Split functions into many files, remove string from std.

include/function_utils.hpp

@@ -1,5 +1,9 @@
 #pragma once
 
+extern "C" {
+#include "libabacus.h"
+}
+
 #define FUNCTION(name) libab_result function_##name( \
         libab* ab, libab_ref* scope, libab_ref_vec* params, libab_ref* into)
 

include/functions.hpp

@@ -1,44 +1,5 @@
 #pragma once
 
-#include "ref.hpp"
-#include "util.hpp"
-#include "function_utils.hpp"
-extern "C" {
-#include "libabacus.h"
-}
-
-FUNCTION(print_string);
-FUNCTION(to_string_num);
-FUNCTION(to_string_bool);
-FUNCTION(to_string_unit);
-
-FUNCTION(plus);
-FUNCTION(minus);
-FUNCTION(times);
-FUNCTION(divide);
-FUNCTION(pow);
-
-FUNCTION(lt);
-FUNCTION(lte);
-FUNCTION(equals);
-FUNCTION(gt);
-FUNCTION(gte);
-
-FUNCTION(negate);
-FUNCTION(factorial);
-
-FUNCTION(ln);
-FUNCTION(exp);
-
-FUNCTION(sqrt);
-
-FUNCTION(sin);
-FUNCTION(cos);
-FUNCTION(tan);
-
-FUNCTION(arcsin);
-FUNCTION(arccos);
-FUNCTION(arctan);
-
-FUNCTION(quit);
-FUNCTION(request_precision);
+#include "operator_functions.hpp"
+#include "other_functions.hpp"
+#include "trig_functions.hpp"

include/operator_functions.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "function_utils.hpp"
+
+FUNCTION(plus);
+FUNCTION(minus);
+FUNCTION(times);
+FUNCTION(divide);
+FUNCTION(pow);
+
+FUNCTION(lt);
+FUNCTION(lte);
+FUNCTION(equals);
+FUNCTION(gt);
+FUNCTION(gte);
+
+FUNCTION(negate);
+FUNCTION(factorial);

include/other_functions.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "function_utils.hpp"
+
+FUNCTION(ln);
+FUNCTION(exp);
+
+FUNCTION(sqrt);

include/repl_functions.hpp

@@ -0,0 +1,6 @@
+#pragma once
+
+#include "function_utils.hpp"
+
+FUNCTION(quit);
+FUNCTION(request_precision);

include/string_functions.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include "function_utils.hpp"
+
+FUNCTION(print_string);
+FUNCTION(to_string_num);
+FUNCTION(to_string_bool);
+FUNCTION(to_string_unit);

include/trig_functions.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "function_utils.hpp"
+
+FUNCTION(sin);
+FUNCTION(cos);
+FUNCTION(tan);
+
+FUNCTION(arcsin);
+FUNCTION(arccos);
+FUNCTION(arctan);
+