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

   1 struct _EnvironmentNode;
   2 typedef struct _EnvironmentNode _EnvironmentNode;
   3 struct _EnvironmentNode {
   4   const char* symbol;
   5   Object value;
   6   _EnvironmentNode* next;
   7 };
   8
   9 struct Environment {
  10   _EnvironmentNode* top;
  11 };
  12
  13 struct Environment_get_Result;
  14 typedef struct Environment_get_Result Environment_get_Result;
  15 struct Environment_get_Result {
  16   bool found;
  17   Object result;
  18 };
  19
  20 void Environment_initialize(Environment* self) {
  21   self->top = NULL;
  22 }
  23
  24 void Environment_deinitialize(Environment* self) {
  25   while(self->top != NULL) {
  26     _EnvironmentNode* en = self->top;
  27     self->top = en->next;
  28     Object_deinitialize(&(en->value));
  29     free(en);
  30   }
  31 }
  32
  33 Environment* Environment_construct() {
  34   Environment* result = malloc(sizeof(Environment));
  35   Environment_initialize(result);
  36   return result;
  37 }
  38
  39 void Environment_destruct(Environment* self) {
  40   Environment_deinitialize(self);
  41   free(self);
  42 }
  43
  44 Environment_get_Result Environment_get(Environment* self, char* symbol) {
  45   for(_EnvironmentNode* current = self->top; current != NULL; current = current->next) {
  46     if(strcmp(current->symbol, symbol) == 0) {
  47       return (Environment_get_Result) { true, current->value };
  48     }
  49   }
  50   return (Environment_get_Result) { false, BUILTIN_NIL };
  51 }
  52
  53 void Environment_set(Environment* self, char* symbol, Object value) {
  54   assert(!(Environment_get(self, symbol).found));
  55
  56   _EnvironmentNode* en = malloc(sizeof(_EnvironmentNode));
  57   en->symbol = symbol;
  58   en->value = value;
  59   en->next = self->top;
  60   self->top = en;
  61 }