Add named let as loop to cherry.

bootstrap/bootstrap.h

@@ -186,6 +186,7 @@ extern struct cherry_value*         cherry_symbol_define;
 extern struct cherry_value*         cherry_symbol_let;
 extern struct cherry_value*         cherry_symbol_lambda;
 extern struct cherry_value*         cherry_symbol_if;
+extern struct cherry_value*         cherry_symbol_loop;
 
 extern struct cherry_value*         cherry_symbol_begin;
 extern struct cherry_value*         cherry_symbol_try;
@@ -251,6 +252,9 @@ struct cherry_value*    cherry_system_exit(struct cherry_environment* env, struc
 #define IS_LAMBDA(value) \
   IS_TAGGED(value, cherry_symbol_lambda)
 
+#define IS_LOOP(value) \
+  IS_TAGGED(value, cherry_symbol_loop)
+
 #define IS_BEGIN(value) \
   IS_TAGGED(value, cherry_symbol_begin)
 

bootstrap/read.c

@@ -689,7 +689,7 @@ cherry_read_pair(struct cherry_context* context)
 	head = cherry_read(context);
 	tail = cherry_read_pair(context);
 
-	return (struct cherry_value*) cherry_list_cons(head, tail);
+	return cherry_list_cons(head, tail);
 }
 
 static struct cherry_value*
@@ -754,6 +754,32 @@ cherry_transform_if(struct cherry_value* value)
 }
 
 
+static struct cherry_value*
+cherry_transform_loop(struct cherry_value* value)
+{
+	struct cherry_value* name = HEAD(HEAD(value));
+	struct cherry_value* args = cherry_list_reverse(TAIL(HEAD(value)));
+	struct cherry_value* body = TAIL(value);
+
+	struct cherry_value* params = cherry_emptylist;
+	struct cherry_value* values = cherry_emptylist;
+
+	while(!IS_NULL(args)) {
+		struct cherry_value* duo = HEAD(args);
+
+		params = cherry_list_cons(HEAD(duo), params);
+		values = cherry_list_cons(HEAD(TAIL(duo)), values);
+
+		args = TAIL(args);
+	}
+
+	struct cherry_value* lambda = cherry_list_cons(cherry_symbol_lambda, cherry_list_cons(params, body));
+	struct cherry_value* let = cherry_list_cons(cherry_symbol_let, cherry_list_cons(name, cherry_list_cons(lambda, cherry_emptylist)));
+	struct cherry_value* app = cherry_list_cons(name, values);
+
+	return cherry_list_cons(cherry_symbol_begin, cherry_list_cons(let, cherry_list_cons(app, cherry_emptylist)));
+}
+
 static struct cherry_value* 
 cherry_transform(struct cherry_value* value)
 {
@@ -763,7 +789,9 @@ cherry_transform(struct cherry_value* value)
 		return cherry_transform_define(TAIL(value));
 	else if(IS_IF(value))
 		return cherry_transform_if(value);
-	else
+	else if(IS_LOOP(value)) {
+		return cherry_transform_loop(TAIL(value));
+	} else
 		return value;
 }
 
@@ -829,5 +857,6 @@ cherry_read(struct cherry_context* context)
 	return 0;
 
 RETURN_VALUE:
+
 	return cherry_transform(value);
 }

bootstrap/runtime.c

@@ -35,6 +35,7 @@ struct cherry_value*		cherry_symbol_let;
 struct cherry_value*		cherry_symbol_lambda;
 struct cherry_value*		cherry_symbol_if;
 struct cherry_value*		cherry_symbol_quote;
+struct cherry_value*		cherry_symbol_loop;
 
 struct cherry_value*		cherry_symbol_try;
 struct cherry_value*		cherry_symbol_begin;
@@ -66,6 +67,7 @@ cherry_initialize(struct cherry_value* arguments)
 	cherry_symbol_let		= cherry_symbol("let");
 	cherry_symbol_lambda 	= cherry_symbol("lambda");
 	cherry_symbol_if     	= cherry_symbol("if");
+	cherry_symbol_loop     	= cherry_symbol("loop");
 	cherry_symbol_begin   	= cherry_symbol("begin");
 	cherry_symbol_catch   	= cherry_symbol("catch");
 	cherry_symbol_try 		= cherry_symbol("try");