From b4957586e4930dafdd8d7efe5290c34751fd9a57 Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Sat, 26 Dec 2020 00:00:00 +0000
Subject: [PATCH] Adds constant feature.

---
 TODO.TXT |  2 +-
 biner.l  |  1 +
 biner.y  | 21 +++++++++++++++------
 main.c   |  3 +++
 tree.h   |  6 ++++--
 5 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/TODO.TXT b/TODO.TXT
index dfb0ada..ba18068 100644
--- a/TODO.TXT
+++ b/TODO.TXT
@@ -5,7 +5,7 @@ X make enum for generic types
 X constant resolving in expression
 X check if an expression is static/dynamic
 X enum support
-  constant support
+X constant support
   conditional switching support
   union support
   transpiler for C
diff --git a/biner.l b/biner.l
index b60e6b3..49d7067 100644
--- a/biner.l
+++ b/biner.l
@@ -24,6 +24,7 @@ H [0-9A-Fa-f]
 "//".* count_();
 [/][*][^*]*[*]+([^*/][^*]*[*]+)*[/] count_(); /* TODO: detect unterminated comment */
 
+"const"  { count_(); return CONST; }
 "enum"   { count_(); return ENUM; }
 "struct" { count_(); return STRUCT; }
 
diff --git a/biner.y b/biner.y
index 84a43b7..e498d55 100644
--- a/biner.y
+++ b/biner.y
@@ -83,7 +83,7 @@ resolve_constant_(
   uintptr_t ptr;
 }
 
-%token ENUM STRUCT
+%token CONST ENUM STRUCT
 %token <ptr> IDENT
 %token <i>   INTEGER;
 
@@ -98,13 +98,13 @@ resolve_constant_(
 %%
 
 decl_list
-  : decl {
+  : decl ';' {
     *ref(biner_tree_root_t, ctx.root) = (biner_tree_root_t) {
       .decls = $1,
     };
     $$ = ctx.root;
   }
-  | decl_list decl {
+  | decl_list decl ';' {
     ref(biner_tree_decl_t, $2)->prev  = ref(biner_tree_root_t, $1)->decls;
     ref(biner_tree_root_t, $1)->decls = $2;
     $$ = $1;
@@ -112,15 +112,19 @@ decl_list
   ;
 
 decl
-  : ENUM IDENT '{' enum_member_list '}' ';' {
+  : CONST IDENT '=' expr {
+    $$ = create_decl_($2, BINER_TREE_DECL_TYPE_CONST, $4);
+    if ($$ == 0) YYABORT;
+  }
+  | ENUM IDENT '{' enum_member_list '}' {
     $$ = create_decl_($2, BINER_TREE_DECL_TYPE_ENUM, $4);
     if ($$ == 0) YYABORT;
   }
-  | ENUM IDENT '{' enum_member_list ',' '}' ';' {
+  | ENUM IDENT '{' enum_member_list ',' '}' {
     $$ = create_decl_($2, BINER_TREE_DECL_TYPE_ENUM, $4);
     if ($$ == 0) YYABORT;
   }
-  | STRUCT IDENT '{' struct_member_list '}' ';' {
+  | STRUCT IDENT '{' struct_member_list '}' {
     $$ = create_decl_($2, BINER_TREE_DECL_TYPE_STRUCT, $4);
     if ($$ == 0) YYABORT;
   }
@@ -436,6 +440,11 @@ static inline biner_zone_ptr(biner_tree_expr_t) resolve_constant_(
   while (itr) {
     const biner_tree_decl_t* decl = ref(biner_tree_decl_t, itr);
     switch (decl->type) {
+    case BINER_TREE_DECL_TYPE_CONST:
+      if (strcmp(ref(char, decl->name), ref(char, ident)) == 0) {
+        expr = decl->const_;
+      }
+      break;
     case BINER_TREE_DECL_TYPE_ENUM:
       expr = find_enum_member_by_name_(decl->enum_, ident);
       break;
diff --git a/main.c b/main.c
index 8094573..5783388 100644
--- a/main.c
+++ b/main.c
@@ -54,6 +54,9 @@ int main(void) {
     (const biner_tree_decl_t*) (zone + root->decls);
   while ((uintptr_t) decl != (uintptr_t) zone) {
     switch (decl->type) {
+    case BINER_TREE_DECL_TYPE_CONST:
+      printf("const %s\n", zone + decl->name);
+      break;
     case BINER_TREE_DECL_TYPE_ENUM:
       print_enum_(zone, decl);
       break;
diff --git a/tree.h b/tree.h
index 092b1d7..1cc290e 100644
--- a/tree.h
+++ b/tree.h
@@ -96,8 +96,9 @@ typedef struct biner_tree_enum_member_t {
 } biner_tree_enum_member_t;
 
 typedef enum biner_tree_decl_type_t {
-  BINER_TREE_DECL_TYPE_STRUCT,
+  BINER_TREE_DECL_TYPE_CONST,
   BINER_TREE_DECL_TYPE_ENUM,
+  BINER_TREE_DECL_TYPE_STRUCT,
 } biner_tree_decl_type_t;
 
 typedef struct biner_tree_decl_t {
@@ -106,8 +107,9 @@ typedef struct biner_tree_decl_t {
   union {
     biner_zone_ptr(void) body;
 
-    biner_zone_ptr(biner_tree_struct_member_t) struct_;
+    biner_zone_ptr(biner_tree_expr_t)          const_;
     biner_zone_ptr(biner_tree_enum_member_t)   enum_;
+    biner_zone_ptr(biner_tree_struct_member_t) struct_;
   };
   biner_zone_ptr(biner_tree_decl_t) prev;
 } biner_tree_decl_t;