1.1 --- a/src/compiler/ConstantEvaluator.cpp	Sat Nov 17 23:13:39 2012 -0800
     1.2 +++ b/src/compiler/ConstantEvaluator.cpp	Sun Nov 18 14:53:23 2012 -0800
     1.3 @@ -0,0 +1,92 @@
     1.4 +/* vim: set ts=4 sw=4 tw=99 et:
     1.5 + *
     1.6 + * Copyright (C) 2012 David Anderson
     1.7 + *
     1.8 + * This file is part of SourcePawn.
     1.9 + *
    1.10 + * SourcePawn is free software: you can redistribute it and/or modify it under
    1.11 + * the terms of the GNU General Public License as published by the Free
    1.12 + * Software Foundation, either version 3 of the License, or (at your option)
    1.13 + * any later version.
    1.14 + * 
    1.15 + * SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY
    1.16 + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    1.17 + * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
    1.18 + *
    1.19 + * You should have received a copy of the GNU General Public License along with
    1.20 + * SourcePawn. If not, see http://www.gnu.org/licenses/.
    1.21 + */
    1.22 +#include "AST.h"
    1.23 +#include "ConstantEvaluator.h"
    1.24 +
    1.25 +using namespace ke;
    1.26 +
    1.27 +static inline bool
    1.28 +EvaluateBinaryOperation(TokenKind kind, const BoxedPrimitive &left, const BoxedPrimitive &right,
    1.29 +                        BoxedPrimitive *out)
    1.30 +{
    1.31 +    switch (kind) {
    1.32 +      case TOK_PLUS:
    1.33 +        *out = BoxedPrimitive::Int(left.toInt() + right.toInt());
    1.34 +        return true;
    1.35 +
    1.36 +      case TOK_SHL:
    1.37 +        *out = BoxedPrimitive::Int(left.toInt() << right.toInt());
    1.38 +        return true;
    1.39 +
    1.40 +      default:
    1.41 +        return false;
    1.42 +    }
    1.43 +}
    1.44 +
    1.45 +static inline bool
    1.46 +EvaluateUnaryOperation(TokenKind kind, const BoxedPrimitive &inner, BoxedPrimitive *out)
    1.47 +{
    1.48 +  switch (kind) {
    1.49 +    case TOK_MINUS:
    1.50 +      *out = BoxedPrimitive::Int(-inner.toInt());
    1.51 +      return true;
    1.52 +
    1.53 +    default:
    1.54 +      return false;
    1.55 +  }
    1.56 +}
    1.57 +
    1.58 +bool
    1.59 +ke::EvaluateForConstant(Expression *expr, BoxedPrimitive *out)
    1.60 +{
    1.61 +    switch (expr->kind()) {
    1.62 +      case AstNode::kBinaryExpression:
    1.63 +      {
    1.64 +        BoxedPrimitive left;
    1.65 +        BoxedPrimitive right;
    1.66 +        BinaryExpression *b = expr->toBinaryExpression();
    1.67 +        if (!EvaluateForConstant(b->left(), &left) ||
    1.68 +            !EvaluateForConstant(b->right(), &right))
    1.69 +        {
    1.70 +            return false;
    1.71 +        }
    1.72 +        return EvaluateBinaryOperation(b->token(), left, right, out);
    1.73 +      }
    1.74 +
    1.75 +      case AstNode::kUnaryExpression:
    1.76 +      {
    1.77 +        BoxedPrimitive inner;
    1.78 +        UnaryExpression *u = expr->toUnaryExpression();
    1.79 +        if (!EvaluateForConstant(u->expression(), &inner))
    1.80 +            return false;
    1.81 +        return EvaluateUnaryOperation(u->token(), inner, out);
    1.82 +      }
    1.83 +
    1.84 +      case AstNode::kBooleanLiteral:
    1.85 +        *out = BoxedPrimitive::Int(expr->toBooleanLiteral()->token() == TOK_TRUE ? 1 : 0);
    1.86 +        return true;
    1.87 +
    1.88 +      case AstNode::kIntegerLiteral:
    1.89 +        *out = BoxedPrimitive::Int(expr->toIntegerLiteral()->value());
    1.90 +        return true;
    1.91 +
    1.92 +      default:
    1.93 +        return false;
    1.94 +    }
    1.95 +}