_EnvironmentNode* next;
};
-struct Environment;
-typedef struct Environment Environment;
struct Environment {
+ size_t referenceCount;
+ Environment* shadowed;
_EnvironmentNode* top;
};
Object result;
};
-void Environment_initialize(Environment* self) {
+void Environment_initialize(Environment* self, Environment* shadowed) {
+ self->referenceCount = 1;
+ self->shadowed = shadowed;
self->top = NULL;
}
void Environment_deinitialize(Environment* self) {
+ assert(self->referenceCount == 0);
+
while(self->top != NULL) {
_EnvironmentNode* en = self->top;
self->top = en->next;
}
}
-Environment* Environment_construct() {
+Environment* Environment_construct(Environment* shadowed) {
Environment* result = malloc(sizeof(Environment));
- Environment_initialize(result);
+ Environment_initialize(result, shadowed);
return result;
}
+Environment* Environment_reference(Environment* self) {
+ self->referenceCount++; // TODO Do we need to make this thread safe?
+ return self;
+}
+
void Environment_destruct(Environment* self) {
- Environment_deinitialize(self);
- free(self);
+ self->referenceCount--; // TODO Do we need to make this thread safe?
+ if(self->referenceCount == 0) {
+ Environment_deinitialize(self);
+ free(self);
+ }
}
-Environment_get_Result Environment_get(Environment* self, char* symbol) {
+Environment_get_Result Environment_getShallow(Environment* self, char* symbol) {
for(_EnvironmentNode* current = self->top; current != NULL; current = current->next) {
if(strcmp(current->symbol, symbol) == 0) {
return (Environment_get_Result) { true, current->value };
return (Environment_get_Result) { false, BUILTIN_NIL };
}
+Environment_get_Result Environment_get(Environment* self, char* symbol) {
+ for(; self != NULL; self = self->shadowed) {
+ Environment_get_Result result = Environment_getShallow(self, symbol);
+ if(result.found) return result;
+ }
+ return (Environment_get_Result) { false, BUILTIN_NIL };
+}
+
void Environment_set(Environment* self, char* symbol, Object value) {
- assert(!(Environment_get(self, symbol).found));
+ assert(!(Environment_getShallow(self, symbol).found));
_EnvironmentNode* en = malloc(sizeof(_EnvironmentNode));
en->symbol = symbol;