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+++ b/.crossnote/head.html
@@ -0,0 +1,6 @@
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--- a/.crossnote/parser.js
+++ b/.crossnote/parser.js
@@ -0,0 +1,12 @@
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--- a/.crossnote/style.less
+++ b/.crossnote/style.less
@@ -0,0 +1,48 @@
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--- a/.gitattributes
+++ b/.gitattributes
@@ -1,3 +0,0 @@
 [attr]lfs-file filter=lfs diff=lfs merge=lfs -text
 *.pdf lfs-file
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,7 @@
 .idea
-.vscode
+.vscode
 *.o
 *.yy.c
 node_modules
--- a/build.js
+++ b/build.js
@@ -0,0 +1,28 @@
 const { Notebook } = require("crossnote");
 const path = require("path");
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 main();
--- a/notes/1.md
+++ b/notes/1.md
@@ -1,9 +1,41 @@
-컴파일러 1
+# ISA & Compiler Basics
-===
+
 ## Basic Computer
 To get a task done by a general-purpose computer, we need:
 * Program: A sequence of instructions
 * Instruction set: A set of possible instructions
 ### Von Neuman Architecture
 Both Instructions and data are stored in the memory.
 Instructions dictate:
 1. which and how data are manipulated
 2. which instruction should be next
 The memory is independent of the CPU.
-# Interpreter in Modern Processors
+### How to load a program
 ```
 *.c -(compiler)-> *.s: Assembly program
 *.s -(assembler)-> *.o: Object file 
 *.o -(linker)-[with library(*.o)]-> *.exe: Executable
 *.exe -(loader)-> to in memory 
 ```
 ### Program
 Computer is essentially a complex state machine.
 **programmer visible state**:
 * Memory
 * Registers
 * Program Counter
 Instructions(Program) specify how to transform the values of programmer visible state.
 # Compiler
--- a/notes/2.md
+++ b/notes/2.md
@@ -1,5 +1,4 @@
-Lexical Analysis
+# Lexical Analysis
 ===
 포트란은 모든 whitespace를 지움.
@@ -117,4 +116,7 @@ main() {
 ### Handwork
 * Thompson's construction (RE -> NFA)
-* Subset Construction(NFA -> DFA)
+* Subset Construction(NFA -> DFA)
 DFA Optimization
--- a/notes/3.md
+++ b/notes/3.md
@@ -0,0 +1,328 @@
 # Syntax Analysis
 ## Specification
 ### Context-Free Grammars (CFG)
 There are four main compoennts of CFG
 * Terminal Symbols
 * Non-terminal Symbols
 * Start Symbol $S$
 * Production
 Language generated by a CFG is a set of strings of terminals by repeatedly applying productions to the non-terminals: $L(G)$ indicates a language generated by the grammar $G$.
 We can use CFGs to express the syntax of the target programming languages: Parser detects that the token stream from lexer is valid or invalid.
 **We cannot rely on regex to sepcify the syntax:** Because regex is not expressive enough to describe valid syntax. (e.g. nested parenthesis)
 ## Recognition
 ### Parse Tree
 A tree representation of the derivation.
 parse tree has `terminals` at the leaves, `non-terminals` at the interior.
 An in-order traversal of the leaves is the original input.
 We can appply productions for the non-terminals in any order:
 * leftmost derivation
 * rightmost derivation
 #### Ambiguity
 A grammar $G$ is ambigous if it produces different parse tree depening on the order.
 It should be **resolved** to construct a useful parser.
 **removing ambiguity**
 Example of Ambiguity.
 1. Precedence:
 The production at higher levels will have operators with lower priorities (and vice versa).
 we can insert non-terminals to enforce precendence.
 2. Associativity:
 We should determine where to place recursion depending on the associativity.
   * left associative: place the recursion on the left
   ```txt
   S -> S - T | T
   T -> id
   ```
   * right associative: place the recursion on the right
   ```txt
   S -> T ^ S | T
   T -> id
   ```
   * non associative: do not use recursion
   ```txt
   S -> A < A | A
   A -> id
   ```
 ### AST (Abstract Syntax Tree)
 AST discards unneeded information for syntax analysis: removes non-terminals from parse tree.
 ### Error Handling
 One of the purposes of the compiler is error handling.
 - to detect non-valid programs
 - and to translate the non-valid to the valid
 so therefore, error handler should:
 * report errors accurately and clearly
 * recover quickly from an error
 * not slow down compilation of valid code
 so Why?
 * back in the day, the compiler was extremely slow.
 * but nowadays, we do not need complex error handling procedure
  * Quick recompilatio
  * Users tend to correct few errors at once
  * Does not need a complex error recovery procedure
 ## Automation
 How to generate parse tree from CFG?
 ### Top-Down Parsing
 Construct a leftmost derivation of string while reading the token stream.
 e.g.
 ```txt
 S -> E + S | E
 E -> num | (S)
 ```
 We can implment it as **recursive descent parsing**.
 Recursive descent parsing is try out rules in order and backtrack if the production does not generate proper token.
 #### Predictive Parsing and LL(1)
 But it needs **backtracking**.
 So we introduce **predictive parsing**.
 Predictive Parsing applies a single production without "backtracking". LL(1) grammar can apply **"at most a single production"**, which actually eliminates the multiple matches in top-down parsing(recursive-descent).
 ### Parser Implementation
 #### Recursive Descent Parser by LL(1)
 ```text
 S -> ES'
 S' -> +ES' | e
 E -> num | (S)
 ```
 We can use the table to implement parsers.
 | *   | num | +   | (   | )   | $(EOF) |
 | --- | --- | --- | --- | --- | ------ |
 | S   | ES_ |     | ES_ |     |        |
 | S_  |     | + S |     | e   | e      |
 | E   | num |     | (S) |     |        |
 ```c
 void parse_S() {
    switch(token) {
        case num: parse_E(); parse_S_(); return;
        case '(': parse_E(); parse_S_(); return;
        default: ParseError();
    }
 }
 void parse_S_() {
    switch(token) {
        case '+': token=input.next(); parse_S_(); return;
        case ')': return;
        case EOF: return;
        default: ParseError();
    }
 }
 void parse_E() {
    switch(token) {
        case num: token = input.next(); return;
        case '(': token = input.next(); parse_S(); if(token != ')') ParseError(); token = input.next(); return;
        default: ParseError();
    }
 }
 ```
 #### Parsing Tables
 And then How to Construct a Parsing Tables? There are three important traits to gen parse tables.
 * $x$ is nullable if it can derive an empty string.
 * $\text{First}(x)$ is a set of terminals that can derived in the first position.
 * $\text{Follow}(x)$ is a set of terminals that can appears after $\alpha$ in at least one of the derivations.
 Computing Nullable
 1. Easy
 Computing First
 1. $\text{First}(t) = \set{t}$
 2. For a production $x \to A_1 A_2 \dots A_n$ where $A_1 \dots A_{i-1}$ are nullable, then $\text{First}(x) += \text{First}(A_{i})$
 Computing Follow
 1. $\text{Follow}(S) = \set{ \$ }$, ($S$ is the start symbol)
 2. For a production $x \to A_1 A_2 \dots A_n$ where $A_{i+1}\dots A_{n}$ are nullable, then $\text{Follow}(A_{i}) += \text{Follow}(x)$
 3. For a production $x \to A_1 A_2 \dots A_n$ where $A_{i+1}A_{i+2}\dots A_{j-1}$ are nullable, $\text{Follow}(A_{i}) += \text{Follow}(A_{j})$
 So Combine Them Together:
 ```py
 S = symbols.start
 for x in symbols:
    First(x) = {}; Follow(x) = {}, Nullable(x) = false
 Follow(S) = {$}
 for t in terminals:
    First(t) = {t}
 Nullable(e) = True
 while not (First.is_changed or Follow.is_changed or Nullable.is_changed):
    for X, A in productions:
        if all(A) is Nullable: Nullalbe(X) = True
        if A[1..i-1] is Nullable: First(X) += First(A[i])
        if A[i+1..n] is Nullable: Follow(A[i]) += Follow(X)
        if A[i+1..j-1] is Nullable: Follow(A[i]) += First(A[j])
 ```
 We can use the tables with `First`, `Follow`, `Nullable` to make actual **Parsing Tables** by combining.
 ### Bottom-Up Parsing
 Bottom-up Parsing is more efficient than Top-down parsing by using **LR grammars**, which means **L**eft-recursive grammars, and **R**ight-most derivation.
 It relies on **Shift-reduce Parsers**.
 Shift-Reducing Parsing:
 Bottom-up parser traces a rightmost derivation in reverse, we should scan the input terminals in a left-to-right manner.
 So the parser splits a string into two parts: sequence of symbols to reduce(**stack**), remaining tokens(**input**).
 And shift-reduce parsing requires two actions: **Reduce**, **Shift**.
 What's the important challenge is "Action Selection Problem":
 As there can be conflicts: For a given state(stack + input) there can be multiple possible actions:
 * shift-reduce conflict
 * reduce-reduce conflict
 ### LR Grammars
 * LR(k): left-to-right scanning, right most derivation and $k$ symbol lookahead
 * LR(0) Grammar
 LR(0) indicates grammars that can determine actions without any lookahead.
 There are **no reduce-reduce and shift-reduce conflicts**, because it should be determined by stacks.
 ### NFA Representations
 We can represent shift-reduce parsing using an **NFA**, whose states are production with separator '`.`' on RHS. And we have an additional dummy production `S' -> S$` for a start and end state.
 There are two types of transitions between the states:
 * **shift transition**: transition by the shift actions.
 * **$\epsilon$ transition**: that is the parser expand the expected list not consuming any input tokens. (transition to LHS of the production is equal to next of the current position)
 #### NFA to DFA
 NFA can be fully converted to DFA. by using DFA, the parser determine whether to shift or reduce: by using symbols in the stack to **traverse the state** and **determine whether to shift or reduce by destination state**.
 ### Parsing Table And LR(0)
 DFA Traversal is implemented by simplifying DFA to **LR Parsing Table**.
 Store the states along with the symbols in the stack: <`symbol`, `state`>
 There are two different types of tables: `goto`, `action`.
 * `goto`: determine the next state using the top state and an **input non-terminal**.
 * `action`: determine the action using the top state and an input terminal.
 And table consists of four different actions:
 * `shift x`: push<a, x> on the stack (a is current input and x is a state)
 * `reduce x -> a`: pop a from the stack and push <`x`, `goto[curr_state, x]`>
 * accept(`S' -> S$.`) / Error
 Also DFA states are converted to index of each rows.
 But There is a limitation when there are multiple options to fill the parsing table, which should be solved with **lookahead**.
 ### SLR(1) Parsing
 A simple extension of LR(0).
 For each reduction `X -> b`, look at the next symbol `c` and then apply reduction **only if `c` is in `Follow(X)`** which is a lookahead.
 ### LR(1) Parsing 
 LR(1) uses lookahead more delicately. For them, it uses a more complex state like `X -> a.b,c`, which means:
 1. `a` is already matched at top of the stack
 2. next expect to see `b` followed by `c`
 Also `X -> a.b,{x1,x2,...,xn}` indicates:
 * forall i in `{x1,...,xn}`, `X -> a.b,i`
 We extend the $\epsilon$-closure and `goto` operation.
 LR(1) closure identification:
 * start with `Closure(S) = S`
 * foreach item: `[X -> a.Bb,c]` in `S`
  * add `{B -> .y,First(bc)}`
 * Initalize the state with `[S' -> .S,$]`
 LR(1) `goto`:
 Given an Item in the state I: `[X -> a.Bb,c]`, `Goto/Shift(I, B) = Closure([X -> aB.b,c])`
 LR(1) Parsing Table is same as LR(0) except for **reductions**.
 ### LALR(1) Parsing
 LR(1) has too many states. LALR(1) Parsing.
 LR(1) parsing is a **LookAhead LR**.
 Construct LR(1) DFA and merges any two LR(1) states whose items have the same production rule, but different lookahead. It reduces the number of parser table entries, but theoretically less powerful than LR(1).
 LR(1) generally has the same number of states as SLR(1) but much less than LR(1).
 But we will not dive into the details of LALR(1).
 ### LL/LR Grammars
 1. LL Parsing Tables
   * Table[NT, T] = Production to apply
   * Compute using First, Follow.
 2. LR Parsing Tables
   * Table[LR State, Term] = shift/reduce/error/accept
   * Table[LR State, NT] = goto/err
   * Computing using closure and goto operations on LR states
 ## Automatic Disambiguation
 It is highly complex to propose unambiguous grammars: precedence, associativity. By defining precedence, using ambiguous grammars without shift-reduce conflicts: define precedence between terminals on the stack vs. terminals on the input.
 ## AST Data Structure
 LL/LR parsing implicitly build AST.
 * LL parsing: AST represented by the productions
 * LR parsing: AST represented by the reduction
 ### AST Construction in LL
 ```cpp
 expr parse_S() {
    switch (token) {
        case num:
        case '(':
            expr child1 = parse_E();
            expr child2 = parse_S_();
            return new S(child1, child2);
        default: ParseError();
    }
 }
 ```
 ### AST Construction in LR
 Construction mechanism:
 * Store parts of the tree on the stack
 * foreach nonterminal `X` on the stack, store the sub-tree for `X`
 * After reduce operation for a production `X -> a`, create an AST node for `X`
--- a/notes/4.md
+++ b/notes/4.md
@@ -0,0 +1,144 @@
 # Semantic Analysis
 Even after passing the lexical and syntax analysis, there are still erros: correct usage of variables, objects, functions.
 **Semantic Analysis** ensures that the program satisfies a set of rules regarding the usage of programming constructs.
 There are two main categories of semantic analysis:
 * Scopes
 * Types
 ## Scope
 Lexical scope is textual region in the program.
 Scope of an identifier is the lexical scope its declaration refers to
 ### Symbol Tables
 Symantic checks refer to properties of identifier in the program; it need an environment to store identifier info: **symbol table**.
 In symbol tables each entry contains name of an identifier and additional info.
 ### Implementing Symbol Tables
 Five operations:
 * `Insert Scope`
 * `Exit Scope`
 * `Find Symbol(x)`
 * `Add Symbol(x)`
 * `Check Scope(x)`
 We can build the symbol tables during parsing or after constructing the AST. The symbol tables should be generated before semantic analysis.
 ### Function Declaration and Usage Types
 * Declare the functions before usage(`cminus`)
 * Can use functions before declaration(`py`)
 * Separate body declaration(`C`)
 ### Scope Analysis
 * Generate Symbol Table and do Scope Analysis
 * Simultaneously
 ## Types
 * Type Checking: A set of rules which ensures the type consistency of different construct in the program.
 * Type inferencing: fill missing type info.
 ### Type Checking
 Semantic checking to enforce the type safety of the program.
 There are three types of types.
 * Statically typed
 * Dynamically typed
 * Untyped
 Static Type Checking does not require additional type checking instructions at runtime. It guarantees that the executions are safe at compile time. But modern languages require both static and dynamic type checking (union, void pointer).
 A **type** is a description of a set of values and a set of allowed operations on those values.
 **Type expression** is the description the possible types in the program.
 **Type System** defines types for language construct like nodes in AST.
 Language usually have basic types aka primitive types. Using these types to build type expressions.
 ### Type Comparison Implementation
 There are two options:
 1. Implement a method `Equals(T1, T2)`.
 It must compare type trees of T1 and T2. For OOP languages also need sub-types
 ### Type Checking Methodology
 Type checking means verifying whether expressions are given proper types
 1. Implement using Syntax-Directed Definitions(SDD)
 2. First build the AST, then implement type checking by recursive traversal of the AST nodes
 #### SDD
 SDD associates semantic rules for the productions in the CFG. It checks types based on the semantic rules associated with the production rules.
 #### AST Traversal
 Type Checking During AST Traversal.
 중간에 새로운 타입이 생길 수 있음.
 By Recursive Traversal of the AST nodes, inferencing types of AST nodes.
 ### Inference
 $$\frac{\vdash H_1 \vdash H_2 \vdash H_3}{\vdash \text{conclusion}}[\text{rule name}]$$
 #### Soundness
 항상 참이 되는 타입
 $e : T$ means that $e$ is a sound expression of type $T$, that is $e$ is always the type $T$.
 for non expression statements use special unit type (like void or empty type)
 $S: \text{void}$
 #### Proof Tree
 $$\frac{
  \frac{1 \text{ is a integer literal}}{\vdash 1: \text{int}} [\text{int}] \;
  \frac{2 \text{ is an integer literal}}{\vdash 2: \text{int}} [\text{int}]
  }{\vdash 1 + 2 : \text{int}} [\text{int add}]
  $$
 Proof Tree는 AST를 뒤집은 모양.
 If-then-else는 가질 수 있는데, If-then은 타입을 가질 수 없음.
 #### Type Environment
 어떻게 $x$가 variable이라고 할때 어떤 타입을 가지는지 알 수가 없음.
 Type Environment gives types for **free variables**.
 $$O \vdash e: T$$
 * $O$ is essentially **symbol table**.
 Complex Example of Declaration:
 ```c
 for (T1 i = 0;;) {
  exp
 }
 ```
 $$\frac{O[T1/i] \vdash \text{exp}: T2}{O\vdash \texttt{for}(i: T1) \set{\text{exp}: T2}}$$
 Complex Example of Class Attrs
 $$O_C(x) = T$$
 * forall attrs $x: T$ in class C
 $$O_C$$
 Complex Example of Class Methods
 ### Subtyping
--- a/notes/5.md
+++ b/notes/5.md
@@ -0,0 +1,92 @@
 # Semantic Analysis
 * after passing the lexical and syntax analysis, there are still errors. so correcting usage of variables, objects and function... are needed.
 **Semantic Analysis** ensures the program satisfies a set of rules regarding the usage of programming constructs:
 * identifiers declared before used
 * types
 * inheritance relationships
 * single definition
 There are two main categories of semantic analysis:
 * Scopes
 * Types
 ## Scope
 **Lexical Scope**: textual region in the program
 **Symbol Tables**
 Symantic checks refer to properties of identifier in the program; it need an environment to store identifier info: **symbol table**.
 | name | kind | type         |
 | ---- | ---- | ------------ |
 | foo  | func | `int -> int` |
 | m    | arg  | `int`        |
 | n    | arg  | `int`        |
 | tmp  | var  | char         |
 Each scope has symbol tables.
 And program has hierachy of symbol tables(scope).
 if the identifier is used traverse the hierachy of symbol tables upward until finding the identifier with the same name to determine the declaration from the current scope.
