smple c interpreter (1)

new:

• global variable support.
• return function value.
• variable can use = to receive function return value.

r2

 1 descent@debianlinux:simple_compiler$ cat test_pattern/p2
 2 int a;
 3 
 4 int f2(int i)
 5 {
 6   1+2;
 7   a=3;
 8   return 2+5+i+a;
 9 }
10 
11 int main()
12 {
13   int x,y;
14   int a;
15 
16   a=99;
17   printf("a: %d\n", a);
18   
19   y=2;
20   x = f2(y+1);
21 
22   printf("f2(): %d\n", x);
23 }
24 
25 
26 descent@debianlinux:simple_compiler$ ./c_parser < test_pattern/p2
27 xx return
28 expr return
29 STRING: a: %d
30 
31 STRING: f2(): %d
32 
33 \tree( root( prog( g_var(a |int |global))( f2 |int |func( para(i |int))( func_body( +(1)(2))( =(a)(3))( return( +( +( +(2)(5))(i))(a)))))( main |int |func( func_body( var(x |int)(y |int))( var(a |int))( =(a)(99))( printf(a: \%d\\n)(a))( =(y)(2))( =(x)( f2( +(y)(1))))( printf(f2\(\): \%d\\n)(x))))(main)))
34  op: root
35 can not handle op: f2, ast type: NAME
36 can not handle op: main, ast type: NAME
37 a: 99
38 f2(): 13