ast.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3
   4 #include "ast.h"
   5
   6 struct ast *ast_alloc()
   7 {
   8         struct ast *res = malloc(sizeof(struct ast));
   9         if (res == NULL) {
  10                 perror("malloc");
  11                 exit(1);
  12         }
  13         return res;
  14 }
  15
  16 struct ast *ast_cons(struct ast *el, struct ast *tail)
  17 {
  18         struct ast *res = ast_alloc();
  19         res->type = an_cons;
  20         res->data.an_cons.el = el;
  21         res->data.an_cons.tail = tail;
  22         return res;
  23 }
  24
  25 struct ast *ast_binop(struct ast *l, enum binop op, struct ast *r)
  26 {
  27         struct ast *res = ast_alloc();
  28         res->type = an_binop;
  29         res->data.an_binop.l = l;
  30         res->data.an_binop.op = op;
  31         res->data.an_binop.r = r;
  32         return res;
  33 }
  34
  35 struct ast *ast_int(int integer)
  36 {
  37         struct ast *res = ast_alloc();
  38         res->type = an_int;
  39         res->data.an_int = integer;
  40         return res;
  41 }
  42
  43 static const char *binop_str[] = {
  44         [plus] = "+",
  45         [minus] = "+",
  46         [times] = "+",
  47         [divide] = "+",
  48 };
  49
  50 void ast_print(struct ast * ast, FILE *out)
  51 {
  52         if (ast == NULL)
  53                 return;
  54         switch(ast->type) {
  55         case an_binop:
  56                 fprintf(out, "(");
  57                 ast_print(ast->data.an_binop.l, out);
  58                 fprintf(out, "%s", binop_str[ast->data.an_binop.op]);
  59                 ast_print(ast->data.an_binop.r, out);
  60                 fprintf(out, ")");
  61                 break;
  62         case an_cons:
  63                 ast_print(ast->data.an_cons.el, out);
  64                 fprintf(out, ";\n");
  65                 ast_print(ast->data.an_cons.tail, out);
  66                 break;
  67         case an_int:
  68                 fprintf(out, "%d", ast->data.an_int);
  69                 break;
  70         default:
  71                 fprintf(stderr, "Unsupported AST node\n");
  72                 exit(1);
  73         }
  74 }
  75
  76 void ast_free(struct ast *ast)
  77 {
  78         if (ast == NULL)
  79                 return;
  80         switch(ast->type) {
  81         case an_binop:
  82                 ast_free(ast->data.an_binop.l);
  83                 ast_free(ast->data.an_binop.r);
  84                 break;
  85         case an_cons:
  86                 ast_free(ast->data.an_cons.el);
  87                 ast_free(ast->data.an_cons.tail);
  88                 break;
  89         case an_int:
  90                 break;
  91         default:
  92                 fprintf(stderr, "Unsupported AST node\n");
  93                 exit(1);
  94         }
  95         free(ast);
  96 }