 ### Build a Symbol Table
 there are five operations:
 * insert scope
 * exit scope
 * find symbol(x)
 * add symbol(x)
 * check scope(x)
 ## Type
 * Type checking
 * Type inferencing
 Three Language Types:
 * Statically typed
 * Dynamically typed
 * Untyped(machine code)
 **Static Type Checking**
 Does not require additional type checking instructions at runtime.
 and guarantees that the executions are safe at compile time.
 modern languages require both static and dynamic type checking(union, void ptr)
 So what is types?
 A type indicates a description of a set of values and a set of allowed operations on those values.
 * Type Expressions: Describe the possible typse in the program, e.g., `int`, `char*`, `array[]`, `object`.
 * Type System: Defines types for language constructs (think about nodes in AST)
 ### Type Comparision Implementation
 1. Implement a method `Equals(T1, T2)`
   * must compare type trees of `T1` and `T2`
 2. Use unique objects for each distinct type
   * each type expression resolved to same type object everywhere
   * faster type comparision(use `==`)
   * object-oriendted: check subtyping of type objects
 for option 1
 ### Type Checking Methodology
 ### Inferecnce Rules
 ### Soundness
 $$\frac{i\text{ is an integer literal}}{\vdash i: \texttt{int}}[\texttt{int}]$$
 Some rules are sound but not necessary for a language: (not giving meanings)
 $$\frac{i\text{ is an integer literal}}{\vdash i \text{ is object} }$$
 $$\frac{e_1: \texttt{bool} \quad e_2: T}{\vdash \texttt{while} (e_1) \{ e_2 \} : \texttt{void}}[\texttt{while}]$$
--- a/notes/6.md
+++ b/notes/6.md
@@ -0,0 +1,68 @@
 # Code Generation 1
 ## Organization of Storage
 * Code Area
 * Static Area
 * Stack Area
 * Heap Area
 ### Stack Management using Register File
 * Stack pointer (SP): points to the top of the frame
 * Frame Pointer (FP, BP): points to the frame base
 because stack frame size is not always known at compile time.
 ### Saving Registers
 The callee may overwrite useful values in the registers.
 So caller's useful values should be stored in stack when function-call (`push`), and restored when callee return (`pop`). This role is done by both callee and caller (`caller-saved`, `callee-saved`).
 * Caller-saved registers
 used to hold **temporary quantities** that need not be preserved across calls.
 * Callee-saved registers
 used to hold **long-lived values** that should be preserved across calls.
 So Code before call:
 * push the params.
 * push caller-saved registers
 * push return address (curr `PC`) and jump to callee code
 Prologue of callee
 * push dynamic link (`FP`)
 * old stack pointer becomes new frame pointer
 * push callee-saved registers
 * push local var
 Epilogue
 * pop callee-saved registers
 * store return value at appropriate place
 * restore old stack pointer
 * pop old frame pointer
 * pop return addr and jump to that
 Code after call
 * pop caller-saved registers
 * use return value from appropriate place
 When accessing stack variable, use offsets from `FP`.
 ## Global Variables or Static Variables
 Global variables have same references for all scope. They are assigned a **fixed address once** (**statically allocated**).
 `Code > Static Data > Stack`
 ## Dynamic Allocation
 The dynamically allocated value outlives the procedure creating it (unless deleted).
 `Code > Static Data > Stack -> <- Heap`
--- a/notes/7.md
+++ b/notes/7.md
@@ -0,0 +1,96 @@
 # Code Generation 2
 ## Stack Machine
 Consider two instructions
 * `push i`
 * `add i`
 It is not efficient because all stack is considered as memory (which is slower than register).
 ### Utilizing Register Files
 Keep the top of the stack in a register, so `add` requires only a single memory access.
 * `acc <- i`
 * `push acc`
 * `pop`
 * `add`
 ### Code Generation From Stack Machine
 Assume that stack grows towards lower addresses.
 ## MIPS
 32 regs
 `$sp`, `$a0`, `$t1`
 * `lw`
 * `add`
 * `sw`
 * `addi`
 * `li`
 * `mv`
 Converting Stack to MIPS ISA
 * `acc <- i`
  * `li $a0 i`
 ### Optimizing
 no
 ## Branch
 `beq $1 $2 lbl`
 `b lbl`
 ## Function
 At Caller Side:
 1. saves the `$fp` to the stack
 2. saves the actual params in reverse order
 3. saves the return address to `$ra`
 At Callee Side:
 1. set `$fp` to `$sp`
 2. the callee saves the return address
 3. ...
 ## Temp Var
 Many various intermediate vars should be stored in the AR. But compiler can statically know how many temporary variables there are.
 Let $NT(e)$ is defined recursively by:
 $$NT(e1 + e2) = \max (NT(e1), NT(e2) + 1)$$
 for example:
 ### CG using NT
 add new args to the `cgen(e, nt)`
 reduce number of decrease `$sp` (`addi $sp $sp -4`)
 ## Intermediate Representation (IR)
 Before:
 Each Languages need respective, different Optimizer.
 Now:
 Common IR optimizer.
 IR is language-independent and machine-independent optimization.
 ### High-Level Assembly
 It uses unlimited number of registers.
 It uses assembly-like control structures (jmp and lbl).
 opcodes but some are higher level
 igen(e, t)
--- a/notes/8.md
+++ b/notes/8.md
@@ -0,0 +1,99 @@
 # Dataflow Analysis
 Optimization means improving resource utilization not changing what the program computes.
 Resource utilization means many things:
 * **Execution time**
 * Code size
 * Network messages sent.
 ## Basic Block (BB)
 A BB is a maximum sequence of instructions with **no labels**, **no jumps**
 All instructions in a BB has fixed control flow.
 ## Control Flow Graph
 ```mermaid
 flowchart TD
    Entry --> A
    A[BB1] --> B[BB2]
    A --> C[BB3]
    B --> D[BB4]
    C --> D
    D --> E[BB5]
    E --> G[BB7]
    E --> F[BB6]
    G --> Exit
    F --> Exit
 ```
 ## Local Optimization
 ### Algebraic Simplification
 x := x + 0 -> x := 0
 y := y ** 2 -> y := y * y
 x := x * 8 -> x := x << 3
 x := x * 15 -> t := x << 4; x := t - x
 ### Constant Folding
 x := 2 + 2 -> x := 4
 if 2 < 0 jump L -> nop
 if 2 > 0 jump L -> jump L
 But Constant folding can be dangerous on cross-compilation (in precision).
 ### Unreachable Code
 ### Dead Code Elimination
 ## Global Optimization
 It is not actually global but in control graph.
 In Basic Block, there are a few instructions (4-8). So only local optimization, it is not quite optimizable. There are many cases where the optimization can be performed through the entire CFG.
 ## Dataflow Analysis
 * Local Dataflow Analysis
 * Global Dataflow Analysis
 Analysis of Reaching Definition
 Effect of an Instruction
 `IN[b]` and `OUT[b]`
 Meet Operator 
 `IN[b] = union(OUT[p1]...OUT[pn])`
 ```c
 // init
 OUT[entry] = {}
 ```
 ## Liveness Analysis
 Liveness is the concept the variable is used in the future. It helps **eliminating dead code**.
 Transfer function
 * `USE[b]` set of variables used in `b`
 * `DEF[b]` set of variables defined in `b`
 so transfer function `f_b` for a basic block b:
 ```IN[b] = USE[b] + (OUT[b] - DEF[b])```
 for reaching defintion
 ```OUT[b] = union(INs)```
 For supporting cyclic graphs, repeated computation is needed.
--- a/notes/9.md
+++ b/notes/9.md
@@ -0,0 +1,28 @@
 # Control Flow Analysis
 Dominator
 for a given CFG **a node `x` dominates a node `y`** if every path from the Entry block to `y` contains `x`.
 * Each BB dominates itself
 * If `x dom y` and `y dom z` then `x dom z`
 * If `x dom z` and `y dom z` then either `x dom y` or `y dom x`
 Dominator Tree
 * initial node is a root
 * `x dom y` means that "`y` is a child of `x`"
 Natural Loops
 How to Find Natural Loop?: Introduction Backedge
 Important concepts in a loop
 * Header and Loop BB
 * Back Edges
 * Exit Edges
 * Preheader (Preloop)
 Loop-Invariant Computation
--- a/out/lex.md
+++ b/out/lex.md
@@ -0,0 +1,379 @@
 # Lexical Analysis(Scanner) Report
 * 주하진, 2024062806
 ## Compilation Environment and Method
 주어진 `Makefile`을 이용하여 C파일을 컴파일함.
 C파일은 `gcc`를 이용해서 컴파일한다.
 `Makefile`에서 산출되는 실행파일은 `cminus_cimpl`과 `cminus_lex`가 있으며 각각 `main.c util.c scan.c`, `main.c util.c lex.yy.c`를 컴파일한 오브젝트 파일을 필요로 한다.
 `lex.yy.c`는 `flex -o lex.yy.c cminus.l`을 통해 생성된다.
 ## C-Minus Language
 C-Minus에서 필요한 토큰타입변수와 그에 대한 설명은 다음과 같다.
 **특수 토큰**
 * `ENDFILE`: 파일끝
 * `ERROR`: 에러
 **키워드 토큰**
 * `IF`: `if`
 * `THEN`: `then`
 * `ELSE`: `else`
 * `WHILE`: `while`
 * `RETURN`: `return`
 * `INT`: `int`
 * `VOID`: `void`
 **가변길이 토큰**
 * `ID`: 식별자
 * `NUM`: 숫자
 **기호 토큰**
 * `ASSIGN`: `=`
 * `EQ`: `==`
 * `NE`: `!=`
 * `LT`: `<`
 * `LE`: `<=`
 * `GT`: `>`
 * `GE`: `>=`
 * `PLUS`: `+`
 * `MINUS`: `-`
 * `TIMES`: `*`
 * `OVER`: `/`
 * `LPAREN`: `(`
 * `RPAREN`: `)`
 * `LBRACE`: `[`
 * `RBRACE`: `]`
 * `LCURLY`: `{`
 * `RCURLY`: `}`
 * `SEMI`: `;`
 * `COMMA`: `,`
 **토큰에 포함되지 않는 스펙**
 * `/*` - `*/`: 주석 (토큰에 포함하지 않음)
 위와 같은 토큰 타입을 기반으로 토크나이징하는 것이 목적이다.
 ### Using `scan.c`
 `scan.c`에서는 올바른 `getToken`을 작성해야 한다.
 `getToken`을 작성하기에 앞서 전이가능한 `STATE`를 작성한다. 특히 `<`, `>`, `!`, `=`, `/`의 경우에는 단 한 글자만 받는게 아니라 그 다음 문자에 따라 산출할 토큰이 달라질 수 있으므로 그에 따른 `STATE`를 만든다.
 결과적으로 필요한 STATE는 다음과 같다.
 ```
 START, INOVER, INCOMMENT, ASTERCOMMENT, INASSIGN, INLT, INGT, INNE, INNUM, INID, DONE
 ```
 이를 이용해 `getToken`의 DFA를 작성할 수 있다.
 ```mermaid
 stateDiagram-v2
    START
    state comment {
        INOVER
        INCOMMENT
        ASTERCOMMENT
    }
    INASSIGN
    INLT
    INGT
    INNE
    state multichar {
    INNUM
    INID
    }
    state done {
        DONE
    }
    START --> INNUM: isdigit
    INNUM --> INNUM: isdigit
    INNUM --> DONE: else with unget
    START --> INID: isalpha
    INID --> INID: isalnum
    INID --> DONE: else with unget
    START --> INASSIGN: =
    INASSIGN --> DONE: =
    INASSIGN --> DONE: else with unget
    START --> INLT: \<
    INLT --> DONE: =
    INLT --> DONE: else with unget
    START --> INGT: \>
    INGT --> DONE: =
    INGT --> DONE: else with unget
    START --> INNE: !
    INNE --> DONE: =
    INNE --> DONE: else with unget and</br> return ERROR
    START --> INOVER: /
    INOVER --> INCOMMENT: \*
    INCOMMENT --> ASTERCOMMENT: \*
    ASTERCOMMENT --> INCOMMENT: else
    ASTERCOMMENT --> START: /
 ```
 이를 통해 `scan.c`를 작성하면 된다.
 이때 `tokenString`은 항상 넣되 (하지만 NUM, ID 토큰에서만 필요함) comment때만 안 넣으면 된다. `unget`할때도 안넣어야 한다.
 ### Using Lex (cminus.l)
 tiny의 lex파일처럼 간단하게 넣고 컴파일하면 된다.
 하나 중요한 점은 comment를 구현할 때, `prev`와 `now`를 각 과정에서 계속 업데이트 해가면서 `now == '/' && prev == '*'` 일때까지 계속 `input()`을 받아주면 된다.
 ## Examples & Result
 <table>
 <tr>
 <th>cminus file</th>
 <th>result text file</th>
 </tr>
 <tr>
 <td>
 ```c { .line-numbers }
 /* A program to perform Euclid's
   Algorithm to computer gcd */
 int gcd (int u, int v)
 {
 	if (v == 0) return u;
 	else return gcd(v,u-u/v*v);
 	/* u-u/v*v == u mod v */
 }
 void main(void)
 {
 	int x; int y;
 	x = input(); y = input();
 	output(gcd(x,y));
 }
 ```
 </td>
 <td>
 ```scanres
 C-MINUS COMPILATION: ./test1.cm
 	4: reserved word: int
 	4: ID, name= gcd
 	4: (
 	4: reserved word: int
 	4: ID, name= u
 	4: ,
 	4: reserved word: int
 	4: ID, name= v
 	4: )
 	5: {
 	6: reserved word: if
 	6: (
 	6: ID, name= v
 	6: ==
 	6: NUM, val= 0
 	6: )
 	6: reserved word: return
 	6: ID, name= u
 	6: ;
 	7: reserved word: else
 	7: reserved word: return
 	7: ID, name= gcd
 	7: (
 	7: ID, name= v
 	7: ,
 	7: ID, name= u
 	7: -
 	7: ID, name= u
 	7: /
 	7: ID, name= v
 	7: *
 	7: ID, name= v
 	7: )
 	7: ;
 	9: }
 	11: reserved word: void
 	11: ID, name= main
 	11: (
 	11: reserved word: void
 	11: )
 	12: {
 	13: reserved word: int
 	13: ID, name= x
 	13: ;
 	13: reserved word: int
 	13: ID, name= y
 	13: ;
 	14: ID, name= x
 	14: =
 	14: ID, name= input
 	14: (
 	14: )
 	14: ;
 	14: ID, name= y
 	14: =
 	14: ID, name= input
 	14: (
 	14: )
 	14: ;
 	15: ID, name= output
 	15: (
 	15: ID, name= gcd
 	15: (
 	15: ID, name= x
 	15: ,
 	15: ID, name= y
 	15: )
 	15: )
 	15: ;
 	16: }
 	17: EOF
 ```
 </td>
 </tr>
 <tr>
 <td>
 ```c {.line-numbers}
 void main(void)
 {
 	int i; int x[5];
 	i = 0;
 	while( i < 5 )
 	{
 		x[i] = input();
 		i = i + 1;
 	}
 	i = 0;
 	while( i <= 4 )
 	{
 		if( x[i] != 0 )
 		{
 			output(x[i]);
 		}
 	}
 }
 ```
 </td>
 <td>
 ```scanres
 C-MINUS COMPILATION: ./test2.cm
 	1: reserved word: void
 	1: ID, name= main
 	1: (
 	1: reserved word: void
 	1: )
 	2: {
 	3: reserved word: int
 	3: ID, name= i
 	3: ;
 	3: reserved word: int
 	3: ID, name= x
 	3: [
 	3: NUM, val= 5
 	3: ]
 	3: ;
 	5: ID, name= i
 	5: =
 	5: NUM, val= 0
 	5: ;
 	6: reserved word: while
 	6: (
 	6: ID, name= i
 	6: <
 	6: NUM, val= 5
 	6: )
 	7: {
 	8: ID, name= x
 	8: [
 	8: ID, name= i
 	8: ]
 	8: =
 	8: ID, name= input
 	8: (
 	8: )
 	8: ;
 	10: ID, name= i
 	10: =
 	10: ID, name= i
 	10: +
 	10: NUM, val= 1
 	10: ;
 	11: }
 	13: ID, name= i
 	13: =
 	13: NUM, val= 0
 	13: ;
 	14: reserved word: while
 	14: (
 	14: ID, name= i
 	14: <=
 	14: NUM, val= 4
 	14: )
 	15: {
 	16: reserved word: if
 	16: (
 	16: ID, name= x
 	16: [
 	16: ID, name= i
 	16: ]
 	16: !=
 	16: NUM, val= 0
 	16: )
 	17: {
 	18: ID, name= output
 	18: (
 	18: ID, name= x
 	18: [
 	18: ID, name= i
 	18: ]
 	18: )
 	18: ;
 	19: }
 	20: }
 	21: }
 	22: EOF
 ```
 </td>
 </tr>
 </table>
--- a/out/lex.pdf
+++ b/out/lex.pdf
--- a/out/parse.md
+++ b/out/parse.md
@@ -0,0 +1,267 @@
 # Syntax Analysis (Parser) Report
 * 주하진, 2024062806
 ## Compilation Environment and Method
 주어진 `Makefile`을 이용해 C파일과 `cminus.l`, `cminus.y`를 변환함.
 C파일은 `gcc`를 이용하고 `*.l`은 `flex`, `*.y`는 `yacc`을 이용함.
 `Makefile`의 빌드 결과물 `cminus_parser`를 만들기 위해서 `main.c`, `util.c`, `lex.yy.o`, `y.tab.o`를 필요로 한다.
 ## C-Minus Parser Implementation
 C-Minus Parser 구현을 위해 다음 세 파일의 큰 수정이 필요했다.
 * `globals.h`
 * `util.c`, `util.h`
 * `cminus.y` (Important)
 ### `globals.h`
 여러개의 Kind Enum을 추가하였다.
 * NodeKind(큰 분류)
 * StmtKind(Statement의 종류)
 * ExpKind(Expression의 종류)
 * DeclKind(Declaration의 종류)
 * TypeKind(Declaration에서 Type을 구분하기 위해 사용, 실제로 파스트리에 들어가진 않음, var_declaration에서 참조하기 위한 목적.)
 **StmtKind**
 * IfK: if문
 * IterK: while문
 * ReturnK: return문
 * CompK: 여러개 있는 중괄호(복합) 문
 **ExpKind**
 * AssignK: 할당문
 * OpK: 연산자가 포함된 표현식
 * ConstK: 상수
 * IdK: 식별자
 * ArrIdK: 배열 식별자
 * CallK: 함수 호출
 **DeclKind**
 * FuncK: 함수 선언
 * VarK: 변수 선언
 * ArrVarK: 배열 변수 선언
 * ArrParamK: 배열 매개변수
 * NonArrParamK: 매개변수
 **TypeKind**
 * TypeNameK: 선언의 타입
 -----
 `TreeNode`를 추가하였다.
