private List <DocumentToken> ReadReplacementBody(TokenReader <DocumentToken> reader, DocumentToken replacementKeyToken)
{
List <DocumentToken> replacementContents = new List <DocumentToken>();
int numOpenReplacements = 1;
while (reader.CanAdvance())
{
if (reader.Peek().TokenType == DocumentTokenType.BeginReplacementSegment)
{
numOpenReplacements++;
}
else if (reader.Peek().TokenType == DocumentTokenType.QuickTerminateReplacementSegment)
{
numOpenReplacements--;
if (numOpenReplacements == 0)
{
throw Unexpected(reader.Peek());
}
}
else if (reader.Peek().TokenType == DocumentTokenType.BeginTerminateReplacementSegment)
{
numOpenReplacements--;
if (numOpenReplacements == 0)
{
AdvanceAndExpectConstantType(reader, DocumentTokenType.BeginTerminateReplacementSegment);
AdvanceAndExpect(reader, DocumentTokenType.ReplacementKey, replacementKeyToken.Value, skipWhitespace: true);
AdvanceAndExpectConstantType(reader, DocumentTokenType.EndReplacementSegment);
break;
}
}
replacementContents.Add(reader.Advance());
}
if (numOpenReplacements != 0)
{
throw Unexpected("end of '" + replacementKeyToken.Value + "' replacement");
}
return(replacementContents);
}
private void ParseReplacement(TokenReader <DocumentToken> reader, List <IDocumentExpression> ret)
{
var openToken = AdvanceAndExpectConstantType(reader, DocumentTokenType.BeginReplacementSegment);
var replacementKeyToken = AdvanceAndExpect(reader, DocumentTokenType.ReplacementKey, "replacement key", skipWhitespace: true);
List <DocumentToken> parameters = new List <DocumentToken>();
List <DocumentToken> body = new List <DocumentToken>();
while (reader.CanAdvance(skipWhitespace: true) && reader.Peek(skipWhitespace: true).TokenType == DocumentTokenType.ReplacementParameter)
{
var paramToken = reader.Advance(skipWhitespace: true);
parameters.Add(paramToken);
}
DocumentToken closeReplacementToken;
if (reader.TryAdvance(out closeReplacementToken, skipWhitespace: true) == false)
{
throw Unexpected(string.Format("'{0}' or '{1}'", DocumentToken.GetTokenTypeValue(DocumentTokenType.EndReplacementSegment), DocumentToken.GetTokenTypeValue(DocumentTokenType.QuickTerminateReplacementSegment)));
}
if (closeReplacementToken.TokenType == DocumentTokenType.EndReplacementSegment)
{
body.AddRange(ReadReplacementBody(reader, replacementKeyToken));
}
else if (closeReplacementToken.TokenType == DocumentTokenType.QuickTerminateReplacementSegment)
{
// do nothing, there is no body when the quick termination replacement segment is used
}
else
{
throw Unexpected(string.Format("'{0}' or '{1}'", DocumentToken.GetTokenTypeValue(DocumentTokenType.EndReplacementSegment), DocumentToken.GetTokenTypeValue(DocumentTokenType.QuickTerminateReplacementSegment)), closeReplacementToken);
}
IDocumentExpressionProvider provider;
if (this.expressionProviders.TryGetValue(replacementKeyToken.Value, out provider) == false)
{
provider = new EvalExpressionProvider();
}
var context = new DocumentExpressionContext
{
OpenToken = openToken,
CloseToken = closeReplacementToken,
Parameters = parameters.AsReadOnly(),
Body = body.AsReadOnly(),
ReplacementKeyToken = replacementKeyToken,
};
var expression = provider.CreateExpression(context);
ret.Add(expression);
}
/// <summary>
/// Parses the given tokens into document expressions that can then be evaluated against a data context.
/// </summary>
/// <param name="tokens">The tokens to parse</param>
/// <returns>a list of document expressions</returns>
public List <IDocumentExpression> Parse(IEnumerable <DocumentToken> tokens)
{
List <IDocumentExpression> ret = new List <IDocumentExpression>();
TokenReader <DocumentToken> reader = new TokenReader <DocumentToken>(tokens);
while (reader.CanAdvance())
{
if (reader.Peek().TokenType == DocumentTokenType.BeginReplacementSegment)
{
ParseReplacement(reader, ret);
}
else
{
var plain = new PlainTextDocumentExpression(reader.Advance());
ret.Add(plain);
}
}
return(ret);
}