feat: add prepared error/null ok returns from gen_* functions

src/compiler/generator/gen_class.c

@@ -9,11 +9,11 @@
 gen_res_t gen_class(fzl_gen_t *gen, fzl_node_t *node)
 {
   if (!gen || !node)
-    return (gen_res_t){.error = true};
+    return gen_error;
 
   fzl_gen_ctx_t *ctx = gen_ctx(gen, FZL_GEN_CTX_TYPE_CLASS, node);
   if (!ctx)
-    return (gen_res_t){.error = true};
+    return gen_error;
 
   gen->classes[gen->classes_count] = fzl_mkctable(node->class.name->value);
   fzl_ctable_t *class              = gen->classes[gen->classes_count++];
@@ -37,7 +37,7 @@ gen_res_t gen_class(fzl_gen_t *gen, fzl_node_t *node)
     if (!resolved)
     {
       free(class->fields);
-      return (gen_res_t){.error = true};
+      return gen_error;
     }
 
     class->fields[class->fields_count] = (fzl_ctable_field_t){
@@ -66,7 +66,7 @@ gen_res_t gen_class(fzl_gen_t *gen, fzl_node_t *node)
     if (gen_common(gen, fn).error)
     {
       free(class->fields);
-      return (gen_res_t){.error = true};
+      return gen_error;
     }
   }
 
@@ -74,8 +74,8 @@ gen_res_t gen_class(fzl_gen_t *gen, fzl_node_t *node)
   if (!ctx)
   {
     free(class->fields);
-    return (gen_res_t){.error = true};
+    return gen_error;
   }
 
-  return (gen_res_t){.error = false, .type = FZL_TYPE_NULL, .classname = NULL};
+  return gen_ok_null;
 }