 ```c
 typedef struct treeNode {
    struct treeNode *child[MAXCHILDREN];
    struct treeNode *sibling;
    int lineno;
    NodeKind nodekind;
    union {
        StmtKind stmt;
        ExpKind exp;
        DeclKind decl;
        TypeKind type;
    } kind;
    union {
        TokenType op;
        int val;
        char *name;
    } attr;
    ExpType type; /* for type checking of exps */
 } TreeNode;
 ```
 TreeNode 타입은 ParseTree의 노드를 나타내며, 자식 노드와 형제 노드를 가리키는 포인터 그리고 노드의 kind와 attr, type을 가진다.
 ### `util.c`, `util.h`
 `newStmtNode`, `newExpNode`, `newDeclNode`, `newTypeNode` 함수를 추가 및 수정했다. 각각 Statement, Expression, Declaration, Type 노드를 생성하는 함수이다.
 Type을 출력하기 위해 `printType` 함수를 추가하였다.
 printTree는 TreeNode를 출력하는 함수이다. nodeKind에 따라 구분하여 출력한다. 이때 type이 필요한 node이면 type도 같이 출력한다.
 ### `cminus.y`(Important)
 cminus.y에서 토큰의 선언은 다음과 같이 했다.
 ```yacc
 %token IF ELSE WHILE RETURN INT VOID
 %token EQ NE LT LE GT GE LPAREN RPAREN LBRACE LCURLY RBRACE RCURLY SEMI 
 %token ID NUM
 %left PLUS MINUS
 %left TIMES OVER
 %right ASSIGN
 %nonassoc THEN
 %nonassoc ELSE
 %token ERROR
 ```
 나머지 부분은 제공된 grammar와 tiny.y의 많은 부분을 참고하여 작성했다.
 이때 중요한 부분은 **dangling-else** 부분이다.
 ```yacc
 selection_stmt : IF LPAREN expression RPAREN statement %prec THEN {
  ...
 } | IF LPAREN expression RPAREN statement ELSE statement {
  ...
 };
 ```
 `single-if`문의 우선순위를 `ELSE`보다 낮은 `THEN`으로 지정하여 Shift/Reduce Conflict를 해결했다.
 ## Results
 다음은 테스트 C-Minus 프로그램과 그에 대한 파스트리 출력 결과이다.
 <table>
 <tr>
 <th>C-Minus Test Program</th>
 <th>Parse Tree Output</th>
 </tr><tr>
 <td>
 ```c
 void main(void)
 {
 	int i; int x[5];
 	i = 0;
 	while( i < 5 )
 	{
 		x[i] = input();
 		i = i + 1;
 	}
 	i = 0;
 	while( i <= 4 )
 	{
 		if( x[i] != 0 )
 		{
 			output(x[i]);
 		}
 	}
 }
 ```
 </td><td>
 ```txt
 C-MINUS COMPILATION: test.2.txt
 Syntax tree:
  Function Declaration: name = main, return type = void
    Void Parameter
    Compound Statement:
      Variable Declaration: name = i, type = int
      Variable Declaration: name = x, type = int[]
        Const: 5
      Assign:
        Variable: name = i
        Const: 0
      While Statement:
        Op: <
          Variable: name = i
          Const: 5
        Compound Statement:
          Assign:
            Variable: name = x
              Variable: name = i
            Call: function name = input
          Assign:
            Variable: name = i
            Op: +
              Variable: name = i
              Const: 1
      Assign:
        Variable: name = i
        Const: 0
      While Statement:
        Op: <=
          Variable: name = i
          Const: 4
        Compound Statement:
          If Statement:
            Op: !=
              Variable: name = x
                Variable: name = i
              Const: 0
            Compound Statement:
              Call: function name = output
                Variable: name = x
                  Variable: name = i
 ```
 </td></tr>
 <td><tr>
 <td>
 ```c
 int main(void){
    int a;
    int b;
    a = (b = 4) + 3;
    if(a==b+(c*b+d))
        while(1)
            if(1)
                a=2;
            else a=3;
 }
 ```
 </td><td>
 ```txt
 C-MINUS COMPILATION: test.cm
 Syntax tree:
  Function Declaration: name = main, return type = int
    Void Parameter
    Compound Statement:
      Variable Declaration: name = a, type = int
      Variable Declaration: name = b, type = int
      Assign:
        Variable: name = a
        Op: +
          Assign:
            Variable: name = b
            Const: 4
          Const: 3
      If Statement:
        Op: ==
          Variable: name = a
          Op: +
            Variable: name = b
            Op: +
              Op: *
                Variable: name = c
                Variable: name = b
              Variable: name = d
        While Statement:
          Const: 1
          If-Else Statement:
            Const: 1
            Assign:
              Variable: name = a
              Const: 2
            Assign:
              Variable: name = a
              Const: 3
 ```
 </td>
 </tr>
 </table>
--- a/out/parse.pdf
+++ b/out/parse.pdf
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@@ -0,0 +1,5 @@
 {
  "dependencies": {
    "crossnote": "^0.9.15"
  }
 }
--- a/pdf/L10.pdf
+++ b/pdf/L10.pdf
--- a/pdf/L11.pdf
+++ b/pdf/L11.pdf
--- a/pdf/L12.pdf
+++ b/pdf/L12.pdf
--- a/pdf/L3.pdf
+++ b/pdf/L3.pdf
--- a/pdf/L4.pdf
+++ b/pdf/L4.pdf
--- a/pdf/L5.pdf
+++ b/pdf/L5.pdf
--- a/pdf/L6.pdf
+++ b/pdf/L6.pdf
--- a/pdf/L7.pdf
+++ b/pdf/L7.pdf
--- a/pdf/L8.pdf
+++ b/pdf/L8.pdf
--- a/pdf/L9.pdf
+++ b/pdf/L9.pdf
--- a/pdf/P1.pdf
+++ b/pdf/P1.pdf
--- a/pdf/P2.pdf
+++ b/pdf/P2.pdf
--- a/pdf/P3.pdf
+++ b/pdf/P3.pdf
--- a/pdf/P4.pdf
+++ b/pdf/P4.pdf
--- a/src/2024062806.docx
+++ b/src/2024062806.docx
--- a/src/2024062806.pdf
+++ b/src/2024062806.pdf
--- a/src/Makefile
+++ b/src/Makefile
@@ -0,0 +1,46 @@
 # Makefile for C-Minus
 #
 # ./lex/tiny.l        --> ./cminus.l (from Project 1)
 # ./yacc/tiny.y       --> ./cminus.y (from Project 2)
 # ./yacc/globals.h    --> ./globals.h (from Project 2)
 CC = gcc
 CFLAGS = -W -Wall -g
 OBJS = main.o util.o lex.yy.o y.tab.o symtab.o analyze.o
 .PHONY: all clean
 all: cminus_semantic
 clean:
 	rm -vf cminus_semantic *.o lex.yy.c y.tab.c y.tab.h y.output
 cminus_semantic: $(OBJS)
 	$(CC) $(CFLAGS) $(OBJS) -o $@ -lfl
 main.o: main.c globals.h util.h scan.h parse.h y.tab.h analyze.h
 	$(CC) $(CFLAGS) -c main.c
 util.o: util.c util.h globals.h y.tab.h
 	$(CC) $(CFLAGS) -c util.c
 lex.yy.o: lex.yy.c scan.h globals.h y.tab.h util.h
 	$(CC) $(CFLAGS) -c lex.yy.c
 lex.yy.c: cminus.l
 	flex cminus.l
 y.tab.h: y.tab.c
 y.tab.o: y.tab.c parse.h
 	$(CC) $(CFLAGS) -c y.tab.c
 y.tab.c: cminus.y
 	yacc -d -v cminus.y
 analyze.o: analyze.c analyze.h globals.h y.tab.h symtab.h util.h
 	$(CC) $(CFLAGS) -c analyze.c
 symtab.o: symtab.c symtab.h
 	$(CC) $(CFLAGS) -c symtab.c
--- a/src/analyze.c
+++ b/src/analyze.c
@@ -1,159 +1,416 @@
 /****************************************************/
 /* File: analyze.c                                  */
 /* Semantic analyzer implementation                 */
-/* for the TINY compiler                            */
+/* for the CMinus compiler                          */
-/* Compiler Construction: Principles and Practice   */
+/* Yenru0                                           */
 /* Kenneth C. Louden                                */
 /****************************************************/
 #include "analyze.h"
 #include "globals.h"
 #include "symtab.h"
 #include "analyze.h"
-/* counter for variable memory locations */
+
-static int location = 0;
+static BucketList func_entry = NULL;
 static Scope func_scope;
 static TreeNode *func_params[MAX_PARAM_COUNT];
 static int func_param_count = 0;
 void gen_random_hex_16(char *buffer) {
    char *hex_chars = "0123456789abcdef";
    for (int i = 0; i < 16; i++) {
        buffer[i] = hex_chars[rand() % 16];
    }
    buffer[16] = '\0';
 }
 /* Procedure traverse is a generic recursive 
 * syntax tree traversal routine:
 * it applies preProc in preorder and postProc 
 * in postorder to tree pointed to by t
 */
-static void traverse( TreeNode * t,
+static void traverse(TreeNode *t,
-               void (* preProc) (TreeNode *),
+                     void (*preProc)(TreeNode *),
-               void (* postProc) (TreeNode *) )
+                     void (*postProc)(TreeNode *)) {
-{ if (t != NULL)
+    if (t != NULL) {
-  { preProc(t);
+        preProc(t);
-    { int i;
+        {
-      for (i=0; i < MAXCHILDREN; i++)
+            int i;
-        traverse(t->child[i],preProc,postProc);
+            for (i = 0; i < MAXCHILDREN; i++)
                traverse(t->child[i], preProc, postProc);
        }
        postProc(t);
        traverse(t->sibling, preProc, postProc);
    }
    postProc(t);
    traverse(t->sibling,preProc,postProc);
  }
 }
 /* nullProc is a do-nothing procedure to 
 * generate preorder-only or postorder-only
 * traversals from traverse
 */
-static void nullProc(TreeNode * t)
+static void nullProc(TreeNode *t) {
-{ if (t==NULL) return;
+    if (t == NULL) return;
-  else return;
+    else
        return;
 }
 /* Procedure insertNode inserts 
 * identifiers stored in t into 
 * the symbol table 
 */
-static void insertNode( TreeNode * t)
+static void insertNode(TreeNode *t) {
-{ switch (t->nodekind)
+    switch (t->nodekind) {
-  { case StmtK:
+        case ExpK:
-      switch (t->kind.stmt)
+            switch (t->kind.exp) {
-      { case AssignK:
+                case IdK:
-        case ReadK:
+                case ArrIdK: {
-          if (st_lookup(t->attr.name) == -1)
+                    BucketList entry = st_lookup(t->attr.name);
-          /* not yet in table, so treat as new definition */
+                    if (entry == NULL) {
-            st_insert(t->attr.name,t->lineno,location++);
+                        fprintf(listing, "Error: undeclared variable \"%s\" is used at line %d\n", t->attr.name, t->lineno);
-          else
+                        Error = TRUE;
-          /* already in table, so ignore location, 
+
-             add line number of use only */ 
+                        entry = st_try_insert(t->attr.name, SymbolVar, Undetermined, t->lineno);
-            st_insert(t->attr.name,t->lineno,0);
+                    } else {
-          break;
+                        st_entry_insert_line(entry, t->lineno);
                    }
                    t->scope = curr_scope();
                } break;
                case CallK: {
                    BucketList entry = st_lookup(t->attr.name);
                    if (entry == NULL) {
                        fprintf(listing, "Error: undeclared function \"%s\" is called at line %d\n", t->attr.name, t->lineno);
                        Error = TRUE;
                        entry = st_try_insert(t->attr.name, SymbolFunc, Undetermined, t->lineno);
                        entry->param_count = -1;
                        entry->returnType = Undetermined;
                    } else {
                        st_entry_insert_line(entry, t->lineno);
                    }
                    t->scope = curr_scope();
                }
                default:
                    break;
            }
            break;
        case StmtK:
            switch (t->kind.stmt) {
                case CompK:
                    if (func_scope != NULL) {
                        push_scope(func_scope);
                        func_scope = NULL;
                        for (int i = 0; i < func_param_count; i++) {
                            TreeNode *param = func_params[i];
                            func_entry->param_types[func_entry->param_count] = param->type;
                            func_entry->param_names[func_entry->param_count] = param->attr.name;
                            func_entry->param_count++;
                            BucketList param_entry = st_lookup_current(param->attr.name);
                            if (param_entry != NULL) {
                                fprintf(listing, "Error: Symbol \"%s\" is redefined at line %d (already defined at line", func_entry->param_names[i], param->lineno);
                                LineList lines = param_entry->lines;
                                while (lines != NULL) {
                                    fprintf(listing, " ");
                                    fprintf(listing, "%d", lines->lineno);
                                    lines = lines->next;
                                }
                                fprintf(listing, ")\n");
                                Error = TRUE;
                                st_entry_insert_line(param_entry, param->lineno);
                            } else {
                                st_try_insert(param->attr.name, SymbolParam, param->type, param->lineno);
                            }
                        }
                        func_entry = NULL;
                        func_scope = NULL;
                        func_param_count = 0;
                    } else {
                        char *parent_scope_name = curr_scope()->name;
                        char *new_name = (char *) malloc(255);
                        snprintf(new_name, 255, "%s.%d", parent_scope_name, curr_scope()->child_count);
                        push_scope(scope_new(new_name));
                    }
                    break;
                default:
                    break;
            }
            break;
        case DeclK:
            switch (t->kind.decl) {
                case FuncK: {
                    BucketList entry = st_lookup(t->attr.name);
                    if (entry != NULL) {
                        fprintf(listing, "Error: Symbol \"%s\" is redefined at line %d (already defined at line", t->attr.name, t->lineno);
                        LineList lines = entry->lines;
                        while (lines != NULL) {
                            fprintf(listing, " ");
                            fprintf(listing, "%d", lines->lineno);
                            lines = lines->next;
                        }
                        st_entry_insert_line(entry, t->lineno);
                        fprintf(listing, ")\n");
                        Error = TRUE;
                        char* random_name = (char *) calloc(1, 20);
                        gen_random_hex_16(random_name);
                        func_entry = st_try_insert(random_name, SymbolFunc, t->type, t->lineno);
                        t->scope = curr_scope();
                        func_scope = scope_new(random_name);
                    } else {
                        func_entry = st_try_insert(t->attr.name, SymbolFunc, t->type, t->lineno);
                        t->scope = curr_scope();
                        func_scope = scope_new(t->attr.name);
                    }
                } break;
                case ArrParamK:
                case NonArrParamK: {
                    if (func_scope != NULL) {
                        if (t->type == Void) {
                            if (t->attr.name != NULL) {
                                fprintf(listing, "Error: The void-type variable is declared at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                                Error = TRUE;
                            } else {
                                goto insert_param_exit;
                            }
                        }
                        func_params[func_param_count++] = t;
                    }
                insert_param_exit:
                } break;
                case VarK:
                case ArrVarK: {
                    BucketList entry = st_lookup_current(t->attr.name);
                    if (entry != NULL) {// ignore
                        fprintf(listing, "Error: Symbol \"%s\" is redefined at line %d (already defined at line", t->attr.name, t->lineno);
                        LineList lines = entry->lines;
                        while (lines != NULL) {
                            fprintf(listing, " ");
                            fprintf(listing, "%d", lines->lineno);
                            lines = lines->next;
                        }
                        fprintf(listing, ")\n");
                        st_entry_insert_line(entry, t->lineno);
                        Error = TRUE;
                    } else {
                        if (t->type == Void) {
                            fprintf(listing, "Error: The void-type variable is declared at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                            Error = TRUE;
                        }
                        t->scope = curr_scope();
                        st_try_insert(t->attr.name, SymbolVar, t->type, t->lineno);
                    }
                } break;
                default:
                    break;
            }
            break;
        default:
-          break;
+            break;
-      }
+    }
-      break;
+}
-    case ExpK:
+
-      switch (t->kind.exp)
+static void afterNode(TreeNode *t) {
-      { case IdK:
+    if (t->nodekind == StmtK && t->kind.stmt == CompK) {
-          if (st_lookup(t->attr.name) == -1)
+        pop_scope();
-          /* not yet in table, so treat as new definition */
+    }
            st_insert(t->attr.name,t->lineno,location++);
          else
          /* already in table, so ignore location, 
             add line number of use only */ 
            st_insert(t->attr.name,t->lineno,0);
          break;
        default:
          break;
      }
      break;
    default:
      break;
  }
 }
 /* Function buildSymtab constructs the symbol 
 * table by preorder traversal of the syntax tree
 */
-void buildSymtab(TreeNode * syntaxTree)
+void buildSymtab(TreeNode *syntaxTree) {
-{ traverse(syntaxTree,insertNode,nullProc);
+    st_init();
-  if (TraceAnalyze)
+    BucketList entry;
-  { fprintf(listing,"\nSymbol table:\n\n");
+    entry = st_try_insert("input", SymbolFunc, Integer, 0);
-    printSymTab(listing);
+    entry->param_count = 0;
-  }
+    // entry->returnType = Integer; /* not know */
    entry = st_try_insert("output", SymbolFunc, Void, 0);
    entry->returnType = Void;
    entry->param_types[0] = Integer;
    entry->param_names[0] = "value";
    entry->param_count = 1;
    push_scope(scope_new("output"));
    st_try_insert("value", SymbolParam, Integer, 0);
    pop_scope();
    traverse(syntaxTree, insertNode, afterNode);
    if (TraceAnalyze) {
        printSymTab(listing);
    }
 }
-static void typeError(TreeNode * t, char * message)
+static void typeError(TreeNode *t, char *message) {
-{ fprintf(listing,"Type error at line %d: %s\n",t->lineno,message);
+    fprintf(listing, "Type error at line %d: %s\n", t->lineno, message);
-  Error = TRUE;
+    Error = TRUE;
 }
-/* Procedure checkNode performs
+static void beforeCheckNode(TreeNode *t) {
- * type checking at a single tree node
+    if (t->nodekind == DeclK && t->kind.decl == FuncK) {
- */
+        func_entry = st_lookup(t->attr.name);
-static void checkNode(TreeNode * t)
+    }
-{ switch (t->nodekind)
+}
-  { case ExpK:
+static void checkNode(TreeNode *t) {
-      switch (t->kind.exp)
+    switch (t->nodekind) {
-      { case OpK:
+        case ExpK:
-          if ((t->child[0]->type != Integer) ||
+            switch (t->kind.exp) {
-              (t->child[1]->type != Integer))
+                case OpK: {
-            typeError(t,"Op applied to non-integer");
+                    TreeNode *left = t->child[0];
-          if ((t->attr.op == EQ) || (t->attr.op == LT))
+                    TreeNode *right = t->child[1];
-            t->type = Boolean;
+                    if (left->type != Integer || right->type != Integer) {
-          else
+                        fprintf(listing, "Error: invalid operation at line %d\n", t->lineno);
-            t->type = Integer;
+                        Error = TRUE;
-          break;
+                        t->type = Undetermined;
-        case ConstK:
