Switch environment to a list of mapping tuples (key, value)

bootstrap/bootstrap.h

@@ -153,19 +153,23 @@ struct value*   list_reverse(struct value* value);
 #define SYMBOL_LEFT(node) HEAD(TAIL(node))
 #define SYMBOL_RIGHT(node) TAIL(TAIL(node))
 
-#define EXTEND_ENV(env) cons(cons(emptylist,emptylist), env)
-#define INITIAL_ENV EXTEND_ENV(emptylist)
+#define EXTEND_ENV(env) cons(emptylist, env)
+#define INITIAL_ENV cons(emptylist, emptylist)
 #define FIRST_FRAME(env) HEAD(env)
 #define PARENT_FRAMES(env) TAIL(env)
-#define FRAME_VARIABLES(frame) HEAD(frame)
-#define FRAME_VALUES(frame) TAIL(frame)
 
 struct value*   environment(void);
 struct value*   env_lookup(struct value* env, struct value* var);
 struct value*   env_set(struct value* env, struct value* var, struct value* val);
 struct value*   env_let(struct value* env, struct value* var, struct value* val);
 
+const byte_t*   from_loadpath(struct value* module);
+struct value*   add_to_loaded_modules(struct value* symbol, struct value* env);
+struct value*   get_loaded_module(struct value* symbol);
+
 extern struct value*    global_symbollist;
+extern struct value*    loaded_modules;
+extern struct ptrarray* loadpath;
 
 extern struct value*         emptylist;
 extern struct value*         True;

bootstrap/runtime.c

@@ -90,19 +90,18 @@ initialize(struct value* arguments)
 struct value*
 env_lookup(struct value* env, struct value* symbol)
 {
-	struct value *frame, *vars, *vals;
+	struct value *frame;
 
 	while(!IS_NULL(env)) {
 		frame = FIRST_FRAME(env);
-		vars = FRAME_VARIABLES(frame);
-		vals = FRAME_VALUES(frame);
 
-		while(!IS_NULL(vars)) {
-			if(symbol == HEAD(vars))
-				return HEAD(vals);
+		while(!IS_NULL(frame)) {
+			struct value* pair = HEAD(frame);
 
-			vars = TAIL(vars);
-			vals = TAIL(vals);
+			if(NTH(pair, 0) == symbol)
+				return NTH(pair, 1);
+
+			frame = TAIL(frame);
 		}
 
 		env = PARENT_FRAMES(env);
@@ -115,21 +114,20 @@ env_lookup(struct value* env, struct value* symbol)
 struct value*
 env_set(struct value* env, struct value* var, struct value* val)
 {
-	struct value *frame, *vars, *vals;
+	struct value *frame;
 
 	while(!IS_NULL(env)) {
 		frame = FIRST_FRAME(env);
-		vars = FRAME_VARIABLES(frame);
-		vals = FRAME_VALUES(frame);
 
-		while(!IS_NULL(vars)) {
-			if(var == HEAD(vars)) {
-				HEAD(vals) = val;
+		while(!IS_NULL(frame)) {
+			struct value* pair = HEAD(frame);
+
+			if(NTH(pair, 0) == var) {
+				NTH(pair, 1) = val;
 				return True;
 			}
 
-			vars = TAIL(vars);
-			vals = TAIL(vals);
+			frame = TAIL(frame);
 		}
 
 		env = PARENT_FRAMES(env);
@@ -142,25 +140,64 @@ struct value*
 env_let(struct value* env, struct value* var, struct value* val)
 {
 	struct value* frame = FIRST_FRAME(env);
-	struct value* vars = FRAME_VARIABLES(frame);
-	struct value* vals = FRAME_VALUES(frame);
 
-	while(!IS_NULL(vars)) {
-		if(var == HEAD(vars)) {
+	while(!IS_NULL(frame)) {
+		struct value* pair = HEAD(frame);
+
+		if(var == NTH(pair, 0)) {
 			failure(0, "Overwrite declaration from variable %s", var->symbol_value);
 		}
 
-		vars = TAIL(vars);
-		vals = TAIL(vals);
+		frame = TAIL(frame);
 	}
 
-	HEAD(frame) = cons(var, HEAD(frame));
-	TAIL(frame) = cons(val, TAIL(frame));
+	FIRST_FRAME(env) = cons(tuple2(var, val), FIRST_FRAME(env));
 
 	return True;
 }
 
 
+const byte_t*
+from_loadpath(struct value* module)
+{
+	size_t module_size = utf8_size(module->symbol_value);
+	byte_t* modulename = GC_MALLOC(sizeof(byte_t) * module_size);
+	byte_t* p;
+
+	memcpy(modulename, module->symbol_value, module_size);
+
+	for(p = modulename; p < modulename + module_size; ++p) {
+		if(*p == '.') 
+			*p = '/';
+	}
+
+	size_t loadpath_size = ptrarray_size(loadpath);
+	size_t i;
+
+	for(i = 0; i < module_size; ++i) {
+		const byte_t* path = (const byte_t*) ptrarray_get(loadpath, i);
+		size_t path_size = utf8_size(path);
+
+		byte_t* full_path = GC_MALLOC(sizeof(byte_t) * (module_size + path_size + 2));
+
+		memcpy(full_path, path, path_size);
+		memcpy(full_path + path_size + 1, modulename, module_size);
+		full_path[path_size] = '/';
+		full_path[path_size + module_size + 1] = '\0';
+
+		FILE* port = fopen(full_path, "rb");
+
+		if(port) {
+			fclose(port);
+			return full_path;
+		}
+	}
+
+	return 0;
+}
+
+
+
 
 struct value*
 core_raise(struct value* env, struct value* args)