Add list length primitive to runtime environment

include/cherry/primitives.h

@@ -19,18 +19,15 @@
 
 #include "cherry/runtime.h"
 
-#define DECLARE_FUN(Name) \
-  struct org_cherry_value* Name(struct org_cherry_environment* env, struct org_cherry_value* args)
-
 // org.cherry.core
 struct org_cherry_value*    org_cherry_core_type(struct org_cherry_environment* env, struct org_cherry_value* args);
 struct org_cherry_value*    org_cherry_core_raise(struct org_cherry_environment* env, struct org_cherry_value* args);
 
 struct org_cherry_value*    org_cherry_core_cons(struct org_cherry_environment* env, struct org_cherry_value* args);
 struct org_cherry_value*    org_cherry_core_list(struct org_cherry_environment* env, struct org_cherry_value* args);
-
-DECLARE_FUN(org_cherry_core_head);
-DECLARE_FUN(org_cherry_core_tail);
+struct org_cherry_value*    org_cherry_core_head(struct org_cherry_environment* env, struct org_cherry_value* args);
+struct org_cherry_value*    org_cherry_core_tail(struct org_cherry_environment* env, struct org_cherry_value* args);
+struct org_cherry_value*    org_cherry_core_length(struct org_cherry_environment* env, struct org_cherry_value* args);
 
 struct org_cherry_value*    org_cherry_core_tuple(struct org_cherry_environment* env, struct org_cherry_value* args);
 

include/cherry/runtime.h

@@ -202,6 +202,8 @@ extern struct org_cherry_value*         org_cherry_symbol_catch;
 #define IS_SELF_EVALUATING(value) \
   (IS_BOOLEAN(value) || IS_FIXNUM(value) || IS_CHAR(value) || IS_STRING(value) || IS_FLOAT(value))
 
+#define IS_LIST(obj) (IS_PAIR(obj) || IS_NULL(obj))
+
 #define IS_VARIABLE(value) \
   IS_SYMBOL(value)
 

source/primitives/core.c

@@ -87,6 +87,23 @@ org_cherry_core_tail(struct org_cherry_environment* env, struct org_cherry_value
 }
 
 
+struct org_cherry_value*
+org_cherry_core_length(struct org_cherry_environment* env, struct org_cherry_value* args)
+{
+	if(IS_NULL(args) || !IS_LIST(HEAD(args)))
+		org_cherry_env_raise(env, org_cherry_string("no list is given for the first operand"));
+
+	struct org_cherry_value* lst = HEAD(args);
+	cy_fixnum_t length = 0;
+
+	while(!IS_NULL(lst)) {
+		length++;
+		lst = TAIL(lst);
+	}
+
+	return org_cherry_fixnum(length);
+}
+
 
 
 struct org_cherry_value*

source/runtime.c

@@ -97,6 +97,7 @@ org_cherry_environment(void)
 	proc_to_env(env, "list", org_cherry_core_list);
 	proc_to_env(env, "head", org_cherry_core_head);
 	proc_to_env(env, "tail", org_cherry_core_tail);
+	proc_to_env(env, "length", org_cherry_core_length);
 	proc_to_env(env, "tuple", org_cherry_core_tuple);
 	proc_to_env(env, "exit", org_cherry_system_exit);