+                    } else {
-        case IdK:
+                        t->type = Integer;
-          t->type = Integer;
+                    }
-          break;
+                } break;
-        default:
+                case ConstK:
-          break;
+                    t->type = Integer;
-      }
+                    break;
-      break;
+                case IdK: {
-    case StmtK:
+                    BucketList entry = st_lookup_from(t->attr.name, t->scope);
-      switch (t->kind.stmt)
+                    t->type = entry->type;
-      { case IfK:
+                } break;
-          if (t->child[0]->type == Integer)
+                case ArrIdK: {
-            typeError(t->child[0],"if test is not Boolean");
+                    BucketList entry = st_lookup_from(t->attr.name, t->scope);
-          break;
+                    if (entry->type != IntegerArray) {
-        case AssignK:
+                        fprintf(listing, "Error: Invalid array indexing at line %d (name : \"%s\"). indexing can only be allowed for int[] variables\n", t->lineno, t->attr.name);
-          if (t->child[0]->type != Integer)
+                        Error = TRUE;
-            typeError(t->child[0],"assignment of non-integer value");
+                    }
-          break;
+                    if (t->child[0]->type != Integer) {
-        case WriteK:
+                        fprintf(listing, "Error: Invalid array indexing at line %d (name : \"%s\"). indicies should be integer\n", t->lineno, t->attr.name);
-          if (t->child[0]->type != Integer)
+                        Error = TRUE;
-            typeError(t->child[0],"write of non-integer value");
+                    }
-          break;
+                    t->type = Integer;
-        case RepeatK:
+                } break;
          if (t->child[1]->type == Integer)
            typeError(t->child[1],"repeat test is not Boolean");
          break;
        default:
          break;
      }
      break;
    default:
      break;
-  }
+                case AssignK: {
                    TreeNode *left = t->child[0];
                    TreeNode *right = t->child[1];
                    if (left->type == Integer && right->type == Integer) {
                    } else if (left->type == IntegerArray && right->type == IntegerArray) {
                    } else {
                        fprintf(listing, "Error: invalid assignment at line %d\n", t->lineno);
                        Error = TRUE;
                    }
                    t->type = right->type;
                } break;
                case CallK: {
                    BucketList entry = st_lookup_from(t->attr.name, t->scope);// not null
                    if (entry->symbolKind != SymbolFunc) {
                        fprintf(listing, "Error: Invalid function call at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                        Error = TRUE;
                        goto check_callk_after;
                    }
                    TreeNode *arg = t->child[0];
                    int i = 0;// 파라미터 인덱스
                    if (entry->param_count == -1) {
                        fprintf(listing, "Error: Invalid function call at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                        Error = TRUE;
                        goto check_callk_after;
                    }
                    while (arg != NULL && i < entry->param_count) {
                        if (arg->type != entry->param_types[i]) {
                            fprintf(listing, "Error: Invalid function call at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                            Error = TRUE;
                            goto check_callk_after;
                        }
                        arg = arg->sibling;
                        i++;
                    }
                    if (arg != NULL) {
                        fprintf(listing, "Error: Invalid function call at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                        Error = TRUE;
                    } else if (i < entry->param_count) {
                        fprintf(listing, "Error: Invalid function call at line %d (name : \"%s\")\n", t->lineno, t->attr.name);
                        Error = TRUE;
                    }
                check_callk_after:
                    t->type = entry->returnType;
                } break;
                default:
                    break;
            }
            break;
        case StmtK:
            switch (t->kind.stmt) {
                case ReturnK: {
                    if (func_entry == NULL) {
                        fprintf(listing, "Error: Invalid return at line %d\n", t->lineno);
                        Error = TRUE;
                    }
                    TreeNode *retval = t->child[0]; /* nullalbe */
                    if (func_entry->returnType == Void) {
                        if (retval != NULL) {
                            fprintf(listing, "Error: Invalid return at line %d\n", t->lineno);
                            Error = TRUE;
                        }
                    } else {
                        if (retval == NULL) {
                            fprintf(listing, "Error: Invalid return at line %d\n", t->lineno);
                            Error = TRUE;
                        } else if (retval->type != func_entry->returnType) {
                            fprintf(listing, "Error: Invalid return at line %d\n", t->lineno);
                            Error = TRUE;
                        }
                    }
                } break;
                case IterK: {
                    TreeNode *condition = t->child[0];
                    if (condition->type != Integer) {
                        fprintf(listing, "Error: invalid condition at line %d\n", t->child[0]->lineno);
                        Error = TRUE;
                    }
                } break;
                case IfK: {
                    TreeNode *condition = t->child[0];
                    if (condition->type != Integer) {
                        fprintf(listing, "Error: invalid condition at line %d\n", t->child[0]->lineno);
                        Error = TRUE;
                    }
                } break;
                default:
                    break;
            }
            break;
        case DeclK:
            switch (t->kind.decl) {
                case FuncK:
                    func_entry = NULL;
                    break;
                default:
                    break;
            }
        default:
            break;
    }
 }
 /* Procedure typeCheck performs type checking 
 * by a postorder syntax tree traversal
 */
-void typeCheck(TreeNode * syntaxTree)
+void typeCheck(TreeNode *syntaxTree) {
-{ traverse(syntaxTree,nullProc,checkNode);
+    traverse(syntaxTree, beforeCheckNode, checkNode);
 }
--- a/src/lex/cminus.l
+++ b/src/lex/cminus.l
@@ -16,40 +16,50 @@ char tokenString[MAXTOKENLEN+1];
 digit       [0-9]
 number      {digit}+
 letter      [a-zA-Z]
-identifier  {letter}+
+identifier  {letter}({letter}|{digit})*
 newline     \n
 whitespace  [ \t]+
 %%
 "if"            {return IF;}
 "then"          {return THEN;}
 "else"          {return ELSE;}
-"end"           {return END;}
+"while"         {return WHILE;}
-"repeat"        {return REPEAT;}
+"return"        {return RETURN;}
-"until"         {return UNTIL;}
+"int"           {return INT;}
-"read"          {return READ;}
+"void"          {return VOID;}
-"write"         {return WRITE;}
+
-":="            {return ASSIGN;}
+"="             {return ASSIGN;}
-"="             {return EQ;}
+"=="            {return EQ;}
 "!="            {return NE;}
 "<"             {return LT;}
 "<="            {return LE;}
 ">"             {return GT;}
 ">="            {return GE;}
 "+"             {return PLUS;}
 "-"             {return MINUS;}
 "*"             {return TIMES;}
 "/"             {return OVER;}
 "("             {return LPAREN;}
 ")"             {return RPAREN;}
 "["             {return LBRACE;}
 "]"             {return RBRACE;}
 "{"             {return LCURLY;}
 "}"             {return RCURLY;}
 ";"             {return SEMI;}
 ","             {return COMMA;}
 {number}        {return NUM;}
 {identifier}    {return ID;}
 {newline}       {lineno++;}
 {whitespace}    {/* skip whitespace */}
-"{"             { char c;
+"/*"             { char now, prev;
                  do
-                  { c = input();
+                  { now = input();
-                    if (c == EOF) break;
+                    if (now == 0) break;
-                    if (c == '\n') lineno++;
+                    else if (now == '\n') lineno++;
-                  } while (c != '}');
+                    else if (now == '/' && prev == '*') break;
                    prev = now;
                  } while (1);
                }
 .               {return ERROR;}
--- a/src/cminus.y
+++ b/src/cminus.y
@@ -0,0 +1,344 @@
 /****************************************************/
 /* File: tiny.y                                     */
 /* The TINY Yacc/Bison specification file           */
 /* Compiler Construction: Principles and Practice   */
 /* Kenneth C. Louden                                */
 /****************************************************/
 %{
 #define YYPARSER /* distinguishes Yacc output from other code files */
 #include "globals.h"
 #include "util.h"
 #include "scan.h"
 #include "parse.h"
 #define YYSTYPE TreeNode *
 static char * savedName; /* for use in assignments */
 static int savedNumber;
 static int savedLineNo;  /* ditto */
 static TreeNode * savedTree; /* stores syntax tree for later return */
 static int yylex(void); // added 11/2/11 to ensure no conflict with lex
 int yyerror(char * message);
 %}
 %token IF ELSE WHILE RETURN INT VOID
 %token EQ NE LT LE GT GE LPAREN RPAREN LBRACE LCURLY RBRACE RCURLY SEMI COMMA
 %token ID NUM
 %left PLUS MINUS
 %left TIMES OVER
 %right ASSIGN
 %nonassoc THEN
 %nonassoc ELSE
 %token ERROR
 %% /* Grammar for C-MINUS */
 program : declaration_list
            {savedTree = $1;};
 declaration_list : declaration_list declaration {
                      YYSTYPE t = $1;
                      if (t != NULL) {
                        while (t->sibling != NULL) {
                          t = t->sibling;
                        }
                        t->sibling = $2;
                        $$ = $1;
                      } else { $$ = $2; };
                    }
                    | declaration { $$ = $1; }
                    ;
 declaration : var_declaration {$$ = $1; } | func_declaration { $$ = $1; };
 name_specifier : ID {
  savedName = copyString(tokenString);
  savedLineNo = lineno;
 };
 number_specifier : NUM {
  savedNumber = atoi(tokenString);
  savedLineNo = lineno;
 };
 var_declaration : type_specifier name_specifier SEMI {
  $$ = newDeclNode(VarK);
  $$->lineno = savedLineNo;
  $$->attr.name = savedName;
  $$->type = $1->type;
  free($1);
 } | type_specifier name_specifier LBRACE number_specifier RBRACE SEMI {
  $$ = newDeclNode(ArrVarK);
  $$->lineno = savedLineNo;
  if ($1->type == Integer)
    $$->type = IntegerArray;
  else
    $$->type = Void;
  $$->attr.name = savedName;
  free($1);
  $$->child[0] = newExpNode(ConstK);
  $$->child[0]->type = Integer;
  $$->child[0]->attr.val = savedNumber;
 };
 type_specifier : INT {
  $$ = newTypeNode(TypeNameK);
  $$->type = Integer;
 }
 | VOID {
  $$ = newTypeNode(TypeNameK);
  $$->type = Void;
 };
 func_declaration : type_specifier name_specifier {
  $$ = newDeclNode(FuncK);
  $$->lineno = savedLineNo;
  $$->attr.name = savedName;
  $$->type = $1->type;  /* 타입 바로 복사 */
 } LPAREN params RPAREN compound_stmt {
  $$ = $3;
  $$->child[0] = $5;  /* params */
  $$->child[1] = $7;  /* compound_stmt */
 };
 params : param_list { $$ = $1; } | VOID {
  $$ = newDeclNode(NonArrParamK);
  $$->type = Void;
 };
 param_list : param_list COMMA param {
  YYSTYPE t = $1;
  if (t != NULL) {
    while (t->sibling != NULL) {
      t = t->sibling;
    }  
    t->sibling = $3;
    $$ = $1;
  } else {
    $$ = $3;
    };
 } | param {$$ = $1; };
 param : type_specifier name_specifier {
  $$ = newDeclNode(NonArrParamK);
  $$->attr.name = savedName;
  $$->type = $1->type;
 } | type_specifier name_specifier LBRACE RBRACE {
  $$ = newDeclNode(ArrParamK);
  $$->attr.name = savedName;
  if ($1->type == Integer)
    $$->type = IntegerArray;
  else
    $$->type = Void;
 };
 compound_stmt : LCURLY local_declarations statement_list RCURLY {
  $$ = newStmtNode(CompK);
  $$->lineno = lineno;
  $$->child[0] = $2;
  $$->child[1] = $3;
 };
 local_declarations : local_declarations var_declaration {
  YYSTYPE t = $1;
  if (t != NULL) {
    while (t->sibling != NULL)
      t = t->sibling;
    t->sibling = $2;
    $$ = $1;
  } else $$ = $2;
 } | { $$ = NULL; };
 statement_list : statement_list statement {
  YYSTYPE t = $1;
  if (t != NULL) {
    while (t->sibling != NULL)
      t = t->sibling;
    t->sibling = $2;
    $$ = $1;
  } else $$ = $2;
 } | { $$ = NULL; };
 statement : expression_stmt { $$ = $1; }
          | compound_stmt { $$ = $1; }
          | selection_stmt { $$ = $1; }
          | iteration_stmt { $$ = $1; }
          | return_stmt { $$ = $1; }
          ;
 expression_stmt : expression SEMI { $$ = $1; }
                  | SEMI { $$ = NULL; }
                  ;
 selection_stmt : IF LPAREN expression RPAREN statement %prec THEN {
  $$ = newStmtNode(IfK);
  $$->lineno = lineno;
  $$->child[0] = $3;
  $$->child[1] = $5;
 } | IF LPAREN expression RPAREN statement ELSE statement {
  $$ = newStmtNode(IfK);
  $$->lineno = lineno;
  $$->child[0] = $3;
  $$->child[1] = $5;
  $$->child[2] = $7;
 };
 iteration_stmt : WHILE LPAREN expression RPAREN statement {
  $$ = newStmtNode(IterK);
  $$->lineno = lineno;
  $$->child[0] = $3;
  $$->child[1] = $5;
 };
 return_stmt : RETURN SEMI {
  $$ = newStmtNode(ReturnK);
  $$->lineno = lineno;
 } | RETURN expression SEMI {
  $$ = newStmtNode(ReturnK);
  $$->lineno = lineno;
  $$->child[0] = $2;
 };
 expression : var ASSIGN expression {
  $$ = newExpNode(AssignK);
  $$->lineno = lineno;
  $$->type = $3->type;
  $$->child[0] = $1;
  $$->child[1] = $3;
 } | simple_expression { $$ = $1; };
 var : name_specifier {
  $$ = newExpNode(IdK);
  $$->attr.name = savedName;
 } | name_specifier {
  $$ = newExpNode(ArrIdK);
  $$->attr.name = savedName;
 } LBRACE expression RBRACE {
  $$ = $2;
  $$->child[0] = $4;
 };
 simple_expression : additive_expression relop additive_expression {
  $$ = $2;
  $$->lineno = $2->lineno;
  $$->child[0] = $1;
  $$->child[1] = $3;
  $$->type = Integer;
 } | additive_expression { $$ = $1; };
 relop : LE {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = LE;
 } | LT {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = LT;
 } | GT {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = GT;
 } | GE {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = GE;
 } | EQ {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = EQ;
 } | NE {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = NE;
 };
 additive_expression : additive_expression addop term {
  $$ = $2;
  $$->lineno = $2->lineno;
  $$->child[0] = $1;
  $$->child[1] = $3;
 } | term { $$ = $1; };
 addop : PLUS {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = PLUS;
 } | MINUS {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = MINUS;
 };
 term : term mulop factor {
  $$ = $2;
  $$->lineno = $2->lineno;
  $$->child[0] = $1;
  $$->child[1] = $3;
 } | factor { $$ = $1; };
 mulop : TIMES {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = TIMES;
 } | OVER {
  $$ = newExpNode(OpK);
  $$->lineno = lineno;
  $$->attr.op = OVER;
 };
 factor : LPAREN expression RPAREN { $$ = $2; }
  | var { $$ = $1; }
  | call { $$ = $1; }
  | NUM {
  $$ = newExpNode(ConstK);
  $$->lineno = lineno;
  $$->type =  Integer;
  $$->attr.val = atoi(tokenString);
  }
  ;
 call : name_specifier {
    $$ = newExpNode(CallK);
    $$->lineno = lineno;
    $$->attr.name = savedName;
  } LPAREN args RPAREN {
    $$ = $2;
    $$->child[0] = $4;
  };
 args : arg_list { $$ = $1; } | { $$ = NULL; } ;
 arg_list : arg_list COMMA expression {
  YYSTYPE t = $1;
  if (t != NULL) {
    while (t->sibling != NULL)
      t = t->sibling;
    t->sibling = $3;
    $$ = $1;
  } else $$ = $3;
 } | expression { $$ = $1; } ;
 %%
 int yyerror(char * message)
 { fprintf(listing,"Syntax error at line %d: %s\n",lineno,message);
  fprintf(listing,"Current token: ");
  printToken(yychar,tokenString);
  Error = TRUE;
  return 0;
 }
 /* yylex calls getToken to make Yacc/Bison output
 * compatible with ealier versions of the TINY scanner
 */
 static int yylex(void)
 { return getToken(); }
 TreeNode * parse(void)
 { yyparse();
  return savedTree;
 }
--- a/src/globals.h
+++ b/src/globals.h
@@ -9,11 +9,14 @@
 #ifndef _GLOBALS_H_
 #define _GLOBALS_H_
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
 struct Scope;
 typedef struct Scope *Scope;
 #ifndef FALSE
 #define FALSE 0
 #endif
@@ -22,23 +25,56 @@
 #define TRUE 1
 #endif
 #ifndef YYPARSER
 #include "y.tab.h"
 #define ENDFILE 0
 #endif
 /* MAXRESERVED = the number of reserved words */
-#define MAXRESERVED 8
+#define MAXRESERVED 6
-typedef enum 
+#if 0
-    /* book-keeping tokens */
+typedef enum
-   {ENDFILE,ERROR,
+/* book-keeping tokens */
-    /* reserved words */
+{ ENDFILE,
-    IF,THEN,ELSE,END,REPEAT,UNTIL,READ,WRITE,
+  ERROR,
-    /* multicharacter tokens */
+  /* reserved words */
-    ID,NUM,
+  IF,
-    /* special symbols */
+  ELSE,
-    ASSIGN,EQ,LT,PLUS,MINUS,TIMES,OVER,LPAREN,RPAREN,SEMI
+  WHILE,
-   } TokenType;
+  RETURN,
  INT,
  VOID,
  /* multicharacter tokens */
  ID,
  NUM,
  /* special symbols */
  ASSIGN,
  EQ,
  NE,
  LT,
  LE,
  GT,
  GE,
  PLUS,
  MINUS,
  TIMES,
  OVER,
  LPAREN,
  RPAREN,
  LBRACE,
  RBRACE,
  LCURLY,
  RCURLY,
  SEMI,
  COMMA
 } TokenType;
 #endif
-extern FILE* source; /* source code text file */
+typedef int TokenType;
-extern FILE* listing; /* listing output text file */
+
-extern FILE* code; /* code text file for TM simulator */
+extern FILE *source;  /* source code text file */
 extern FILE *listing; /* listing output text file */
 extern FILE *code;    /* code text file for TM simulator */
 extern int lineno; /* source line number for listing */
@@ -46,26 +82,61 @@ extern int lineno; /* source line number for listing */
 /***********   Syntax tree for parsing ************/
 /**************************************************/
-typedef enum {StmtK,ExpK} NodeKind;
+typedef enum { StmtK,
-typedef enum {IfK,RepeatK,AssignK,ReadK,WriteK} StmtKind;
+               ExpK,
-typedef enum {OpK,ConstK,IdK} ExpKind;
+               DeclK,
               TypeK } NodeKind;
 typedef enum { CompK,
               IfK,
               IterK, /* WhileK*/
               ReturnK } StmtKind;
 typedef enum { AssignK,
               OpK,
               ConstK,
               IdK,
               ArrIdK,
               CallK } ExpKind;
