code.kerkeslager.com Git - fur/blob - c/environment.c

   1 #ifndef ENVIRONMENT_C
   2 #define ENVIRONMENT_C
   3
   4 #include<assert.h>
   5
   6 struct EnvironmentNode;
   7 typedef struct EnvironmentNode EnvironmentNode;
   8 struct EnvironmentNode {
   9   Symbol* key;
  10   Object* value;
  11   EnvironmentNode* next;
  12 };
  13
  14 struct Environment {
  15   Environment* parent;
  16   EnvironmentNode* root;
  17 };
  18
  19 Environment* Environment_create(Environment* parent) {
  20   Environment* result = malloc(sizeof(Environment));
  21   result->parent = parent;
  22   result->root = NULL;
  23   return result;
  24 }
  25
  26 EnvironmentGetResult Environment_get(Environment* self, Symbol* key) {
  27   if(self == NULL) return (EnvironmentGetResult) { false, NULL };
  28
  29   for(EnvironmentNode* search = self->root; search != NULL; search = search->next) {
  30     if(search->key == key) return (EnvironmentGetResult) { true, search->value };
  31   }
  32
  33   return Environment_get(self->parent, key);
  34 }
  35
  36 bool Environment_set(Environment* self, Symbol* key, Object* value) {
  37   assert(self != NULL);
  38
  39   for(EnvironmentNode* search = self->root; search != NULL; search = search->next) {
  40     if(search->key == key) return false;
  41   }
  42
  43   EnvironmentNode* node = malloc(sizeof(EnvironmentNode));
  44   node->key = key;
  45   node->value = value;
  46   node->next = self->root;
  47   self->root = node;
  48   return true;
  49 }
  50
  51 #endif