public BoundExpression BindExpression(ExpressionSyntax node)
{
switch (node.Kind)
{
case SyntaxKind.TrueLiteralExpression:
case SyntaxKind.FalseLiteralExpression:
case SyntaxKind.NumericLiteralExpression:
case SyntaxKind.StringLiteralExpression:
return ProcessLiteral((LiteralExpressionSyntax) node);
case SyntaxKind.IdentifierName:
return ProcessIdentifierName((IdentifierNameSyntax) node);
case SyntaxKind.PreDecrementExpression:
case SyntaxKind.PreIncrementExpression:
return ProcessPrefixUnary((PrefixUnaryExpressionSyntax) node);
case SyntaxKind.UnaryMinusExpression:
case SyntaxKind.UnaryPlusExpression:
case SyntaxKind.LogicalNotExpression:
case SyntaxKind.BitwiseNotExpression:
case SyntaxKind.PostDecrementExpression:
case SyntaxKind.PostIncrementExpression:
return ProcessPostfixUnary((PostfixUnaryExpressionSyntax)node);
case SyntaxKind.MemberAccessExpression:
return ProcessMemberAccess((MemberAccessExpressionSyntax) node);
default:
throw new ArgumentOutOfRangeException();
}
}
private object Evaluate(ExpressionSyntax expr)
{
if (expr == null)
return null;
switch (expr.Kind)
{
case SyntaxKind.ParenthesizedExpression:
return Evaluate(((ParenthesizedExpressionSyntax)expr).Expression);
case SyntaxKind.TrueLiteralExpression:
case SyntaxKind.FalseLiteralExpression:
case SyntaxKind.NumericLiteralExpression:
return ((LiteralExpressionSyntax)expr).Token.Value;
case SyntaxKind.LogicalAndExpression:
case SyntaxKind.BitwiseAndExpression:
return EvaluateBool(((BinaryExpressionSyntax)expr).Left) && EvaluateBool(((BinaryExpressionSyntax)expr).Right);
case SyntaxKind.LogicalOrExpression:
case SyntaxKind.BitwiseOrExpression:
return EvaluateBool(((BinaryExpressionSyntax)expr).Left) || EvaluateBool(((BinaryExpressionSyntax)expr).Right);
case SyntaxKind.EqualsExpression:
return Equals(Evaluate(((BinaryExpressionSyntax)expr).Left), Evaluate(((BinaryExpressionSyntax)expr).Right));
case SyntaxKind.NotEqualsExpression:
return !Equals(Evaluate(((BinaryExpressionSyntax)expr).Left), Evaluate(((BinaryExpressionSyntax)expr).Right));
case SyntaxKind.LogicalNotExpression:
return !EvaluateBool(((PrefixUnaryExpressionSyntax)expr).Operand);
case SyntaxKind.AddExpression:
return EvaluateInt(((BinaryExpressionSyntax)expr).Left) + EvaluateInt(((BinaryExpressionSyntax)expr).Right);
case SyntaxKind.SubtractExpression:
return EvaluateInt(((BinaryExpressionSyntax)expr).Left) - EvaluateInt(((BinaryExpressionSyntax)expr).Right);
case SyntaxKind.MultiplyExpression:
return EvaluateInt(((BinaryExpressionSyntax)expr).Left) * EvaluateInt(((BinaryExpressionSyntax)expr).Right);
case SyntaxKind.DivideExpression:
var divisor = EvaluateInt(((BinaryExpressionSyntax) expr).Right);
return (divisor != 0)
? EvaluateInt(((BinaryExpressionSyntax) expr).Left) / divisor
: int.MaxValue;
case SyntaxKind.IdentifierName:
var id = ((IdentifierNameSyntax)expr).Name.Text;
return IsDirectiveDefined(id);
case SyntaxKind.InvocationExpression:
// It must be a call to "defined" - that's the only one allowed by the parser.
var functionCall = (InvocationExpressionSyntax)expr;
var identifierName = ((IdentifierNameSyntax)functionCall.ArgumentList.Arguments[0]).Name;
return IsDirectiveDefined(identifierName.Text);
default:
return false;
}
}
private int EvaluateInt(ExpressionSyntax expr)
{
var result = Evaluate(expr);
if (result is int)
return (int)result;
return 0;
}
private bool EvaluateBool(ExpressionSyntax expr)
{
var result = Evaluate(expr);
if (result is bool)
return (bool)result;
if (result is int)
return (int)result != 0;
return false;
}
private ExpressionSyntax ParsePostFixExpression(ExpressionSyntax expr)
{
Debug.Assert(expr != null);
while (true)
{
var tk = Current.Kind;
switch (tk)
{
case SyntaxKind.OpenParenToken:
expr = new InvocationExpressionSyntax(expr, ParseParenthesizedArgumentList(false));
break;
case SyntaxKind.OpenBracketToken:
expr = new ElementAccessExpressionSyntax(expr,
Match(SyntaxKind.OpenBracketToken),
ParseExpression(),
Match(SyntaxKind.CloseBracketToken));
break;
case SyntaxKind.PlusPlusToken:
case SyntaxKind.MinusMinusToken:
expr = new PostfixUnaryExpressionSyntax(SyntaxFacts.GetPostfixUnaryExpression(tk), expr, NextToken());
break;
case SyntaxKind.DotToken:
expr = new MemberAccessExpressionSyntax(expr, NextToken(), ParseIdentifier());
break;
default:
return expr;
}
}
}
private BoundExpression GetBoundExpression(ExpressionSyntax expression)
{
return _bindingResult.GetBoundNode(expression) as BoundExpression;
}
public Symbol GetSymbol(ExpressionSyntax expression)
{
var boundExpression = GetBoundExpression(expression);
return boundExpression == null ? null : GetSymbol(boundExpression);
}
public TypeSymbol GetExpressionType(ExpressionSyntax expression)
{
var boundExpression = GetBoundExpression(expression);
return boundExpression?.Type;
}