 typedef enum { FuncK,
               VarK,
               ArrVarK,
               ArrParamK,
               NonArrParamK } DeclKind;
 typedef enum { TypeNameK } TypeKind;
 /* ExpType is used for type checking */
-typedef enum {Void,Integer,Boolean} ExpType;
+typedef enum { Void,
               Integer,
               IntegerArray,
               Undetermined
 } ExpType;
 typedef enum {
    SymbolVar,
    SymbolFunc,
    SymbolParam
 } SymbolKind;
 #define MAXCHILDREN 3
-typedef struct treeNode
+typedef struct treeNode {
-   { struct treeNode * child[MAXCHILDREN];
+    struct treeNode *child[MAXCHILDREN];
-     struct treeNode * sibling;
+    struct treeNode *sibling;
-     int lineno;
+    int lineno;
-     NodeKind nodekind;
+    NodeKind nodekind;
-     union { StmtKind stmt; ExpKind exp;} kind;
+    union {
-     union { TokenType op;
+        StmtKind stmt;
-             int val;
+        ExpKind exp;
-             char * name; } attr;
+        DeclKind decl;
-     ExpType type; /* for type checking of exps */
+        TypeKind type;
-   } TreeNode;
+    } kind;
    union {
        TokenType op;
        int val;
        char *name;
    } attr;
    ExpType type; /* for type checking of exps */
    Scope scope;
 } TreeNode;
 /**************************************************/
 /***********   Flags for tracing       ************/
@@ -100,5 +171,5 @@ extern int TraceAnalyze;
 extern int TraceCode;
 /* Error = TRUE prevents further passes if an error occurs */
-extern int Error; 
+extern int Error;
 #endif
--- a/src/main.c
+++ b/src/main.c
@@ -15,7 +15,7 @@
 /* set NO_CODE to TRUE to get a compiler that does not
 * generate code
 */
-#define NO_CODE FALSE
+#define NO_CODE TRUE
 #include "util.h"
 #if NO_PARSE
@@ -32,9 +32,9 @@
 /* allocate global variables */
 int lineno = 0;
-FILE * source;
+FILE *source;
-FILE * listing;
+FILE *listing;
-FILE * code;
+FILE *code;
 /* allocate and set tracing flags */
 int EchoSource = FALSE;
@@ -45,58 +45,57 @@ int TraceCode = FALSE;
 int Error = FALSE;
-main( int argc, char * argv[] )
+int main(int argc, char *argv[]) {
-{ TreeNode * syntaxTree;
+    TreeNode *syntaxTree;
-  char pgm[120]; /* source code file name */
+    char pgm[120]; /* source code file name */
-  if (argc != 2)
+    if (argc != 2) {
-    { fprintf(stderr,"usage: %s <filename>\n",argv[0]);
+        fprintf(stderr, "usage: %s <filename>\n", argv[0]);
-      exit(1);
+        exit(1);
    }
-  strcpy(pgm,argv[1]) ;
+    strcpy(pgm, argv[1]);
-  if (strchr (pgm, '.') == NULL)
+    if (strchr(pgm, '.') == NULL)
-     strcat(pgm,".tny");
+        strcat(pgm, ".tny");
-  source = fopen(pgm,"r");
+    source = fopen(pgm, "r");
-  if (source==NULL)
+    if (source == NULL) {
-  { fprintf(stderr,"File %s not found\n",pgm);
+        fprintf(stderr, "File %s not found\n", pgm);
-    exit(1);
+        exit(1);
-  }
+    }
-  listing = stdout; /* send listing to screen */
+    listing = stdout; /* send listing to screen */
-  fprintf(listing,"\nTINY COMPILATION: %s\n",pgm);
+    fprintf(listing, "\nC-MINUS COMPILATION: %s\n", pgm);
 #if NO_PARSE
-  while (getToken()!=ENDFILE);
+    while (getToken() != ENDFILE);
 #else
-  syntaxTree = parse();
+    syntaxTree = parse();
-  if (TraceParse) {
+    if (TraceParse) {
-    fprintf(listing,"\nSyntax tree:\n");
+        fprintf(listing, "\nSyntax tree:\n");
-    printTree(syntaxTree);
+        printTree(syntaxTree);
-  }
+    }
-#if !NO_ANALYZE
+#if !NO_ANALYZE
-  if (! Error)
+    if (!Error) {                           
-  { if (TraceAnalyze) fprintf(listing,"\nBuilding Symbol Table...\n");
+        if (TraceAnalyze) fprintf(listing, "\nBuilding Symbol Table...\n");
-    buildSymtab(syntaxTree);
+        buildSymtab(syntaxTree);
-    if (TraceAnalyze) fprintf(listing,"\nChecking Types...\n");
+        if (TraceAnalyze) fprintf(listing, "\nChecking Types...\n");
-    typeCheck(syntaxTree);
+        typeCheck(syntaxTree);
-    if (TraceAnalyze) fprintf(listing,"\nType Checking Finished\n");
+        if (TraceAnalyze) fprintf(listing, "\nType Checking Finished\n");
-  }
+    }
-#if !NO_CODE
+#if !NO_CODE
-  if (! Error)
+    if (!Error) {
-  { char * codefile;
+        char *codefile;
-    int fnlen = strcspn(pgm,".");
+        int fnlen = strcspn(pgm, ".");
-    codefile = (char *) calloc(fnlen+4, sizeof(char));
+        codefile = (char *) calloc(fnlen + 4, sizeof(char));
-    strncpy(codefile,pgm,fnlen);
+        strncpy(codefile, pgm, fnlen);
-    strcat(codefile,".tm");
+        strcat(codefile, ".tm");
-    code = fopen(codefile,"w");
+        code = fopen(codefile, "w");
-    if (code == NULL)
+        if (code == NULL) {
-    { printf("Unable to open %s\n",codefile);
+            printf("Unable to open %s\n", codefile);
-      exit(1);
+            exit(1);
        }
        codeGen(syntaxTree, codefile);
        fclose(code);
    }
    codeGen(syntaxTree,codefile);
    fclose(code);
  }
 #endif
 #endif
 #endif
-  fclose(source);
+    fclose(source);
-  return 0;
+    return 0;
 }
--- a/src/res.txt
+++ b/src/res.txt
@@ -0,0 +1,47 @@
 C-MINUS COMPILATION: ./test.cm
 Building Symbol Table...
 Error: undeclared function "x" is called at line 3
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     int            global        2           1  
 input          Function     int            global        0           0  
 output         Function     void           global        1           0  
 value          Variable     int            output        0           0  
 x              Function     undetermined   main          0           3  
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           int                            void          
 input          int                            void          
 output         void           
 -              -              value           int           
 x              undetermined                   undetermined  
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     int          
 input          Function     int          
 output         Function     void         
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int        
 main          1             x              void       
 Checking Types...
 Error: Invalid function call at line 3 (name : "x")
 Type Checking Finished
--- a/src/result_1.txt
+++ b/src/result_1.txt
@@ -0,0 +1,56 @@
 C-MINUS COMPILATION: test.1.txt
 Building Symbol Table...
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     void           global        3          11 
 input          Function     int            global        0           0   14   14 
 output         Function     void           global        1           0   15 
 gcd            Function     int            global        2           4    7   15 
 value          Variable     int            output        0           0 
 u              Variable     int            gcd           0           4    6    7    7 
 v              Variable     int            gcd           1           4    6    7    7    7 
 x              Variable     int            main          0          13   14   15 
 y              Variable     int            main          1          13   14   15 
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           void                           void        
 input          int                            void        
 output         void          
 -              -              value           int         
 gcd            int           
 -              -              u               int         
 -              -              v               int         
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     void         
 input          Function     int          
 output         Function     void         
 gcd            Function     int          
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int        
 gcd           1             u              int        
 gcd           1             v              int        
 main          1             x              int        
 main          1             y              int        
 Checking Types...
 Type Checking Finished
--- a/src/result_2.txt
+++ b/src/result_2.txt
@@ -0,0 +1,46 @@
 C-MINUS COMPILATION: test.2.txt
 Building Symbol Table...
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     void           global        2           1 
 input          Function     int            global        0           0    8 
 output         Function     void           global        1           0   18 
 value          Variable     int            output        0           0 
 i              Variable     int            main          0           3    5    6    8   10   10   13   14   16   18 
 x              Variable     int[]          main          1           3    8   16   18 
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           void                           void        
 input          int                            void        
 output         void          
 -              -              value           int         
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     void         
 input          Function     int          
 output         Function     void         
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int        
 main          1             i              int        
 main          1             x              int[]      
 Checking Types...
 Type Checking Finished
--- a/src/result_3.txt
+++ b/src/result_3.txt
@@ -0,0 +1,56 @@
 C-MINUS COMPILATION: test.3.txt
 Building Symbol Table...
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     int            global        3           6 
 input          Function     int            global        0           0 
 output         Function     void           global        1           0 
 x              Function     int            global        2           1   12 
 value          Variable     int            output        0           0 
 y              Variable     int            x             0           1    3 
 a              Variable     int            main          0           8   12 
 b              Variable     int            main          1           9   12 
 c              Variable     int            main          2          10   12 
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           int                            void        
 input          int                            void        
 output         void          
 -              -              value           int         
 x              int           
 -              -              y               int         
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     int          
 input          Function     int          
 output         Function     void         
 x              Function     int          
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int        
 x             1             y              int        
 main          1             a              int        
 main          1             b              int        
 main          1             c              int        
 Checking Types...
 Error: Invalid function call at line 12 (name : "x")
 Type Checking Finished
--- a/src/result_4.txt
+++ b/src/result_4.txt
@@ -0,0 +1,45 @@
 C-MINUS COMPILATION: test.4.txt
 Building Symbol Table...
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     int            global        2           1 
 input          Function     int            global        0           0 
 output         Function     void           global        1           0    4 
 value          Variable     int            output        0           0 
 x              Variable     int[]          main          0           3    4 
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           int                            void        
 input          int                            void        
 output         void          
 -              -              value           int         
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     int          
 input          Function     int          
 output         Function     void         
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int        
 main          1             x              int[]      
 Checking Types...
 Error: Invalid array indexing at line 4 (name : "x"). indices should be integer
 Type Checking Finished
--- a/src/sample.txt
+++ b/src/sample.txt
@@ -0,0 +1,44 @@
 C-MINUS COMPILATION: ./testcase/3_Semantic_Makefile_Testcase/mytest.8.txt
 Building Symbol Table...
 < Symbol Table >
 Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers
 -------------  -----------  -------------  ------------  --------  ------------
 main           Function     int            global        2           1
 input          Function     int            global        0           0
 output         Function     void           global        1           0
 value          Variable     int            output        0           0
 x              Variable     int            main          0           2    3
 < Functions >
 Function Name   Return Type   Parameter Name  Parameter Type
 -------------  -------------  --------------  --------------
 main           int                            void
 input          int                            void
 output         void
 -              -              value           int
 < Global Symbols >
 Symbol Name   Symbol Kind   Symbol Type
 -------------  -----------  -------------
 main           Function     int
 input          Function     int
 output         Function     void
 < Scopes >
 Scope Name   Nested Level   Symbol Name   Symbol Type
 ------------  ------------  -------------  -----------
 output        1             value          int
 main          1             x              int
 Checking Types...
 Error: Invalid function call at line 3 (name : "x")
 Type Checking Finished
--- a/src/scan.c
+++ b/src/scan.c
@@ -5,69 +5,81 @@
 /* Kenneth C. Louden                                */
 /****************************************************/
 #include "scan.h"
 #include "globals.h"
 #include "util.h"
 #include "scan.h"
 /* states in scanner DFA */
-typedef enum
+typedef enum { START,
-   { START,INASSIGN,INCOMMENT,INNUM,INID,DONE }
+               INOVER,
-   StateType;
+               INCOMMENT,
               ASTERCOMMENT,
               INASSIGN,
               INLT /* > */,
               INGT /* < */,
               INNE /* !*/,
               INNUM,
               INID,
               DONE } StateType;
 /* lexeme of identifier or reserved word */
-char tokenString[MAXTOKENLEN+1];
+char tokenString[MAXTOKENLEN + 1];
 /* BUFLEN = length of the input buffer for
   source code lines */
 #define BUFLEN 256
 static char lineBuf[BUFLEN]; /* holds the current line */
-static int linepos = 0; /* current position in LineBuf */
+static int linepos = 0;      /* current position in LineBuf */
-static int bufsize = 0; /* current size of buffer string */
+static int bufsize = 0;      /* current size of buffer string */
 static int EOF_flag = FALSE; /* corrects ungetNextChar behavior on EOF */
 /* getNextChar fetches the next non-blank character
   from lineBuf, reading in a new line if lineBuf is
   exhausted */
-static int getNextChar(void)
+static int getNextChar(void) {
-{ if (!(linepos < bufsize))
+    if (!(linepos < bufsize)) {
-  { lineno++;
+        lineno++;
-    if (fgets(lineBuf,BUFLEN-1,source))
+        if (fgets(lineBuf, BUFLEN - 1, source)) {
-    { if (EchoSource) fprintf(listing,"%4d: %s",lineno,lineBuf);
+            if (EchoSource) fprintf(listing, "%4d: %s", lineno, lineBuf);
-      bufsize = strlen(lineBuf);
+            bufsize = strlen(lineBuf);
-      linepos = 0;
+            linepos = 0;
-      return lineBuf[linepos++];
+            return lineBuf[linepos++];
-    }
+        } else {
-    else
+            EOF_flag = TRUE;
-    { EOF_flag = TRUE;
+            return EOF;
-      return EOF;
+        }
-    }
+    } else
-  }
+        return lineBuf[linepos++];
  else return lineBuf[linepos++];
 }
 /* ungetNextChar backtracks one character
   in lineBuf */
-static void ungetNextChar(void)
+static void ungetNextChar(void) {
-{ if (!EOF_flag) linepos-- ;}
+    if (!EOF_flag) linepos--;
 }
 /* lookup table of reserved words */
-static struct
+static struct {// keywords
-    { char* str;
+    char *str;
-      TokenType tok;
+    TokenType tok;
-    } reservedWords[MAXRESERVED]
+} reservedWords[MAXRESERVED] = {
-   = {{"if",IF},{"then",THEN},{"else",ELSE},{"end",END},
+        {"if", IF},
-      {"repeat",REPEAT},{"until",UNTIL},{"read",READ},
+        {"else", ELSE},
-      {"write",WRITE}};
+        {"while", WHILE},
        {"return", RETURN},
        {"int", INT},
        {"void", VOID},
 };
 /* lookup an identifier to see if it is a reserved word */
 /* uses linear search */
-static TokenType reservedLookup (char * s)
+static TokenType reservedLookup(char *s) {
-{ int i;
+    int i;
-  for (i=0;i<MAXRESERVED;i++)
+    for (i = 0; i < MAXRESERVED; i++)
-    if (!strcmp(s,reservedWords[i].str))
+        if (!strcmp(s, reservedWords[i].str))
-      return reservedWords[i].tok;
+            return reservedWords[i].tok;
-  return ID;
+    return ID;
 }
 /****************************************/
@@ -76,128 +88,191 @@ static TokenType reservedLookup (char * s)
 /* function getToken returns the 
 * next token in source file
 */
-TokenType getToken(void)
+TokenType getToken(void) { /* index for storing into tokenString */
-{  /* index for storing into tokenString */
+    int tokenStringIndex = 0;
-   int tokenStringIndex = 0;
+    /* holds current token to be returned */
-   /* holds current token to be returned */
+    TokenType currentToken;
-   TokenType currentToken;
+    /* current state - always begins at START */
-   /* current state - always begins at START */
+    StateType state = START;
-   StateType state = START;
+    /* flag to indicate save to tokenString */
-   /* flag to indicate save to tokenString */
+    int save;
-   int save;
+    while (state != DONE) {
-   while (state != DONE)
+        int c = getNextChar();
-   { int c = getNextChar();
+        save = TRUE;
-     save = TRUE;
+        /* main char process (state transition)*/
-     switch (state)
+        switch (state) {
-     { case START:
+            case START:
-         if (isdigit(c))
+                if (isdigit(c))
-           state = INNUM;
+                    state = INNUM;
-         else if (isalpha(c))
+                else if (isalpha(c))
-           state = INID;
+                    state = INID;
-         else if (c == ':')
+                else if ((c == ' ') || (c == '\t') || (c == '\n'))
-           state = INASSIGN;
+                    save = FALSE;
-         else if ((c == ' ') || (c == '\t') || (c == '\n'))
+                else if (c == '=')
-           save = FALSE;
+                    state = INASSIGN;
-         else if (c == '{')
+                else if (c == '!')
