public override ValueReference Evaluate(EvaluationContext ctx, string expression, object expectedType)
{
expression = expression.Trim();
if (expression.Length > 0 && expression[0] == '?')
{
expression = expression.Substring(1).TrimStart();
}
if (expression.Length > 3 && expression.StartsWith("var", StringComparison.Ordinal) && char.IsWhiteSpace(expression[3]))
{
expression = expression.Substring(4).TrimStart();
string variable = null;
for (int n = 0; n < expression.Length; n++)
{
if (!char.IsLetterOrDigit(expression[n]) && expression[n] != '_')
{
variable = expression.Substring(0, n);
if (!expression.Substring(n).TrimStart().StartsWith("=", StringComparison.Ordinal))
{
variable = null;
}
break;
}
if (n == expression.Length - 1)
{
variable = expression;
expression = null;
break;
}
}
if (!string.IsNullOrEmpty(variable))
{
userVariables[variable] = new UserVariableReference(ctx, variable);
}
if (expression == null)
{
return(null);
}
}
expression = ReplaceExceptionTag(expression, ctx.Options.CurrentExceptionTag);
var expr = new CSharpParser().ParseExpression(expression);
if (expr == null)
{
throw new EvaluatorException("Could not parse expression '{0}'", expression);
}
var evaluator = new NRefactoryExpressionEvaluatorVisitor(ctx, expression, expectedType, userVariables);
return(expr.AcceptVisitor(evaluator));
}
ValueReference Evaluate (EvaluationContext ctx, string exp, object expectedType, bool tryTypeOf)
{
exp = exp.TrimStart ();
if (exp.StartsWith ("?"))
exp = exp.Substring (1).Trim ();
if (exp.StartsWith ("var ")) {
exp = exp.Substring (4).Trim (' ','\t');
string var = null;
for (int n=0; n<exp.Length; n++) {
if (!char.IsLetterOrDigit (exp[n]) && exp[n] != '_') {
var = exp.Substring (0, n);
if (!exp.Substring (n).Trim (' ','\t').StartsWith ("="))
var = null;
break;
}
if (n == exp.Length - 1) {
var = exp;
exp = null;
break;
}
}
if (!string.IsNullOrEmpty (var))
userVariables [var] = new UserVariableReference (ctx, var);
if (exp == null)
return null;
}
exp = ReplaceExceptionTag (exp, ctx.Options.CurrentExceptionTag);
StringReader codeStream = new StringReader (exp);
IParser parser = ParserFactory.CreateParser (SupportedLanguage.CSharp, codeStream);
Expression expObj = parser.ParseExpression ();
if (expObj == null)
throw new EvaluatorException ("Could not parse expression '{0}'", exp);
try {
EvaluatorVisitor ev = new EvaluatorVisitor (ctx, exp, expectedType, userVariables, tryTypeOf);
return (ValueReference) expObj.AcceptVisitor (ev, null);
} catch {
if (!tryTypeOf && (expObj is BinaryOperatorExpression) && IsTypeName (exp)) {
// This is a hack to be able to parse expressions such as "List<string>". The NRefactory parser
// can parse a single type name, so a solution is to wrap it around a typeof(). We do it if
// the evaluation fails.
return Evaluate (ctx, "typeof(" + exp + ")", expectedType, true);
} else
throw;
}
}
public override ValueReference Evaluate (EvaluationContext ctx, string expression, object expectedType)
{
expression = expression.TrimStart ();
if (expression.Length > 0 && expression[0] == '?')
expression = expression.Substring (1).Trim ();
if (expression.StartsWith ("var", StringComparison.Ordinal) && char.IsWhiteSpace (expression[3])) {
expression = expression.Substring (4).Trim (' ', '\t');
string variable = null;
for (int n = 0; n < expression.Length; n++) {
if (!char.IsLetterOrDigit (expression[n]) && expression[n] != '_') {
variable = expression.Substring (0, n);
if (!expression.Substring (n).Trim (' ', '\t').StartsWith ("=", StringComparison.Ordinal))
variable = null;
break;
}
if (n == expression.Length - 1) {
variable = expression;
expression = null;
break;
}
}
if (!string.IsNullOrEmpty (variable))
userVariables[variable] = new UserVariableReference (ctx, variable);
if (expression == null)
return null;
}
expression = ReplaceExceptionTag (expression, ctx.Options.CurrentExceptionTag);
var expr = new CSharpParser ().ParseExpression (expression);
if (expr == null)
throw new EvaluatorException ("Could not parse expression '{0}'", expression);
var evaluator = new NRefactoryExpressionEvaluatorVisitor (ctx, expression, expectedType, userVariables);
return expr.AcceptVisitor<ValueReference> (evaluator);
}