mem.c

   1 #include <stdlib.h>
   2 #include "lambda.h"
   3 #include "print.h"
   4
   5 void lambda_free(struct lambda *t)
   6 {
   7         if(t != NULL){
   8                 if(t->refcount == 1){
   9                         switch(t->which){
  10                         case lambda_ident:
  11                                 free(t->data.identifier.ident);
  12                                 break;
  13                         case lambda_abs:
  14                                 free(t->data.abstraction.ident);
  15                                 lambda_free(t->data.abstraction.expr);
  16                                 break;
  17                         case lambda_app:
  18                                 lambda_free(t->data.application.expr1);
  19                                 lambda_free(t->data.application.expr2);
  20                                 break;
  21                         }
  22                         free(t);
  23                 } else {
  24                         t->refcount--;
  25                 }
  26         }
  27 }
  28
  29 void binding_replace(struct lambda *b, struct lambda *from, struct lambda *to)
  30 {
  31         switch(b->which){
  32         case lambda_ident:
  33                 if(b->data.identifier.binding == from)
  34                         b->data.identifier.binding = to;
  35                 break;
  36         case lambda_abs:
  37                 binding_replace(b->data.abstraction.expr, from, to);
  38                 break;
  39         case lambda_app:
  40                 binding_replace(b->data.application.expr1, from, to);
  41                 binding_replace(b->data.application.expr2, from, to);
  42                 break;
  43         }
  44 }
  45
  46 struct lambda *copy(struct lambda *t)
  47 {
  48         struct lambda *c = make_lambda();
  49         c->which = t->which;
  50         switch(t->which){
  51         case lambda_ident:
  52                 c->data.identifier.ident = strdup(t->data.identifier.ident);
  53                 c->data.identifier.binding = t->data.identifier.binding;
  54                 break;
  55         case lambda_abs:
  56                 c->data.abstraction.ident = strdup(t->data.abstraction.ident);
  57                 c->data.abstraction.strict = t->data.abstraction.strict;
  58                 c->data.abstraction.expr = copy(t->data.abstraction.expr);
  59                 binding_replace(c->data.abstraction.expr, t, c);
  60                 break;
  61         case lambda_app:
  62                 c->data.application.expr1 = copy(t->data.application.expr1);
  63                 c->data.application.expr2 = copy(t->data.application.expr2);
  64                 break;
  65         }
  66         return c;
  67 }