-         { save = FALSE;
+                    state = INNE;
-           state = INCOMMENT;
+                else if (c == '<') {
-         }
+                    state = INLT;
-         else
+                } else if (c == '>') {
-         { state = DONE;
+                    state = INGT;
-           switch (c)
+                } else if (c == '/') {// comment in or not
-           { case EOF:
+                    save = FALSE;
-               save = FALSE;
+                    state = INOVER;
-               currentToken = ENDFILE;
+                } else {
-               break;
+                    state = DONE;
-             case '=':
+                    switch (c) {
-               currentToken = EQ;
+                        case EOF:
-               break;
+                            save = FALSE;
-             case '<':
+                            currentToken = ENDFILE;
-               currentToken = LT;
+                            break;
-               break;
+                        case '+':
-             case '+':
+                            currentToken = PLUS;
-               currentToken = PLUS;
+                            break;
-               break;
+                        case '-':
-             case '-':
+                            currentToken = MINUS;
-               currentToken = MINUS;
+                            break;
-               break;
+                        case '*':
-             case '*':
+                            currentToken = TIMES;
-               currentToken = TIMES;
+                            break;
-               break;
+                        case '[':
-             case '/':
+                            currentToken = LBRACE;
-               currentToken = OVER;
+                            break;
-               break;
+                        case ']':
-             case '(':
+                            currentToken = RBRACE;
-               currentToken = LPAREN;
+                            break;
-               break;
+                        case '{':
-             case ')':
+                            currentToken = LCURLY;
-               currentToken = RPAREN;
+                            break;
-               break;
+                        case '}':
-             case ';':
+                            currentToken = RCURLY;
-               currentToken = SEMI;
+                            break;
-               break;
+                        case '(':
-             default:
+                            currentToken = LPAREN;
-               currentToken = ERROR;
+                            break;
-               break;
+                        case ')':
-           }
+                            currentToken = RPAREN;
-         }
+                            break;
-         break;
+                        case ';':
-       case INCOMMENT:
+                            currentToken = SEMI;
-         save = FALSE;
+                            break;
-         if (c == EOF)
+                        case ',':
-         { state = DONE;
+                            currentToken = COMMA;
-           currentToken = ENDFILE;
+                            break;
-         }
+                        default:
-         else if (c == '}') state = START;
+                            currentToken = ERROR;
-         break;
+                            break;
-       case INASSIGN:
+                    }
-         state = DONE;
+                }
-         if (c == '=')
+                break;
-           currentToken = ASSIGN;
+            /* begin comment process */
-         else
+            case INCOMMENT:
-         { /* backup in the input */
+                save = FALSE;
-           ungetNextChar();
+                if (c == EOF) {
-           save = FALSE;
+                    state = DONE;
-           currentToken = ERROR;
+                    currentToken = ENDFILE;
-         }
+                } else if (c == '*')// comment out
-         break;
+                    state = ASTERCOMMENT;
-       case INNUM:
+                break;
-         if (!isdigit(c))
+            case INOVER:
-         { /* backup in the input */
+                if (c == '*') {
-           ungetNextChar();
+                    save = FALSE;
-           save = FALSE;
+                    state = INCOMMENT;
-           state = DONE;
+                } else {
-           currentToken = NUM;
+                    state = DONE;
-         }
+                    ungetNextChar();
-         break;
+                    save = FALSE;
-       case INID:
+                    currentToken = OVER;
-         if (!isalpha(c))
+                }
-         { /* backup in the input */
+                break;
-           ungetNextChar();
+            case ASTERCOMMENT:
-           save = FALSE;
+                save = FALSE;
-           state = DONE;
+                if (c == EOF) {
-           currentToken = ID;
+                    state = DONE;
-         }
+                    currentToken = ENDFILE;
-         break;
+                } else if (c == '/') {
-       case DONE:
+                    state = START;
-       default: /* should never happen */
+                }
         fprintf(listing,"Scanner Bug: state= %d\n",state);
         state = DONE;
         currentToken = ERROR;
         break;
     }
     if ((save) && (tokenStringIndex <= MAXTOKENLEN))
       tokenString[tokenStringIndex++] = (char) c;
     if (state == DONE)
     { tokenString[tokenStringIndex] = '\0';
       if (currentToken == ID)
         currentToken = reservedLookup(tokenString);
     }
   }
   if (TraceScan) {
     fprintf(listing,"\t%d: ",lineno);
     printToken(currentToken,tokenString);
   }
   return currentToken;
 } /* end getToken */
                else {
                    state = INCOMMENT;
                }
                break;
            /* end comment process */
            case INASSIGN:
                state = DONE;
                if (c == '=')
                    currentToken = EQ;
                else { /* backup in the input */
                    ungetNextChar();
                    save = FALSE;
                    currentToken = ASSIGN;
                }
                break;
            case INNE:
                state = DONE;
                if (c == '=') {
                    currentToken = NE;
                } else {
                    ungetNextChar();
                    save = FALSE;
                    currentToken = ERROR;
                }
                break;
            case INLT:
                state = DONE;
                if (c == '=') {
                    currentToken = LE;
                } else {
                    ungetNextChar();
                    save = FALSE;
                    currentToken = LT;
                }
                break;
            case INGT:
                state = DONE;
                if (c == '=') {
                    currentToken = GE;
                } else {
                    ungetNextChar();
                    save = FALSE;
                    currentToken = GT;
                }
                break;
            case INNUM:
                if (!isdigit(c)) { /* backup in the input */
                    ungetNextChar();
                    save = FALSE;
                    state = DONE;
                    currentToken = NUM;
                }
                break;
            case INID:
                if (!isalnum(c)) { /* backup in the input */
                    ungetNextChar();
                    save = FALSE;
                    state = DONE;
                    currentToken = ID;
                }
                break;
            case DONE:
            default: /* should never happen */
                fprintf(listing, "Scanner Bug: state= %d\n", state);
                state = DONE;
                currentToken = ERROR;
                break;
        }
        if ((save) && (tokenStringIndex <= MAXTOKENLEN))
            tokenString[tokenStringIndex++] = (char) c;
        if (state == DONE) {
            tokenString[tokenStringIndex] = '\0';
            if (currentToken == ID)
                currentToken = reservedLookup(tokenString);
        }
    }
    if (TraceScan) {
        fprintf(listing, "\t%d: ", lineno);
        printToken(currentToken, tokenString);
    }
    return currentToken;
 } /* end getToken */
--- a/src/scan.h
+++ b/src/scan.h
@@ -7,6 +7,7 @@
 #ifndef _SCAN_H_
 #define _SCAN_H_
 #include "globals.h"
 /* MAXTOKENLEN is the maximum size of a token */
 #define MAXTOKENLEN 40
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -4,119 +4,506 @@
 /* (allows only one symbol table)                   */
 /* Symbol table is implemented as a chained         */
 /* hash table                                       */
 /* Compiler Construction: Principles and Practice   */
 /* Kenneth C. Louden                                */
 /****************************************************/
 #include "symtab.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "symtab.h"
-/* SIZE is the size of the hash table */
+Scope scope_stack[MAX_SCOPE_DEPTH];
-#define SIZE 211
+int scope_stack_top = -1;
 Scope scope_global;// no sibling no parent
 void st_init(void) {
    scope_global = scope_new("global");
    scope_global->depth = 0;
    scope_stack_top = 0;
    scope_stack[scope_stack_top] = scope_global;
 }
 /* SHIFT is the power of two used as multiplier
   in hash function  */
 #define SHIFT 4
 /* the hash function */
-static int hash ( char * key )
+static int hash(char *key) {
-{ int temp = 0;
+    int temp = 0;
-  int i = 0;
+    int i = 0;
-  while (key[i] != '\0')
+    while (key[i] != '\0') {
-  { temp = ((temp << SHIFT) + key[i]) % SIZE;
+        temp = ((temp << SHIFT) + key[i]) % SYMTAB_SIZE;
-    ++i;
+        ++i;
-  }
+    }
-  return temp;
+    return temp;
 }
-/* the list of line numbers of the source 
+Scope scope_new(char *scope_name) {// it
- * code in which a variable is referenced
+    Scope new_scope = (Scope) malloc(sizeof(struct Scope));
- */
+    new_scope->name = scope_name;
-typedef struct LineListRec
+    new_scope->depth = -1;
-   { int lineno;
+    new_scope->parent = NULL;
-     struct LineListRec * next;
+    new_scope->child = NULL;
-   } * LineList;
+    new_scope->child_last = NULL;
    new_scope->next_sibling = NULL;
    int i;
    for (i = 0; i < SYMTAB_SIZE; ++i) {
        new_scope->hashTable[i] = NULL;
    }
    new_scope->child_count = 0;
    new_scope->location = 0;
    return new_scope;
 }
-/* The record in the bucket lists for
+void pop_scope(void) {
- * each variable, including name, 
+    if (scope_stack_top == -1) {// empty
- * assigned memory location, and
+        return;
- * the list of line numbers in which
+    } else {
- * it appears in the source code
+        scope_stack[scope_stack_top] = NULL;
- */
+        scope_stack_top--;
-typedef struct BucketListRec
+    }
-   { char * name;
+}
     LineList lines;
     int memloc ; /* memory location for variable */
     struct BucketListRec * next;
   } * BucketList;
-/* the hash table */
+void push_scope(Scope scope) {
-static BucketList hashTable[SIZE];
+    if (scope_stack_top == MAX_SCOPE_DEPTH - 1) {// full
        return;
    } else {
        Scope before = curr_scope();
        if (before->child == NULL) {
            before->child = scope;
            before->child_last = scope;
        } else {
            before->child_last->next_sibling = scope;
            before->child_last = scope;
        }
        scope->parent = before;
        scope->depth = before->depth + 1;
        before->child_count++;
        scope_stack_top++;
        scope_stack[scope_stack_top] = scope;
    }
 }
-/* Procedure st_insert inserts line numbers and
+Scope curr_scope(void) {
- * memory locations into the symbol table
+    if (scope_stack_top == -1) {
- * loc = memory location is inserted only the
+        return NULL;
- * first time, otherwise ignored
+    } else {
- */
+        return scope_stack[scope_stack_top];
-void st_insert( char * name, int lineno, int loc )
+    }
-{ int h = hash(name);
+}
-  BucketList l =  hashTable[h];
+
-  while ((l != NULL) && (strcmp(name,l->name) != 0))
+BucketList st_try_insert(char *name, SymbolKind symbolkind, ExpType type, int lineno) {
-    l = l->next;
+    int h = hash(name);
-  if (l == NULL) /* variable not yet in table */
+    Scope scope = curr_scope();
-  { l = (BucketList) malloc(sizeof(struct BucketListRec));
+    BucketList *hashTable = scope->hashTable;
-    l->name = name;
+    BucketList l = hashTable[h];
-    l->lines = (LineList) malloc(sizeof(struct LineListRec));
+    while ((l != NULL) && (strcmp(name, l->name) != 0))
-    l->lines->lineno = lineno;
+        l = l->next;
-    l->memloc = loc;
+    if (l == NULL) { /* variable not yet in table */
-    l->lines->next = NULL;
+        l = (BucketList) malloc(sizeof(struct BucketListEntry));
-    l->next = hashTable[h];
+        l->name = name;
-    hashTable[h] = l; }
+        l->symbolKind = symbolkind;
-  else /* found in table, so just add line number */
+        l->lines = (LineList) malloc(sizeof(struct LineListEntry));
-  { LineList t = l->lines;
+        l->lines->lineno = lineno;
-    while (t->next != NULL) t = t->next;
+        l->symbolKind = symbolkind;
-    t->next = (LineList) malloc(sizeof(struct LineListRec));
+        if (symbolkind == SymbolFunc) {
            l->type = Void;
            l->returnType = type;
            l->param_count = 0;
        } else {
            l->type = type;
            l->returnType = type;
        }
        l->lines->next = NULL;
        l->memloc = scope->location;
        scope->location++;
        l->next = hashTable[h];
        hashTable[h] = l;
    } else { /* found in table, so just add line number */
        LineList t = l->lines;
        while (t->next != NULL)
            t = t->next;
        t->next = (LineList) malloc(sizeof(struct LineListEntry));
        t->next->lineno = lineno;
        t->next->next = NULL;
    }
    return l;
 }
 void st_entry_insert_line(BucketList entry, int lineno) {
    if (entry == NULL) return;
    LineList t = entry->lines;
    while (t->next != NULL)
        t = t->next;
    t->next = (LineList) malloc(sizeof(struct LineListEntry));
    t->next->lineno = lineno;
    t->next->next = NULL;
  }
 } /* st_insert */
 /* Function st_lookup returns the memory 
 * location of a variable or -1 if not found
 */
 int st_lookup ( char * name )
 { int h = hash(name);
  BucketList l =  hashTable[h];
  while ((l != NULL) && (strcmp(name,l->name) != 0))
    l = l->next;
  if (l == NULL) return -1;
  else return l->memloc;
 }
-/* Procedure printSymTab prints a formatted 
+BucketList st_lookup_current(char *name) {
- * listing of the symbol table contents 
+    int h = hash(name);
- * to the listing file
+    Scope scope = curr_scope();
- */
+    BucketList *hashTable = scope->hashTable;
-void printSymTab(FILE * listing)
+    BucketList l = hashTable[h];
-{ int i;
+    while ((l != NULL) && (strcmp(name, l->name) != 0))
  fprintf(listing,"Variable Name  Location   Line Numbers\n");
  fprintf(listing,"-------------  --------   ------------\n");
  for (i=0;i<SIZE;++i)
  { if (hashTable[i] != NULL)
    { BucketList l = hashTable[i];
      while (l != NULL)
      { LineList t = l->lines;
        fprintf(listing,"%-14s ",l->name);
        fprintf(listing,"%-8d  ",l->memloc);
        while (t != NULL)
        { fprintf(listing,"%4d ",t->lineno);
          t = t->next;
        }
        fprintf(listing,"\n");
        l = l->next;
-      }
+
    return l;
 }
 BucketList st_lookup(char *name) {
    int h = hash(name);
    Scope scope = curr_scope();
    while (scope != NULL) {
        BucketList *hashTable = scope->hashTable;
        BucketList l = hashTable[h];
        while ((l != NULL) && (strcmp(name, l->name) != 0))
            l = l->next;
        if (l != NULL) {
            return l;
        }
        scope = scope->parent;
    }
-  }
+    return NULL; /* not found */
-} /* printSymTab */
+}
 BucketList st_lookup_from(char *name, Scope scope) {
    int h = hash(name);
    while (scope != NULL) {
        BucketList *hashTable = scope->hashTable;
        BucketList l = hashTable[h];
        while ((l != NULL) && (strcmp(name, l->name) != 0))
            l = l->next;
        if (l != NULL) {
            return l;
        }
        scope = scope->parent;
    }
    return NULL; /* not found */
 }
 static void printEntry(FILE *listing, Scope scope, BucketList entry) {
    if (entry == NULL) return;
    fprintf(listing, "%-13s", entry->name);
    fprintf(listing, "  ");
    switch (entry->symbolKind) {
        case SymbolVar:
            fprintf(listing, "%-11s", "Variable");
            break;
        case SymbolFunc:
            fprintf(listing, "%-11s", "Function");
            break;
        case SymbolParam:
            fprintf(listing, "%-11s", "Variable");
            break;
    }
    fprintf(listing, "  ");
    ExpType type;
    if (entry->symbolKind == SymbolFunc) {
        type = entry->returnType;
    } else {
        type = entry->type;
    }
    switch (type) {
        case Void:
            fprintf(listing, "%-13s", "void");
            break;
        case Integer:
            fprintf(listing, "%-13s", "int");
            break;
        case IntegerArray:
            fprintf(listing, "%-13s", "int[]");
            break;
        case Undetermined:
            fprintf(listing, "%-13s", "undetermined");
    }
    //
    fprintf(listing, "  ");
    fprintf(listing, "%-12s", scope->name);
    //
    fprintf(listing, "  ");
    fprintf(listing, "%-8d", entry->memloc);
    fprintf(listing, "  ");
    LineList t = entry->lines;
    while (t != NULL) {
        fprintf(listing, "%3d", t->lineno);
        fprintf(listing, "  ");
        t = t->next;
    }
    fprintf(listing, "\n");
 }
 static void printScopeTable(FILE *listing, Scope scope) {
    if (scope == NULL) return;
    int count = 0;
    for (int i = 0; i < SYMTAB_SIZE; ++i) {
        BucketList l = scope->hashTable[i];
        while (l != NULL) {
            printEntry(listing, scope, l);
            count++;
            l = l->next;
        }
    }
    /*
    if (count > 0) {
        BucketList *entries = (BucketList *) malloc(sizeof(BucketList) * count);
        int idx = 0;
        for (int i = 0; i < SYMTAB_SIZE; ++i) {
            BucketList l = scope->hashTable[i];
            while (l != NULL) {
                entries[idx++] = l;
                l = l->next;
            }
        }
        for (int i = 1; i < count; ++i) {
            BucketList key = entries[i];
            int j = i - 1;
            while (j >= 0 && entries[j]->memloc > key->memloc) {
                entries[j + 1] = entries[j];
                --j;
            }
            entries[j + 1] = key;
        }
        for (int i = 0; i < count; ++i) {
            printEntry(listing, scope, entries[i]);
        }
        free(entries);
    }
        */
    //fprintf(listing, "\n");
 }
