Created example with alternative approach to parse args

.vscode/launch.json

@@ -32,7 +32,7 @@
             "name": "(lldb) Launch - Macos",
             "type": "cppdbg",
             "request": "launch",
-            "program": "${fileDirname}/value_ffi_test",
+            "program": "${fileDirname}/c_print_args",
             "args": [],
             "stopAtEntry": false,
             "cwd": "${fileDirname}",

examples/c_ffi_call/value_ffi.c

@@ -121,7 +121,6 @@ static int _val_to_ffi_type(metac_entry_t * p_entry, metac_flag_t variadic, ffi_
             return -ENOMEM;
         }
 #if __linux__
-        va_list x;
         p_ffi_type->type = FFI_TYPE_STRUCT;
         p_ffi_type->size = sizeof(void*);
         p_ffi_type->alignment = p_ffi_type->size;

examples/c_print_args_alt/.gitignore

@@ -0,0 +1 @@
+c_print_args

examples/c_print_args_alt/Makefile

@@ -0,0 +1,39 @@
+ifeq ($(M),)
+METAC_ROOT=../..
+
+all: target test
+
+target:
+	$(MAKE) -C $(METAC_ROOT) M=$(PWD) $(PWD)/c_print_args
+
+clean:
+	$(MAKE) -C $(METAC_ROOT) M=$(PWD) clean
+
+test:
+	$(MAKE) -C $(METAC_ROOT) M=$(PWD) test
+
+.PHONY: all clean
+endif
+
+CFLAGS+=-Wno-varargs -g3
+
+rules+=\
+	c_print_args \
+	_meta_c_print_args \
+	main.reflect.c
+
+TPL-c_print_args:=bin_target
+IN-c_print_args=main.o main.reflect.o
+LDFLAGS-c_print_args=-Lsrc -lmetac
+DEPS-c_print_args=src/libmetac.a
+
+TPL-_meta_c_print_args:=bin_target
+IN-_meta_c_print_args=main.meta.o
+LDFLAGS-_meta_c_print_args=-Lsrc -lmetac
+DEPS-_meta_c_print_args=src/libmetac.a
+POST-_meta_c_print_args=$(METAC_POST_META)
+
+TPL-main.reflect.c:=metac_target
+METACFLAGS-main.reflect.c+=run metac-reflect-gen $(METAC_OVERRIDE_IN_TYPE)
+IN-main.reflect.c=_meta_c_print_args
+

examples/c_print_args_alt/README.md

@@ -0,0 +1,9 @@
+This is an alternative approach to the c_print_args
+
+The original approach requires some non-documented capabilities of va_arg to work with structures and
+va_list (it's not easy to extract struct or va_list from va_list which we used as a storage).
+The current approach in its turn requires `typeof` compiler extension.
+Also this apporach has a limitation of number of arguments: it's necessary to regenerate mr_pp.generated.h using mr_pp.sh and provide the maximum number of arguments. For now it's generated with maximum 1024 arguments
+which is mentioned as a minimum supported number of arguments in C in some referenses.
+And the last limitation is - I wasn't able to find a way to handle arguments with string along with arguments as structs or va_list. When macro unrolls cycle it generates the code which handles each case and I wasn't able
+to find a construction which can be universal. Added TODO there.

