wip: working on extern

- Ref: move extern header into common scope
- Feat: add extern symbols descriptors
- Feat: add `is_out` flag in declaration node

include/common/fzl_extern.h

@@ -0,0 +1,72 @@
+#ifndef FZL_EXTERN_H
+#define FZL_EXTERN_H
+
+#include <common/fzl_types.h>
+#include <stddef.h>
+
+// External library entry types
+typedef enum
+{
+  FZL_EXTERN_KIND_PRIMITIVE,
+  FZL_EXTERN_KIND_HANDLE,
+  FZL_EXTERN_KIND_STRUCT,
+  FZL_EXTERN_KIND_REF,
+  FZL_EXTERN_KIND_ALIAS,
+} fzl_extern_kind_t;
+
+// External library structure field descriptor
+typedef struct
+{
+  char *name;
+  fzl_type_t type;
+} fzl_extern_struct_field_t;
+
+// Extern symbol type descriptor
+typedef struct fzl_extern_type
+{
+  size_t lib_slot;
+  fzl_extern_kind_t kind;
+  char *symbol_name;
+  char *used_name;
+
+  union
+  {
+    // Structure data
+    struct
+    {
+      fzl_extern_struct_field_t **fields;
+      size_t fields_count;
+    } structure;
+
+    // Reference
+    struct fzl_extern_type *ref_of;
+
+    // Aliasing type
+    fzl_type_t alias;
+
+    // Primitive type
+    // NOTE: same type as `.alias` just for readable format
+    fzl_type_t primitive;
+  };
+} fzl_extern_type_t;
+
+// Extern symbol function descriptor
+typedef struct
+{
+  size_t lib_slot;
+  char *symbol_name;
+  char *used_name;
+
+  fzl_extern_type_t *ret_type;
+
+  fzl_extern_type_t **args;
+  size_t args_count;
+} fzl_extern_fn_t;
+
+// External library descriptor
+typedef struct
+{
+  char *name;
+} fzl_extern_lib_t;
+
+#endif // FZL_EXTERN_H

include/compiler/fzl_parser.h

@@ -3,6 +3,7 @@
 
 #include <compiler/fzl_reader.h>
 #include <compiler/fzl_token.h>
+#include <stdbool.h>
 #include <stddef.h>
 
 // AST node type
@@ -106,6 +107,7 @@ typedef struct fzl_node
     {
       fzl_token_t *type;
       struct fzl_node *identifier;
+      bool is_out;
     } var;
 
     // Conditional blocks

include/compiler/utils/fzl_extern.h

@@ -1,16 +0,0 @@
-#ifndef FZL_EXTERN_H
-#define FZL_EXTERN_H
-
-// Library symbol descriptor
-typedef struct
-{
-  //
-} fzl_extern_item_t;
-
-// External library descriptor
-typedef struct
-{
-  //
-} fzl_extern_lib_t;
-
-#endif // FZL_EXTERN_H