 static void printScope(FILE *listing, Scope scope) {
    if (scope == NULL) return;
    fprintf(listing, "Scope Name: %s, Depth: %d\n", scope->name, scope->depth);
    fprintf(listing, "-----------------------------------------\n");
    fprintf(listing, "Variable Name  Symbol Kind  Type       Location  Line Numbers\n");
    fprintf(listing, "------------------------------------------------------------\n");
    printScopeTable(listing, scope);
 }
 static void printScopeRecursive(FILE *listing, Scope scope) {
    if (scope == NULL) return;
    printScope(listing, scope);
    Scope child = scope->child;
    while (child != NULL) {
        printScopeRecursive(listing, child);
        child = child->next_sibling;
    }
 }
 static void printScopeTree(FILE *listing) {
    if (scope_global == NULL) return;
    Scope current_scope = scope_global;
    printScopeRecursive(listing, current_scope);
 }
 static void printScopeTableRecursive(FILE *listing, Scope scope) {
    if (scope == NULL) return;
    printScopeTable(listing, scope);
    Scope child = scope->child;
    while (child != NULL) {
        printScopeTableRecursive(listing, child);
        child = child->next_sibling;
    }
 }
 static void printFunctionTableRecursive(FILE *listing, Scope scope) {
    for (int i = 0; i < SYMTAB_SIZE; ++i) {
        BucketList entry = scope->hashTable[i];
        while (entry != NULL) {
            if (entry->symbolKind == SymbolFunc) {
                fprintf(listing, "%-13s", entry->name);
                fprintf(listing, "  ");
                switch (entry->returnType) {
                    case Void:
                        fprintf(listing, "%-13s", "void");
                        break;
                    case Integer:
                        fprintf(listing, "%-13s", "int");
                        break;
                    case IntegerArray:
                        fprintf(listing, "%-13s", "int[]");
                        break;
                    case Undetermined:
                        fprintf(listing, "%-13s", "undetermined");
                }
                if (entry->param_count == -1) {
                    fprintf(listing, "                  ");
                    fprintf(listing, "%-14s", "undetermined");
                    entry = entry->next;
                    fprintf(listing, "\n");
                    continue;
                } else if (entry->param_count == 0) {
                    fprintf(listing, "                  ");
                    fprintf(listing, "%-14s", "void");
                    entry = entry->next;
                    fprintf(listing, "\n");
                    continue;
                }
                fprintf(listing, "  \n");
                for (int j = 0; j < entry->param_count; j++) {
                    fprintf(listing, "-              -            ");
                    fprintf(listing, "  %-14s", entry->param_names[j]);
                    fprintf(listing, "  ");
                    switch (entry->param_types[j]) {
                        case Void:
                            fprintf(listing, "%-14s", "void");
                            break;
                        case Integer:
                            fprintf(listing, "%-14s", "int");
                            break;
                        case IntegerArray:
                            fprintf(listing, "%-14s", "int[]");
                            break;
                        case Undetermined:
                            fprintf(listing, "%-14s", "undetermined");
                    }
                    fprintf(listing, "\n");
                }
            }
            entry = entry->next;
        }
    }
    Scope child = scope->child;
    while (child != NULL) {
        printFunctionTableRecursive(listing, child);
        child = child->next_sibling;
    }
 }
 static void printFunctionTable(FILE *listing) {
    if (scope_global == NULL) return;
    printFunctionTableRecursive(listing, scope_global);
 }
 static void printGlobalSymbols(FILE *listing) {
    if (scope_global == NULL) return;
    for (int i = 0; i < SYMTAB_SIZE; ++i) {
        BucketList entry = scope_global->hashTable[i];
        while (entry != NULL) {
            fprintf(listing, "%-13s  ", entry->name);
            switch (entry->symbolKind) {
                case SymbolVar:
                    fprintf(listing, "%-11s  ", "Variable");
                    break;
                case SymbolFunc:
                    fprintf(listing, "%-11s  ", "Function");
                    break;
                case SymbolParam:
                    fprintf(listing, "%-11s  ", "Variable");
                    break;
            }
            ExpType type;
            if (entry->symbolKind == SymbolFunc) {
                type = entry->returnType;
            } else {
                type = entry->type;
            }
            switch (type) {
                case Void:
                    fprintf(listing, "%-13s", "void");
                    break;
                case Integer:
                    fprintf(listing, "%-13s", "int");
                    break;
                case IntegerArray:
                    fprintf(listing, "%-13s", "int[]");
                    break;
                case Undetermined:
                    fprintf(listing, "%-13s", "undetermined");
            }
            fprintf(listing, "\n");
            entry = entry->next;
        }
    }
 }
 static void printScopeTableAdvancedRecursive(FILE *listing, Scope scope) {
    if (scope == NULL) return;
    int no_sym = TRUE;
    for (int i = 0; i < SYMTAB_SIZE; ++i) {
        BucketList entry = scope->hashTable[i];
        while (entry != NULL) {
            no_sym = FALSE;
            fprintf(listing, "%-12s", scope->name);
            fprintf(listing, "  ");
            fprintf(listing, "%-12d", scope->depth);
            fprintf(listing, "  ");
            fprintf(listing, "%-13s", entry->name);
            fprintf(listing, "  ");
            switch (entry->type) {
                case Void:
                    fprintf(listing, "%-11s", "void");
                    break;
                case Integer:
                    fprintf(listing, "%-11s", "int");
                    break;
                case IntegerArray:
                    fprintf(listing, "%-11s", "int[]");
                    break;
                case Undetermined:
                    fprintf(listing, "%-11s", "undetermined");
            }
            fprintf(listing, "\n");
            entry = entry->next;
        }
    }
    if (!no_sym) fprintf(listing, "\n");
    Scope child = scope->child;
    while (child != NULL) {
        printScopeTableAdvancedRecursive(listing, child);
        child = child->next_sibling;
    }
 }
 static void printScopeTableAdvanced(FILE *listing) {
    if (scope_global == NULL) return;
    Scope current_scope;
    current_scope = scope_global->child;
    while (current_scope != NULL) {
        printScopeTableAdvancedRecursive(listing, current_scope);
        current_scope = current_scope->next_sibling;
    }
 }
 void printSymTab(FILE *listing) {
    Scope curr = scope_global;
    fprintf(listing, "\n\n< Symbol Table >\n");
    fprintf(listing, " Symbol Name   Symbol Kind   Symbol Type    Scope Name   Location  Line Numbers\n");
    fprintf(listing, "-------------  -----------  -------------  ------------  --------  ------------\n");
    printScopeTableRecursive(listing, curr);
    fprintf(listing, "\n\n< Functions >\n");
    fprintf(listing, "Function Name   Return Type   Parameter Name  Parameter Type\n");
    fprintf(listing, "-------------  -------------  --------------  --------------\n");
    printFunctionTable(listing);
    fprintf(listing, "\n\n< Global Symbols >\n");
    fprintf(listing, " Symbol Name   Symbol Kind   Symbol Type\n");
    fprintf(listing, "-------------  -----------  -------------\n");
    printGlobalSymbols(listing);
    fprintf(listing, "\n\n< Scopes >\n");
    fprintf(listing, " Scope Name   Nested Level   Symbol Name   Symbol Type\n");
    fprintf(listing, "------------  ------------  -------------  -----------\n");
    printScopeTableAdvanced(listing);
 }
--- a/src/symtab.h
+++ b/src/symtab.h
@@ -1,9 +1,7 @@
 /****************************************************/
 /* File: symtab.h                                   */
-/* Symbol table interface for the TINY compiler     */
+/* Symbol table interface for the CMINUS COMPILER   */
-/* (allows only one symbol table)                   */
+/* Modified by Yenru0                               */
 /* Compiler Construction: Principles and Practice   */
 /* Kenneth C. Louden                                */
 /****************************************************/
 #ifndef _SYMTAB_H_
@@ -11,22 +9,130 @@
 #include "globals.h"
-/* Procedure st_insert inserts line numbers and
+/**
- * memory locations into the symbol table
+ * it is the size of the hash table
- * loc = memory location is inserted only the
+*/
- * first time, otherwise ignored
+#define SYMTAB_SIZE 211
 */
 void st_insert( char * name, int lineno, int loc );
-/* Function st_lookup returns the memory 
+#define MAX_SCOPE_DEPTH 1557
 * location of a variable or -1 if not found
 */
 int st_lookup ( char * name );
-/* Procedure printSymTab prints a formatted 
+#define MAX_PARAM_COUNT 32
- * listing of the symbol table contents 
+
- * to the listing file
+/* the list of line numbers of the source 
 * code in which a variable is referenced
 */
-void printSymTab(FILE * listing);
+typedef struct LineListEntry {
    int lineno;
    struct LineListEntry *next;
 } * LineList;
 /* The record in the bucket lists for
 * each variable, including name, 
 * assigned memory location, and
 * the list of line numbers in which
 * it appears in the source code
 */
 typedef struct BucketListEntry {
    char *name;
    LineList lines;
    SymbolKind symbolKind;
    ExpType type;
    ExpType param_types[MAX_PARAM_COUNT];
    char* param_names[MAX_PARAM_COUNT];
    int param_count;
    ExpType returnType;
    int memloc; /* memory location for variable */
    struct BucketListEntry *next;
 } * BucketList;
 struct Scope {
    char *name;
    int depth;
    struct Scope *parent;
    struct Scope *child;
    struct Scope *child_last;
    struct Scope *next_sibling;
    int child_count;
    int location;
    BucketList hashTable[SYMTAB_SIZE];
 };
 extern Scope scope_global;// no sibling no parent
 extern Scope scope_stack[MAX_SCOPE_DEPTH];
 extern int scope_stack_top;
 /**
 * before using the symbol table, initialize the global scope
 */
 void st_init(void);
 /**
 * create a new scope with given name
 * @note it does not link parent or insert into stack/list
 * @param scope_name: name of the scope
 * @return the created scope
 */
 Scope scope_new(char *scope_name);
 /**
 * pop the current scope from the scope stack
 */
 void pop_scope(void);
 /**
 * push a scope into the scope stack
 * @note it does link the parent or siblings to construct tree
 * @param scope: the scope to be pushed
 */
 void push_scope(Scope scope);
 /**
 * get the top of the scope stack wit
 * @return the current scope or NULL if the stack is empty
 */
 Scope curr_scope(void);
 /**
 * insert a variable into the symbol table of the current scope
 * or add a line number if it already exists
 * @param name name of the variable
 * @param symbolkind kind of the symbol
 * @param type type of the variable
 * @param lineno line number of the variable
 * @return 0 if success, -1 if failure
 */
 BucketList st_try_insert(char *name, SymbolKind symbolkind, ExpType type, int lineno);
 /**
 * insert a line number into the variable's line list
 * @param entry the bucket list entry of the variable
 * @param lineno the line number to be inserted
 */
 void st_entry_insert_line(BucketList entry, int lineno);
 /**
 * lookup a variable in the current scope
 * @param name name of the variable to lookup
 * @return the bucket list entry of the variable or NULL if not found
 */
 BucketList st_lookup_current(char *name);
 /**
 * lookup a variable from the top scope to root
 * @param name name of the variable to lookup
 * @return the bucket list entry of the variable or NULL if not found
 */
 BucketList st_lookup(char *name);
 /**
 * lookup a variable from the given scope to root
 * @param name name of the variable to lookup
 * @param scope the scope to start lookup from
 * @return the bucket list entry of the variable or NULL if not found
 */
 BucketList st_lookup_from(char *name, Scope scope);
 void printSymTab(FILE *listing);
 #endif
--- a/src/test.cm
+++ b/src/test.cm
@@ -0,0 +1,42 @@
 int zero(void)
 {
  return 0;
 }
 int first(int data[])
 {
  return data[0];
 }
 void scopedemo(void)
 {
  int outer;
  outer = 1;
  {
    int outer;
    outer = outer + 2;
  }
 }
 void output(void)
 {
  return;
 }
 int input;
 void main(void)
 {
  int arr[2];
  arr[0] = 5;
  scopedemo();
  first(arr);
  zero();
  zero(1);
  {
    int blockOnly;
    blockOnly = arr[0];
  }
  blockOnly;
  return;
 }
--- a/src/test_1.cm
+++ b/src/test_1.cm
@@ -0,0 +1,13 @@
 int gcd (int u, int v)
 {
 	if (v == 0) return u;
 	else return gcd(v,u-u/v*v);
 	/* u-u/v*v == u mod v */
 }
 void main(void k)
 {
 	int x; int y;
 	x = input(); y = input();
 	output(gcd(x,y));
 }
--- a/src/test_2.cm
+++ b/src/test_2.cm
@@ -0,0 +1,21 @@
 void main(void)
 {
 	int i; int x[5];
 	i = 0;
 	while( i < 5 )
 	{
 		x[i] = input();
 		i = i + 1;
 	}
 	i = 0;
 	while( i <= 4 )
 	{
 		if( x[i] != 0 )
 		{
 			output(x[i]);
 		}
 	}
 }
--- a/src/test_3.cm
+++ b/src/test_3.cm
@@ -0,0 +1,13 @@
 int x(int y)
 {
    return y + 1;
 }
 int main(void)
 {
    int a;
    int b;
    int c;
    return x(a, b, c);
 }
--- a/src/test_4.cm
+++ b/src/test_4.cm
@@ -0,0 +1,7 @@
 int main(void)
 {
    int x[5];
    x[output(5)] = 3 + 5;
    return 0;
 }
--- a/src/util.c
+++ b/src/util.c
@@ -6,172 +6,309 @@
 /* Kenneth C. Louden                                */
 /****************************************************/
 #include "globals.h"
 #include "util.h"
 #include "globals.h"
 /* Procedure printToken prints a token 
 * and its lexeme to the listing file
 */
-void printToken( TokenType token, const char* tokenString )
+void printToken(TokenType token, const char *tokenString) {
-{ switch (token)
+    switch (token) {
-  { case IF:
+        case IF:
-    case THEN:
+        case ELSE:
-    case ELSE:
+        case WHILE:
-    case END:
+        case RETURN:
-    case REPEAT:
+        case INT:
-    case UNTIL:
+        case VOID:
-    case READ:
+            fprintf(listing,
-    case WRITE:
+                    "reserved word: %s\n", tokenString);
-      fprintf(listing,
+            break;
-         "reserved word: %s\n",tokenString);
+        case ASSIGN:
-      break;
+            fprintf(listing, "=\n");
-    case ASSIGN: fprintf(listing,":=\n"); break;
+            break;
-    case LT: fprintf(listing,"<\n"); break;
+        case EQ:
-    case EQ: fprintf(listing,"=\n"); break;
+            fprintf(listing, "==\n");
-    case LPAREN: fprintf(listing,"(\n"); break;
+            break;
-    case RPAREN: fprintf(listing,")\n"); break;
+        case NE:
-    case SEMI: fprintf(listing,";\n"); break;
+            fprintf(listing, "!=\n");
-    case PLUS: fprintf(listing,"+\n"); break;
+            break;
-    case MINUS: fprintf(listing,"-\n"); break;
+        case LT:
-    case TIMES: fprintf(listing,"*\n"); break;
+            fprintf(listing, "<\n");
-    case OVER: fprintf(listing,"/\n"); break;
+            break;
-    case ENDFILE: fprintf(listing,"EOF\n"); break;
+        case LE:
-    case NUM:
+            fprintf(listing, "<=\n");
-      fprintf(listing,
+            break;
-          "NUM, val= %s\n",tokenString);
+        case GT:
-      break;
+            fprintf(listing, ">\n");
-    case ID:
+            break;
-      fprintf(listing,
+        case GE:
-          "ID, name= %s\n",tokenString);
+            fprintf(listing, ">=\n");
-      break;
+            break;
-    case ERROR:
+        case PLUS:
-      fprintf(listing,
+            fprintf(listing, "+\n");
-          "ERROR: %s\n",tokenString);
+            break;
-      break;
+        case MINUS:
-    default: /* should never happen */
+            fprintf(listing, "-\n");
-      fprintf(listing,"Unknown token: %d\n",token);
+            break;
-  }
+        case TIMES:
            fprintf(listing, "*\n");
            break;
        case OVER:
            fprintf(listing, "/\n");
            break;
        case LPAREN:
            fprintf(listing, "(\n");
            break;
        case RPAREN:
            fprintf(listing, ")\n");
            break;
        case LBRACE:
            fprintf(listing, "[\n");
            break;
        case RBRACE:
            fprintf(listing, "]\n");
            break;
        case LCURLY:
            fprintf(listing, "{\n");
            break;
        case RCURLY:
            fprintf(listing, "}\n");
            break;
        case SEMI:
            fprintf(listing, ";\n");
            break;
        case COMMA:
            fprintf(listing, ",\n");
            break;
        case ENDFILE:
            fprintf(listing, "EOF\n");
            break;
        case NUM:
            fprintf(listing,
                    "NUM, val= %s\n", tokenString);
            break;
        case ID:
            fprintf(listing,
                    "ID, name= %s\n", tokenString);
            break;
        case ERROR:
            fprintf(listing,
                    "ERROR: %s\n", tokenString);
            break;
        default: /* should never happen */
            fprintf(listing, "Unknown token: %d\n", token);
    }
 }
 /* Function newStmtNode creates a new statement
 * node for syntax tree construction
 */
-TreeNode * newStmtNode(StmtKind kind)
+TreeNode *newStmtNode(StmtKind kind) {
-{ TreeNode * t = (TreeNode *) malloc(sizeof(TreeNode));
+    TreeNode *t = (TreeNode *) malloc(sizeof(TreeNode));
-  int i;
+    int i;
-  if (t==NULL)
+    if (t == NULL)
-    fprintf(listing,"Out of memory error at line %d\n",lineno);
+        fprintf(listing, "Out of memory error at line %d\n", lineno);
-  else {
+    else {
-    for (i=0;i<MAXCHILDREN;i++) t->child[i] = NULL;
+        for (i = 0; i < MAXCHILDREN; i++) t->child[i] = NULL;
-    t->sibling = NULL;
+        t->sibling = NULL;
-    t->nodekind = StmtK;
+        t->nodekind = StmtK;
-    t->kind.stmt = kind;
+        t->kind.stmt = kind;
-    t->lineno = lineno;
+        t->lineno = lineno;
-  }
+    }
-  return t;
+    return t;
 }
 /* Function newExpNode creates a new expression 
 * node for syntax tree construction
 */
-TreeNode * newExpNode(ExpKind kind)
+TreeNode *newExpNode(ExpKind kind) {
-{ TreeNode * t = (TreeNode *) malloc(sizeof(TreeNode));
+    TreeNode *t = (TreeNode *) malloc(sizeof(TreeNode));
-  int i;
+    int i;
-  if (t==NULL)
+    if (t == NULL)
-    fprintf(listing,"Out of memory error at line %d\n",lineno);
+        fprintf(listing, "Out of memory error at line %d\n", lineno);
-  else {
+    else {
-    for (i=0;i<MAXCHILDREN;i++) t->child[i] = NULL;