examples/c_print_args_alt/main.c

@@ -0,0 +1,84 @@
+
+#include "print_args.h"
+
+#include <stdlib.h> /*free*/
+
+int test_function1_with_args(int a, short b){
+    printf("called\n");
+    return a + b + 6;
+}
+METAC_GSYM_LINK(test_function1_with_args);
+
+typedef struct list_s{
+    double x;
+    struct list_s * p_next;
+}list_t;
+
+double test_function3_with_args(list_t *p_list) {
+    double sum = 0.0;
+    while(p_list != NULL) {
+        sum += p_list->x;
+        p_list->x += 1;
+
+        p_list = p_list->p_next;
+    }
+    printf("!!!result is %f %Lf!!!\n", sum, (long double)sum);
+    return sum;
+}
+METAC_GSYM_LINK(test_function3_with_args);
+
+int my_printf(const char * format, ...) {
+    va_list l;
+    va_start(l, format);
+    int res = vprintf(format, l);
+    va_end(l);
+    return res;
+}
+METAC_GSYM_LINK(my_printf);
+
+enum x {
+    xOne = 1,
+    xTwo = 2,
+    xMinusOne = -1,
+};
+int test_function4_with_enum_args(enum x arg0, enum x arg1, enum x arg2) {
+    return 0;
+}
+METAC_GSYM_LINK(test_function4_with_enum_args);
+
+metac_tag_map_t * p_tagmap = NULL;
+METAC_TAG_MAP_NEW(va_args_tag_map, NULL, {.mask = 
+            METAC_TAG_MAP_ENTRY_CATEGORY_MASK(METAC_TEC_variable) |
+            METAC_TAG_MAP_ENTRY_CATEGORY_MASK(METAC_TEC_func_parameter) | 
+            METAC_TAG_MAP_ENTRY_CATEGORY_MASK(METAC_TEC_member) |
+            METAC_TAG_MAP_ENTRY_CATEGORY_MASK(METAC_TEC_final),},)
+    /* start tags for all types */
+
+    METAC_TAG_MAP_ENTRY(METAC_GSYM_LINK_ENTRY(my_printf))
+        METAC_TAG_MAP_SET_TAG(0, METAC_TEO_entry, 0, METAC_TAG_MAP_ENTRY_PARAMETER({.n = "format"}),
+            METAC_ZERO_ENDED_STRING()
+        )
+        METAC_TAG_MAP_SET_TAG(0, METAC_TEO_entry, 0, METAC_TAG_MAP_ENTRY_PARAMETER({.i = 1}), 
+            METAC_FORMAT_BASED_VA_ARG()
+        )
+    METAC_TAG_MAP_ENTRY_END
+
+METAC_TAG_MAP_END
+//
+
+int main() {
+    p_tagmap = va_args_tag_map();
+
+    printf("fn returned: %i\n", METAC_WRAP_FN_RES(NULL, test_function1_with_args,10, 22));
+
+    list_t * p_list = (list_t[]){{.x = 42.42, .p_next = (list_t[]){{ .x = 45.4, .p_next = NULL}}}};
+    printf("fn returned: %f\n", METAC_WRAP_FN_RES(NULL, test_function3_with_args, p_list));
+
+    printf("fn returned: %i\n", METAC_WRAP_FN_RES(p_tagmap, my_printf, "%d %d\n", 10, 22));
+
+    printf("fn returned: %i\n", METAC_WRAP_FN_RES(p_tagmap, test_function4_with_enum_args, xOne, xTwo, xMinusOne));
+    printf("fn returned: %i\n", METAC_WRAP_FN_RES(p_tagmap, test_function4_with_enum_args, 1, 2, -1));
+
+    metac_tag_map_delete(p_tagmap);
+    return 0;
+}

examples/c_print_args_alt/mr.h

@@ -0,0 +1,27 @@
+// taken from https://github.com/alexanderchuranov/Metaresc/blob/master/src/metaresc.h
+
+#ifndef MR_H_
+#define MR_H_
+
+#include "mr_pp.generated.h"
+
+/* internal macros for arguments evaluation and concatination */
+#define MR_PASTE2(...) MR_PASTE2_ (__VA_ARGS__)
+#define MR_PASTE2_(_0, _1) _0 ## _1
+#define MR_PASTE3(...) MR_PASTE3_ (__VA_ARGS__)
+#define MR_PASTE3_(_0, _1, _2) _0 ## _1 ## _2
+#define MR_PASTE4(...) MR_PASTE4_ (__VA_ARGS__)
+#define MR_PASTE4_(_0, _1, _2, _3) _0 ## _1 ## _2 ## _3
+#define MR_PASTE5(...) MR_PASTE5_ (__VA_ARGS__)
+#define MR_PASTE5_(_0, _1, _2, _3, _4) _0 ## _1 ## _2 ## _3 ## _4
+
+/* Interface macros for unrolled loops from mr_pp.h */
+#define MR_FOREACH(X, ...) MR_PASTE2 (MR_FOREACH, MR_NARG (__VA_ARGS__)) (X, __VA_ARGS__)
+#define MR_FOR(NAME, N, OP, FUNC, ...) MR_PASTE2 (MR_FOR, N) (NAME, OP, FUNC, __VA_ARGS__)
+
+// like car/cdr in lisp
+#define MR_FIRST(_FIRST_, ...) _FIRST_
+#define MR_REST(_FIRST_, ...) __VA_ARGS__
+#define MR_FOREACH_EX(X, ...) MR_PASTE2 (MR_FOREACH_EX_, MR_NARG (__VA_ARGS__)) (X, __VA_ARGS__)
+
+#endif