From b572f4ef7c45f61dff0ccc141bea6e678ba2856c Mon Sep 17 00:00:00 2001
From: Krzosa Karol <krzosa.karol@gmail.com>
Date: Wed, 29 Mar 2023 09:34:33 +0200
Subject: [PATCH] Parsing union

---
 core_ast.cpp              |  4 +++-
 core_parsing.cpp          | 11 +++++++----
 examples/push_struct.core |  4 ++++
 meta.py                   |  9 ++++-----
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/core_ast.cpp b/core_ast.cpp
index 259239e..0369402 100644
--- a/core_ast.cpp
+++ b/core_ast.cpp
@@ -214,8 +214,10 @@ finalize_stmt_scope(Ast_Scope *scope) {
 }
 
 CORE_Static Ast_Decl *
-ast_struct(Token *pos, Ast_Scope *scope) {
+ast_struct(Token *pos, Ast_Scope *scope, Ast_Kind kind = AST_STRUCT) {
+    assert(kind == AST_STRUCT || kind == AST_UNION);
     AST_NEW(Decl, STRUCT, pos, AST_DECL | AST_AGGREGATE);
+    result->kind = kind;
     result->scope = scope;
     return result;
 }
diff --git a/core_parsing.cpp b/core_parsing.cpp
index 8dbaffb..2ed93ca 100644
--- a/core_parsing.cpp
+++ b/core_parsing.cpp
@@ -692,7 +692,7 @@ parse_assign_expr() {
 }
 
 CORE_Static Ast_Decl *
-parse_struct(Token *pos) {
+parse_struct(Token *pos, Ast_Kind kind) {
     Scratch_Scope scratch(pctx->scratch);
 
     token_match(OPEN_SCOPE);
@@ -711,7 +711,7 @@ parse_struct(Token *pos) {
     token_expect(CLOSE_SCOPE);
 
     finalize_decl_scope(scope);
-    Ast_Decl *result = ast_struct(pos, scope);
+    Ast_Decl *result = ast_struct(pos, scope, kind);
     return result;
 }
 
@@ -853,9 +853,12 @@ parse_decl(B32 is_global) {
             set_flag(flags, AST_STRICT);
         }
 
-        // @note parse struct binding
         if (token_match_keyword(pctx->keyword_struct)) {
-            result = parse_struct(tname);
+            result = parse_struct(tname, AST_STRUCT);
+        }
+
+        else if (token_match_keyword(pctx->keyword_union)) {
+            result = parse_struct(tname, AST_UNION);
         }
 
         else if (token_match_keyword(pctx->keyword_enum)) {
diff --git a/examples/push_struct.core b/examples/push_struct.core
index 94daf95..7ae2ff4 100644
--- a/examples/push_struct.core
+++ b/examples/push_struct.core
@@ -12,6 +12,10 @@ PushStruct :: (a: *MA.Arena, type: Type): *void
 	result := MA.PushSize(a, ti.size->U64)
 	return result
 
+U :: union
+	a: F64
+	b: F32
+
 main :: (argc: int, argv: **char): int
 	arena: MA.Arena
 	a: *int = PushStruct(&arena, int)
diff --git a/meta.py b/meta.py
index 075b5f9..6789cf1 100644
--- a/meta.py
+++ b/meta.py
@@ -135,11 +135,11 @@ value_struct_content = """
 Ast_Type *type;
 Ast_Decl *resolved_decl;
 union {
-    bool          bool_val;   
-    double        f64_val;    
-    Intern_String intern_val; 
+    bool          bool_val;
+    double        f64_val;
+    Intern_String intern_val;
     BigInt        big_int_val;
-    Ast_Type     *type_val;            
+    Ast_Type     *type_val;
 };
 """.strip()
 
@@ -152,4 +152,3 @@ union {{
     }};
 }};
     """.strip())
-    
\ No newline at end of file