+        for (i = 0; i < MAXCHILDREN; i++) t->child[i] = NULL;
-    t->sibling = NULL;
+        t->sibling = NULL;
-    t->nodekind = ExpK;
+        t->nodekind = ExpK;
-    t->kind.exp = kind;
+        t->kind.exp = kind;
-    t->lineno = lineno;
+        t->lineno = lineno;
-    t->type = Void;
+        t->type = Void;
-  }
+    }
-  return t;
+    return t;
 }
 TreeNode *newDeclNode(DeclKind kind) {
    TreeNode *t = (TreeNode *) malloc(sizeof(TreeNode));
    int i;
    if (t == NULL)
        fprintf(listing, "Out of memory error at line %d\n", lineno);
    else {
        for (i = 0; i < MAXCHILDREN; i++) t->child[i] = NULL;
        t->sibling = NULL;
        t->nodekind = DeclK;
        t->kind.decl = kind;
        t->lineno = lineno;
    }
    return t;
 }
 TreeNode *newTypeNode(TypeKind kind) {
    TreeNode *t = (TreeNode *) malloc(sizeof(TreeNode));
    int i;
    if (t == NULL)
        fprintf(listing, "Out of memory error at line %d\n", lineno);
    else {
        for (i = 0; i < MAXCHILDREN; i++) t->child[i] = NULL;
        t->sibling = NULL;
        t->nodekind = TypeK;
        t->kind.type = kind;
        t->lineno = lineno;
    }
    return t;
 }
 /* Function copyString allocates and makes a new
 * copy of an existing string
 */
-char * copyString(char * s)
+char *copyString(char *s) {
-{ int n;
+    int n;
-  char * t;
+    char *t;
-  if (s==NULL) return NULL;
+    if (s == NULL) return NULL;
-  n = strlen(s)+1;
+    n = strlen(s) + 1;
-  t = malloc(n);
+    t = malloc(n);
-  if (t==NULL)
+    if (t == NULL)
-    fprintf(listing,"Out of memory error at line %d\n",lineno);
+        fprintf(listing, "Out of memory error at line %d\n", lineno);
-  else strcpy(t,s);
+    else
-  return t;
+        strcpy(t, s);
    return t;
 }
 /* Variable indentno is used by printTree to
 * store current number of spaces to indent
 */
-static indentno = 0;
+static int indentno = 0;
 /* macros to increase/decrease indentation */
-#define INDENT indentno+=2
+#define INDENT indentno += 2
-#define UNINDENT indentno-=2
+#define UNINDENT indentno -= 2
 /* printSpaces indents by printing spaces */
-static void printSpaces(void)
+static void printSpaces(void) {
-{ int i;
+    int i;
-  for (i=0;i<indentno;i++)
+    for (i = 0; i < indentno; i++)
-    fprintf(listing," ");
+        fprintf(listing, " ");
 }
 void printType(TreeNode *tree) {
    switch (tree->type) {
        case Void:
            fprintf(listing, "void");
            break;
        case Integer:
            fprintf(listing, "int");
            break;
        case IntegerArray:
            fprintf(listing, "int[]");
            break;
        default:
            return;
    }
 }
 /* procedure printTree prints a syntax tree to the 
 * listing file using indentation to indicate subtrees
 */
-void printTree( TreeNode * tree )
+void printTree(TreeNode *tree) {
-{ int i;
+    int i;
-  INDENT;
+    INDENT;
-  while (tree != NULL) {
+    while (tree != NULL) {
-    printSpaces();
+        printSpaces();
-    if (tree->nodekind==StmtK)
+        if (tree->nodekind == StmtK) {
-    { switch (tree->kind.stmt) {
+            switch (tree->kind.stmt) {
-        case IfK:
+                case CompK:
-          fprintf(listing,"If\n");
+                    fprintf(listing, "Compound Statement:\n");
-          break;
+                    break;
-        case RepeatK:
+                case IfK:
-          fprintf(listing,"Repeat\n");
+                    fprintf(listing, "%s:\n", 
-          break;
+                        (tree->child[2] != NULL) ? "If-Else Statement" : "If Statement");
-        case AssignK:
+                    break;
-          fprintf(listing,"Assign to: %s\n",tree->attr.name);
+                case IterK:
-          break;
+                    fprintf(listing, "While Statement:\n");
-        case ReadK:
+                    break;
-          fprintf(listing,"Read: %s\n",tree->attr.name);
+                case ReturnK:
-          break;
+                    fprintf(listing, "Return Statement:\n");
-        case WriteK:
+                    break;
-          fprintf(listing,"Write\n");
+                default:
-          break;
+                    fprintf(listing, "Unknown StmtNode kind\n");
-        default:
+                    break;
-          fprintf(listing,"Unknown ExpNode kind\n");
+            }
-          break;
+        } else if (tree->nodekind == ExpK) {
-      }
+            switch (tree->kind.exp) {
                case AssignK:
                    fprintf(listing, "Assign:\n");
                    break;
                case OpK:
                    fprintf(listing, "Op: ");
                    printToken(tree->attr.op, "\0");
                    break;
                case ConstK:
                    fprintf(listing, "Const: %d\n", tree->attr.val);
                    break;
                case IdK:
                    fprintf(listing, "Variable: name = %s\n", tree->attr.name);
                    break;
                case ArrIdK:
                    fprintf(listing, "Variable: name = %s\n", tree->attr.name);
                    break;
                case CallK:
                    fprintf(listing, "Call: function name = %s\n", tree->attr.name);
                    break;
                default:
                    fprintf(listing, "Unknown ExpNode kind\n");
                    break;
            }
        } else if (tree->nodekind == DeclK) {
            switch (tree->kind.decl) {
                case FuncK:
                    fprintf(listing, "Function Declaration: name = %s, return type = ", tree->attr.name);
                    printType(tree);
                    fprintf(listing, "\n");
                    break;
                case VarK:
                    fprintf(listing, "Variable Declaration: name = %s, type = ", tree->attr.name);
                    printType(tree);
                    fprintf(listing, "\n");
                    break;
                case ArrVarK:
                    fprintf(listing, "Variable Declaration: name = %s, type = ", tree->attr.name);
                    printType(tree);
                    fprintf(listing, "\n");
                    break;
                case NonArrParamK:
                    if (tree->type == Void)
                        fprintf(listing, "Void Parameter\n");
                    else {
                        fprintf(listing, "Parameter: name = %s, type = ", tree->attr.name);
                        printType(tree);
                        fprintf(listing, "\n");
                    }
                    break;
                case ArrParamK:
                    fprintf(listing, "Parameter: name = %s, type = ", tree->attr.name);
                    printType(tree);
                    fprintf(listing, "\n");
                    break;
                default:
                    fprintf(listing, "Unknown DeclNode kind\n");
                    break;
            }
        } else if (tree->nodekind == TypeK) {
        } else
            fprintf(listing, "Unknown node kind\n");
        for (i = 0; i < MAXCHILDREN; i++)
            printTree(tree->child[i]);
        tree = tree->sibling;
    }
-    else if (tree->nodekind==ExpK)
+    UNINDENT;
    { switch (tree->kind.exp) {
        case OpK:
          fprintf(listing,"Op: ");
          printToken(tree->attr.op,"\0");
          break;
        case ConstK:
          fprintf(listing,"Const: %d\n",tree->attr.val);
          break;
        case IdK:
          fprintf(listing,"Id: %s\n",tree->attr.name);
          break;
        default:
          fprintf(listing,"Unknown ExpNode kind\n");
          break;
      }
    }
    else fprintf(listing,"Unknown node kind\n");
    for (i=0;i<MAXCHILDREN;i++)
         printTree(tree->child[i]);
    tree = tree->sibling;
  }
  UNINDENT;
 }
--- a/src/util.h
+++ b/src/util.h
@@ -25,6 +25,10 @@ TreeNode * newStmtNode(StmtKind);
 */
 TreeNode * newExpNode(ExpKind);
 TreeNode* newDeclNode(DeclKind);
 TreeNode* newTypeNode(TypeKind);
 /* Function copyString allocates and makes a new
 * copy of an existing string
 */
--- a/src/yacc/globals.h
+++ b/src/yacc/globals.h
@@ -1,120 +0,0 @@
 /****************************************************/
 /* File: globals.h                                  */
 /* Yacc/Bison Version                               */
 /* Global types and vars for TINY compiler          */
 /* must come before other include files             */
 /* Compiler Construction: Principles and Practice   */
 /* Kenneth C. Louden                                */
 /****************************************************/
 #ifndef _GLOBALS_H_
 #define _GLOBALS_H_
 #include <stdio.h>
 #include <stdlib.h>
 #include <ctype.h>
 #include <string.h>
 /* Yacc/Bison generates internally its own values
 * for the tokens. Other files can access these values
 * by including the tab.h file generated using the
 * Yacc/Bison option -d ("generate header")
 *
 * The YYPARSER flag prevents inclusion of the tab.h
 * into the Yacc/Bison output itself
 */
 #ifndef YYPARSER
 /* the name of the following file may change */
 #include "y.tab.h"
 /* ENDFILE is implicitly defined by Yacc/Bison,
 * and not included in the tab.h file
 */
 #define ENDFILE 0
 #endif
 #ifndef FALSE
 #define FALSE 0
 #endif
 #ifndef TRUE
 #define TRUE 1
 #endif
 /* MAXRESERVED = the number of reserved words */
 #define MAXRESERVED 8
 /* Yacc/Bison generates its own integer values
 * for tokens
 */
 typedef int TokenType; 
 extern FILE* source; /* source code text file */
 extern FILE* listing; /* listing output text file */
 extern FILE* code; /* code text file for TM simulator */
 extern int lineno; /* source line number for listing */
 /**************************************************/
 /***********   Syntax tree for parsing ************/
 /**************************************************/
 typedef enum {StmtK,ExpK} NodeKind;
 typedef enum {IfK,RepeatK,AssignK,ReadK,WriteK} StmtKind;
 typedef enum {OpK,ConstK,IdK} ExpKind;
 /* ExpType is used for type checking */
 typedef enum {Void,Integer,Boolean} ExpType;
 #define MAXCHILDREN 3
 typedef struct treeNode
   { struct treeNode * child[MAXCHILDREN];
     struct treeNode * sibling;
     int lineno;
     NodeKind nodekind;
     union { StmtKind stmt; ExpKind exp;} kind;
     union { TokenType op;
             int val;
             char * name; } attr;
     ExpType type; /* for type checking of exps */
   } TreeNode;
 /**************************************************/
 /***********   Flags for tracing       ************/
 /**************************************************/
 /* EchoSource = TRUE causes the source program to
 * be echoed to the listing file with line numbers
 * during parsing
 */
 extern int EchoSource;
 /* TraceScan = TRUE causes token information to be
 * printed to the listing file as each token is
 * recognized by the scanner
 */
 extern int TraceScan;
 /* TraceParse = TRUE causes the syntax tree to be
 * printed to the listing file in linearized form
 * (using indents for children)
 */
 extern int TraceParse;
 /* TraceAnalyze = TRUE causes symbol table inserts
 * and lookups to be reported to the listing file
 */
 extern int TraceAnalyze;
 /* TraceCode = TRUE causes comments to be written
 * to the TM code file as code is generated
 */
 extern int TraceCode;
 /* Error = TRUE prevents further passes if an error occurs */
 extern int Error; 
 #endif
--- a/src/yacc/tiny.y
+++ b/src/yacc/tiny.y
@@ -1,164 +0,0 @@
 /****************************************************/
 /* File: tiny.y                                     */
 /* The TINY Yacc/Bison specification file           */
 /* Compiler Construction: Principles and Practice   */
 /* Kenneth C. Louden                                */
 /****************************************************/
 %{
 #define YYPARSER /* distinguishes Yacc output from other code files */
 #include "globals.h"
 #include "util.h"
 #include "scan.h"
 #include "parse.h"
 #define YYSTYPE TreeNode *
 static char * savedName; /* for use in assignments */
 static int savedLineNo;  /* ditto */
 static TreeNode * savedTree; /* stores syntax tree for later return */
 static int yylex(void); // added 11/2/11 to ensure no conflict with lex
 %}
 %token IF THEN ELSE END REPEAT UNTIL READ WRITE
 %token ID NUM 
 %token ASSIGN EQ LT PLUS MINUS TIMES OVER LPAREN RPAREN SEMI
 %token ERROR 
 %% /* Grammar for TINY */
 program     : stmt_seq
                 { savedTree = $1;} 
            ;
 stmt_seq    : stmt_seq SEMI stmt
                 { YYSTYPE t = $1;
                   if (t != NULL)
                   { while (t->sibling != NULL)
                        t = t->sibling;
                     t->sibling = $3;
                     $$ = $1; }
                     else $$ = $3;
                 }
            | stmt  { $$ = $1; }
            ;
 stmt        : if_stmt { $$ = $1; }
            | repeat_stmt { $$ = $1; }
            | assign_stmt { $$ = $1; }
            | read_stmt { $$ = $1; }
            | write_stmt { $$ = $1; }
            | error  { $$ = NULL; }
            ;
 if_stmt     : IF exp THEN stmt_seq END
                 { $$ = newStmtNode(IfK);
                   $$->child[0] = $2;
                   $$->child[1] = $4;
                 }
            | IF exp THEN stmt_seq ELSE stmt_seq END
                 { $$ = newStmtNode(IfK);
                   $$->child[0] = $2;
                   $$->child[1] = $4;
                   $$->child[2] = $6;
                 }
            ;
 repeat_stmt : REPEAT stmt_seq UNTIL exp
                 { $$ = newStmtNode(RepeatK);
                   $$->child[0] = $2;
                   $$->child[1] = $4;
                 }
            ;
 assign_stmt : ID { savedName = copyString(tokenString);
                   savedLineNo = lineno; }
              ASSIGN exp
                 { $$ = newStmtNode(AssignK);
                   $$->child[0] = $4;
                   $$->attr.name = savedName;
                   $$->lineno = savedLineNo;
                 }
            ;
 read_stmt   : READ ID
                 { $$ = newStmtNode(ReadK);
                   $$->attr.name =
                     copyString(tokenString);
                 }
            ;
 write_stmt  : WRITE exp
                 { $$ = newStmtNode(WriteK);
                   $$->child[0] = $2;
                 }
            ;
 exp         : simple_exp LT simple_exp 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = LT;
                 }
            | simple_exp EQ simple_exp
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = EQ;
                 }
            | simple_exp { $$ = $1; }
            ;
 simple_exp  : simple_exp PLUS term 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = PLUS;
                 }
            | simple_exp MINUS term
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = MINUS;
                 } 
            | term { $$ = $1; }
            ;
 term        : term TIMES factor 
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = TIMES;
                 }
            | term OVER factor
                 { $$ = newExpNode(OpK);
                   $$->child[0] = $1;
                   $$->child[1] = $3;
                   $$->attr.op = OVER;
                 }
            | factor { $$ = $1; }
            ;
 factor      : LPAREN exp RPAREN
                 { $$ = $2; }
            | NUM
                 { $$ = newExpNode(ConstK);
                   $$->attr.val = atoi(tokenString);
                 }
            | ID { $$ = newExpNode(IdK);
                   $$->attr.name =
                         copyString(tokenString);
                 }
            | error { $$ = NULL; }
            ;
 %%
 int yyerror(char * message)
 { fprintf(listing,"Syntax error at line %d: %s\n",lineno,message);
  fprintf(listing,"Current token: ");
  printToken(yychar,tokenString);
  Error = TRUE;
  return 0;
 }
 /* yylex calls getToken to make Yacc/Bison output
 * compatible with ealier versions of the TINY scanner
 */
 static int yylex(void)
 { return getToken(); }
 TreeNode * parse(void)
 { yyparse();
  return savedTree;
 }
Author	SHA1	Message	Date
yenru0	48cafc8815	add semantic paper	2025-12-05 02:29:14 +09:00
yenru0	f524a9e165	fix parser and semantic v2.2	2025-12-05 02:09:12 +09:00
yenru0	d46fd36bcb	fix parse and semantic v2.1	2025-12-05 00:47:51 +09:00
yenru0	2b6193a2c7	semi-complete semantic v2	2025-12-03 04:58:41 +09:00
yenru0	90b7d8fcbe	add child_count to scope	2025-12-03 01:57:47 +09:00
yenru0	4e2fdf88f9	fix semantic for printing or sth	2025-12-03 01:53:05 +09:00
yenru0	75407304f8	fix output format	2025-12-02 14:35:38 +09:00
yenru0	f1fd203233	semi-complete semantic	2025-12-02 05:11:27 +09:00
yenru0	f4501529df	modify symtab.h struct naming	2025-12-01 16:55:56 +09:00
yenru0	1840ea6b74	improve symtab.h signature	2025-12-01 15:22:05 +09:00
yenru0	1204abb4f9	some changes to cminus for symtab	2025-12-01 03:35:09 +09:00
yenru0	a9855535cb	add P4.pdf	2025-11-28 21:11:58 +09:00
yenru0	2d185ee8ee	add syntax	2025-11-28 20:12:51 +09:00
yenru0	1f7026bda8	add L11, L12 pdf	2025-11-27 09:40:52 +09:00
yenru0	d14d440d14	modify L9 pdf add L10 pdf	2025-11-20 09:15:17 +09:00
yenru0	807ac03a6e	complement in 11.13	2025-11-13 10:10:10 +09:00
yenru0	d39f272563	complement in 11.11	2025-11-11 14:11:28 +09:00
yenru0	d83964a190	add L8.pdf and complement in 11.06	2025-11-06 10:14:44 +09:00
yenru0	9de6b3a02d	complement notes in 11.04	2025-11-05 11:14:03 +09:00
yenru0	0f3b235e99	add L6.pdf and complement in 10.30	2025-10-30 09:58:04 +09:00
yenru0	2a7cb64862	update notes in midterm2	2025-10-27 17:19:12 +09:00
yenru0	13b27cc21e	update notes in midterm1	2025-10-27 04:25:46 +09:00
yenru0	4a11a52f1a	update style	2025-10-27 04:25:17 +09:00
yenru0	13eaf5bdba	add P3.pdf	2025-10-26 18:45:53 +09:00
yenru0	517c03837b	complement notes in 10.16	2025-10-16 10:05:22 +09:00
yenru0	30027b6b4c	complement notes 10.14	2025-10-14 14:00:50 +09:00
yenru0	7b07687528	fix cminus.l	2025-10-03 21:06:09 +09:00
yenru0	e955ec672b	add crossnote and mv textfile	2025-10-03 19:17:46 +09:00
yenru0	add7307893	input() return 0 when EOF after flex 2.6	2025-10-03 19:17:20 +09:00
yenru0	cb19f33fef	fix scan.c for ID accept non-alphabet characters and resolve some warning	2025-10-03 16:59:36 +09:00
yenru0	c86334621d	update gitignore	2025-10-03 14:27:12 +09:00
yenru0	444f5ef941	reformat scan.c	2025-10-03 14:16:17 +09:00
yenru0	bd5426c709	add cminus.l	2025-10-03 14:06:47 +09:00
yenru0	844f29a803	update test case	2025-10-02 10:50:33 +09:00
yenru0	cc3de91036	fix scan.c not to transition to INNE	2025-10-02 10:50:16 +09:00
yenru0	f9a5bcf4b2	complement notes in 10.02	2025-10-02 10:07:21 +09:00
yenru0	9af73c5a15	implement lexical analysis function for c-minus	2025-10-02 07:14:04 +09:00
yenru0	87931e8cc2	complement in 9.25	2025-09-25 10:58:48 +09:00
yenru0	3acbb7e1e6	complement in 9.18	2025-09-18 10:31:12 +09:00
yenru0	b790a4faa0	move .md to notes/.md and add lecture pdf	2025-09-18 09:35:37 +09:00
		`@@ -1,3 +0,0 @@`
			`[attr]lfs-file filter=lfs diff=lfs merge=lfs -text`

			`*.pdf lfs-file`