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Author SHA1 Message Date
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
9 changed files with 407 additions and 3 deletions
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71
notes/4.md
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@@ -83,12 +83,12 @@ L -> S | L,S
It can be represented as a NFA: It can be represented as a NFA:
```python {cmd matplotlib} ```python {cmd matplotlib hide}
import sys import sys
import pymupdf import pymupdf
from PIL import Image from PIL import Image
doc = pymupdf.open("../pdf/L4.pdf") doc = pymupdf.open("../pdf/L4.pdf")
pix = doc[22].get_pixmap(dpi=500) pix = doc[22].get_pixmap(dpi=360)
img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples) img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)
plt.imshow(img) plt.imshow(img)
@@ -97,8 +97,73 @@ plt.tight_layout()
plt.show() plt.show()
``` ```
* SLR(1) Parsing
* LR(1) Grammar
```python {cmd matplotlib hide}
import sys
import pymupdf
from PIL import Image
doc = pymupdf.open("../pdf/L4.pdf")
pix = doc[47].get_pixmap(dpi=360)
img = Image.frombytes("RGB", [pix.width, pix.height], pix.samples)
plt.imshow(img)
plt.axis('off')
plt.tight_layout()
plt.show()
```
LR(1) Parsing Table
is same as LR(0) parsing table construction except for reductions:
* LR(1) Grammar * LALR(1) Grammar
LALR(1) generally has the same number of states as SLR (much less than LR(1))
for Pascal language, SLR requires several hundred states, LR(1) requires several thousand states.
#### Ambiguous Grammar
Ambiguity is mainly from
* Precedence
* The production at higher levels will have operators with lower priorities (and vice versa).
* we can insert non-terminals to enforce precendence.
* Associativity
* we should determine where to place recursion depending on the associativity
for example: `if-then-else`
**Automatic Disambiguation**
We can define precedence to use ambiguous grammars w/o shift-reduce conflicts.
## AST
### AST Construction LL
```c
expr parse_S() {
switch(token) {
case num:
case '(':
expr child1 = parse_E();
expr child2 = parse_Sp();
return new S(child1, child2);
default:
parseError();
}
}
```
### AST Construction LR

73
src/res/result.1.txt Normal file
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@@ -0,0 +1,73 @@
C-MINUS COMPILATION: ./test.1.txt
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

77
src/res/result.2.txt Normal file
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@@ -0,0 +1,77 @@
C-MINUS COMPILATION: ./test.2.txt
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

73
src/res/test.1.result.txt Normal file
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@@ -0,0 +1,73 @@
C-MINUS COMPILATION: ./res/test.1.txt
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

16
src/res/test.1.txt Normal file
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@@ -0,0 +1,16 @@
/* 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));
}

77
src/res/test.2.result.txt Normal file
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@@ -0,0 +1,77 @@
C-MINUS COMPILATION: ./res/test.2.txt
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

21
src/res/test.2.txt Normal file
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@@ -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]);
}
}
}

0
src/test.cm → src/res/test.cm
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2
src/scan.c
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@@ -110,6 +110,8 @@ TokenType getToken(void) { /* index for storing into tokenString */
save = FALSE; save = FALSE;
else if (c == '=') else if (c == '=')
state = INASSIGN; state = INASSIGN;
else if(c == '!')
state = INNE;
else if (c == '<') { else if (c == '<') {
state = INLT; state = INLT;
} else if (c == '>') { } else if (c == '>') {