From 0c09cceffc3861a5f1d8bde0a075828d61bd6c78 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Tue, 26 Oct 2010 02:05:21 -0400
Subject: [PATCH] Made struct dereference a separate expression type, not a
 binary expression.

---
 mojoshader_compiler.c        | 26 +++++++++++++++++++++++---
 mojoshader_parser_hlsl.lemon |  2 +-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/mojoshader_compiler.c b/mojoshader_compiler.c
index 4e992f00..54de5bff 100644
--- a/mojoshader_compiler.c
+++ b/mojoshader_compiler.c
@@ -59,7 +59,6 @@ typedef enum ASTNodeType
 
     AST_OP_START_RANGE_BINARY,
     AST_OP_DEREF_ARRAY,
-    AST_OP_DEREF_STRUCT,
     AST_OP_COMMA,
     AST_OP_MULTIPLY,
     AST_OP_DIVIDE,
@@ -105,6 +104,7 @@ typedef enum ASTNodeType
     AST_OP_END_RANGE_DATA,
 
     AST_OP_START_RANGE_MISC,
+    AST_OP_DEREF_STRUCT,
     AST_OP_CALLFUNC,
     AST_OP_CONSTRUCTOR,
     AST_OP_CAST,
@@ -281,6 +281,13 @@ typedef struct ExpressionConstructor
     Arguments *args;
 } ExpressionConstructor;
 
+typedef struct ExpressionDerefStruct
+{
+    ASTNode ast;  // Always AST_OP_DEREF_STRUCT
+    Expression *identifier;
+    const char *member;
+} ExpressionDerefStruct;
+
 typedef struct ExpressionCallFunction
 {
     ASTNode ast;  // Always AST_OP_CALLFUNC
@@ -809,6 +816,15 @@ static Expression *new_ternary_expr(Context *ctx, const ASTNodeType op,
     return (Expression *) retval;
 } // new_ternary_expr
 
+static Expression *new_deref_struct_expr(Context *ctx, Expression *identifier,
+                                         const char *member)
+{
+    NEW_AST_NODE(retval, ExpressionDerefStruct, AST_OP_DEREF_STRUCT);
+    retval->identifier = identifier;
+    retval->member = member;  // cached; don't copy string.
+    return (Expression *) retval;
+} // new_deref_struct_expr
+
 static Expression *new_identifier_expr(Context *ctx, const char *string)
 {
     NEW_AST_NODE(retval, ExpressionIdentifier, AST_OP_IDENTIFIER);
@@ -875,6 +891,10 @@ static void delete_expr(Context *ctx, Expression *expr)
     {
         delete_arguments(ctx, ((ExpressionConstructor *) expr)->args);
     } // else if
+    else if (expr->ast.type == AST_OP_DEREF_STRUCT)
+    {
+        delete_expr(ctx, ((ExpressionDerefStruct *) expr)->identifier);
+    } // else if
     else if (expr->ast.type == AST_OP_CALLFUNC)
     {
         delete_expr(ctx, ((ExpressionCallFunction *) expr)->identifier);
@@ -1601,9 +1621,9 @@ static void print_ast(const int substmt, void *ast)
             break;
 
         case AST_OP_DEREF_STRUCT:
-            print_ast(0, ((ExpressionBinary *) ast)->left);
+            print_ast(0, ((ExpressionDerefStruct *) ast)->identifier);
             printf(".");
-            print_ast(0, ((ExpressionBinary *) ast)->right);
+            printf("%s", ((ExpressionDerefStruct *) ast)->member);
             break;
 
         case AST_OP_COMMA:
diff --git a/mojoshader_parser_hlsl.lemon b/mojoshader_parser_hlsl.lemon
index 93a7adb0..ff66e0b7 100644
--- a/mojoshader_parser_hlsl.lemon
+++ b/mojoshader_parser_hlsl.lemon
@@ -470,7 +470,7 @@ postfix_expr(A) ::= primary_expr(B). { A = B; }
 postfix_expr(A) ::= postfix_expr(B) LBRACKET expression(C) RBRACKET. { A = new_binary_expr(ctx, AST_OP_DEREF_ARRAY, B, C); }
 postfix_expr(A) ::= postfix_expr(B) arguments(C). { A = new_callfunc_expr(ctx, B, C); }
 postfix_expr(A) ::= datatype(B) arguments(C). { A = new_constructor_expr(ctx, B, C); } // HLSL constructor
-postfix_expr(A) ::= postfix_expr(B) DOT IDENTIFIER(C). { A = new_binary_expr(ctx, AST_OP_DEREF_STRUCT, B, new_identifier_expr(ctx, C.string)); }
+postfix_expr(A) ::= postfix_expr(B) DOT IDENTIFIER(C). { A = new_deref_struct_expr(ctx, B, C.string); }
 postfix_expr(A) ::= postfix_expr(B) PLUSPLUS. { A = new_unary_expr(ctx, AST_OP_POSTINCREMENT, B); }
 postfix_expr(A) ::= postfix_expr(B) MINUSMINUS. { A = new_unary_expr(ctx, AST_OP_POSTDECREMENT, B); }