private static int?GetMultiplier(ExpressionSyntax expression, out ExpressionSyntax internalExpression)
{
var multiplier = 1;
internalExpression = expression;
var unary = internalExpression as PrefixUnaryExpressionSyntax;
while (unary != null)
{
var op = unary.OperatorToken;
if (!SupportedOperatorTokens.Contains(op.Kind()))
{
return(null);
}
if (op.IsKind(SyntaxKind.MinusToken))
{
multiplier *= -1;
}
internalExpression = unary.Operand;
unary = internalExpression as PrefixUnaryExpressionSyntax;
}
return(multiplier);
}
internal static bool TryGetConstantIntValue(ExpressionSyntax expression, out int value)
{
var multiplier = 1;
var expr = expression;
var unary = expr as PrefixUnaryExpressionSyntax;
while (unary != null)
{
var op = unary.OperatorToken;
if (!SupportedOperatorTokens.Contains(op.Kind()))
{
value = 0;
return(false);
}
if (op.IsKind(SyntaxKind.MinusToken))
{
multiplier *= -1;
}
expr = unary.Operand;
unary = expr as PrefixUnaryExpressionSyntax;
}
var literalExpression = expr as LiteralExpressionSyntax;
if (literalExpression != null &&
TryConvert(literalExpression.Token.Value, out value))
{
value = multiplier * value;
return(true);
}
value = 0;
return(false);
}