Binding WalkTo(SymbolExpression expression, out string[] missingTokens)
{
ValidateThatRecursionIsNotOccuring(expression);
symbolStack.Push(expression);
try
{
var val = binding;
missingTokens = new string[0];
expression = CopyExpression(expression);
foreach (var step in expression.Steps)
{
var iss = step as Identifier;
if (iss != null)
{
Binding newVal;
if (val.TryGetValue(iss.Text, out newVal))
{
val = newVal;
continue;
}
if (TryCustomParsers(val, iss.Text, out newVal))
{
val = newVal;
continue;
}
}
else
{
var ix = step as Indexer;
if (ix != null)
{
if (ix.IsSymbol)
{
// Substitution should have taken place in previous CopyExpression above.
// If not then it must not be found.
return(null);
}
if (ix.Index == "*" && val.Indexable.Count > 0)
{
val = val.Indexable.First().Value;
continue;
}
Binding newVal;
if (val.Indexable.TryGetValue(ix.Index, out newVal))
{
val = newVal;
continue;
}
if (TryCustomParsers(val, ix.Index, out newVal))
{
val = newVal;
continue;
}
}
else
{
throw new NotImplementedException("Unknown step type: " + step);
}
}
if (parent == null)
{
return(null);
}
return(parent.WalkTo(expression, out missingTokens));
}
return(ParseTemplate(val, out missingTokens));
}
finally
{
symbolStack.Pop();
}
}
Binding WalkTo(SymbolExpression expression, out string[] missingTokens)
{
ValidateNoRecursion(expression);
symbolStack.Push(expression);
try
{
var val = binding;
missingTokens = new string[0];
//any indexers that are lookups, do them now so we are in the right context
//take a copy so the lookup version remains for later use
expression = new SymbolExpression(expression.Steps.Select(s =>
{
var indexer = s as Indexer;
if (indexer != null && indexer.IsSymbol)
{
string[] missing;
var index = WalkTo(indexer.Symbol, out missing);
return(new Indexer(index.Item));
}
return(s);
}));
foreach (var step in expression.Steps)
{
var iss = step as Identifier;
if (iss != null)
{
if (val.TryGetValue(iss.Text, out val))
{
continue;
}
}
else
{
var ix = step as Indexer;
if (ix != null && !ix.IsSymbol)
{
if (ix.Index == "*" && val.Indexable.Count > 0)
{
val = val.Indexable.First().Value;
continue;
}
if (val.Indexable.TryGetValue(ix.Index, out val))
{
continue;
}
}
else
{
throw new NotImplementedException("Unknown step type: " + step);
}
}
if (parent == null)
{
return(null);
}
return(parent.WalkTo(expression, out missingTokens));
}
if (val != null && val.Item != null)
{
Template template;
string error;
if (TemplateParser.TryParseTemplate(val.Item, out template, out error))
{
using (var x = new StringWriter())
{
var context = new EvaluationContext(new Binding(), x, this);
TemplateEvaluator.Evaluate(template, context, out missingTokens);
x.Flush();
return(new Binding(x.ToString()));
}
}
}
return(val);
}
finally
{
symbolStack.Pop();
}
}