feat add func call and rewrite codes

ccompiler/frontend/frontend.h

@@ -4,8 +4,9 @@
 #ifndef error
 #include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 #define STD_LIBRARY
-#define error(...) do { fprintf(stderr, __VA_ARGS__); exit(1); } while (0)
+#define error(...) do { fprintf(stderr, __VA_ARGS__); assert(0); } while (0)
 #endif
 #ifndef warn
 #include <stdio.h>
@@ -15,10 +16,12 @@
 
 #define xmalloc(size) malloc(size)
 
+#ifndef FRONTEND_IMPLEMENTATION
 #include "parser/parser.h"
 #include "parser/ast/ast.h"
 
 typedef int (*sread_fn)(void *dst_buf, int dst_size, int elem_size, int count, void *stream);
 struct ASTNode* frontend(const char* file, void* stream, sread_fn sread);
+#endif
 
 #endif