public static ExpressionToken TryParse(Scope scope, IEnumerable <string> endTokens,
WordTokenCallback wordCallback = null, DataType expectedDataType = null)
{
var code = scope.Code;
code.SkipWhiteSpace();
var startPos = code.Position;
// Statement breaking tokens
if (code.PeekExact(';') || code.PeekExact('{') || code.PeekExact('}'))
{
return(null);
}
// Caller-specific end tokens
if (endTokens != null)
{
code.Peek();
if (endTokens.Contains(code.Text))
{
return(null);
}
}
var exp = new ExpressionToken(scope);
var dataTypeArgs = new DataType.ParseArgs
{
Code = code,
DataTypeCallback = (name) =>
{
return(scope.DefinitionProvider.GetAny <DataTypeDefinition>(code.Position, name).FirstOrDefault());
},
VariableCallback = (name) =>
{
return(scope.DefinitionProvider.GetLocal <VariableDefinition>(code.Position, name).FirstOrDefault());
},
Scope = scope,
TokenCreateCallback = (token) =>
{
exp.AddToken(token);
},
VisibleModel = true
};
var abortParsing = false;
var parseDataType = expectedDataType;
while (!code.EndOfFile && !abortParsing)
{
// Statement breaking tokens
if (code.PeekExact(';') || code.PeekExact('{') || code.PeekExact('}'))
{
break;
}
if (endTokens != null && code.Peek() && endTokens.Contains(code.Text))
{
break;
}
if (!code.Read())
{
break;
}
switch (code.Type)
{
case CodeType.Word:
{
var word = code.Text;
var wordSpan = code.Span;
Token token;
if (wordCallback != null && (token = wordCallback(word, wordSpan)) != null)
{
exp.AddToken(token);
}
else if (parseDataType != null && parseDataType.HasCompletionOptions && parseDataType.IsValidEnumOption(word))
{
exp.AddToken(new EnumOptionToken(scope, wordSpan, word, parseDataType));
}
else
{
var oldPos = code.Position;
code.Position = wordSpan.Start; // DataType.TryParse() needs to be before the first word
var dt = DataType.TryParse(dataTypeArgs);
if (dt == null)
{
code.Position = oldPos;
var wordToken = ProcessWord(exp, scope, word, wordSpan);
if (wordToken != null)
{
exp.AddToken(wordToken);
}
else
{
code.Position = wordSpan.Start;
abortParsing = true;
}
}
}
}
break;
case CodeType.Number:
exp.AddToken(new NumberToken(scope, code.Span, code.Text));
break;
case CodeType.StringLiteral:
if (parseDataType != null && parseDataType.HasCompletionOptions && parseDataType.IsValidEnumOption(code.Text))
{
exp.AddToken(new EnumOptionToken(scope, code.Span, code.Text, parseDataType));
}
else
{
exp.AddToken(new StringLiteralToken(scope, code.Span, code.Text));
}
break;
case CodeType.Operator:
switch (code.Text)
{
case "(":
{
code.Position = code.Span.Start;
var bracketsToken = BracketsToken.Parse(scope, parseDataType);
if (bracketsToken.IsCast)
{
exp.AddToken(Statements.CastStatement.Parse(scope, bracketsToken, endTokens));
}
else
{
exp.AddToken(bracketsToken);
}
}
break;
case "{":
code.Position = code.Span.Start;
exp.AddToken(BracesToken.Parse(scope, null));
break;
case "[":
code.Position = code.Span.Start;
exp.AddToken(ArrayBracesToken.Parse(scope));
break;
case ",":
exp.AddToken(new DelimiterToken(scope, code.Span));
break;
case ".":
exp.AddToken(new DotToken(scope, code.Span));
break;
case "&":
exp.AddToken(new ReferenceToken(scope, code.Span));
break;
case "==":
case "!=":
case "<":
case "<=":
case ">":
case ">=":
if ((scope.Hint & ScopeHint.SuppressLogic) == 0)
{
if (exp.ChildrenCount > 0)
{
var dataType = exp.LastChild.ValueDataType;
if (dataType != null)
{
parseDataType = dataType;
}
}
exp.AddToken(ComparisonOperator.Parse(scope, exp.LastChild, new OperatorToken(scope, code.Span, code.Text), endTokens));
}
else
{
exp.AddToken(new OperatorToken(scope, code.Span, code.Text));
}
break;
case "=":
if ((scope.Hint & ScopeHint.SuppressLogic) == 0)
{
if (exp.ChildrenCount > 0)
{
var dataType = exp.LastChild.ValueDataType;
if (dataType != null)
{
parseDataType = dataType;
}
}
exp.AddToken(AssignmentOperator.Parse(scope, exp.LastChild, new OperatorToken(scope, code.Span, code.Text), endTokens));
}
else
{
exp.AddToken(new OperatorToken(scope, code.Span, code.Text));
}
break;
case "+=":
case "-=":
case "*=":
case "/=":
case "%=":
if ((scope.Hint & ScopeHint.SuppressLogic) == 0)
{
exp.AddToken(AssignmentOperator.Parse(scope, exp.LastChild, new OperatorToken(scope, code.Span, code.Text), endTokens));
}
else
{
exp.AddToken(new OperatorToken(scope, code.Span, code.Text));
}
break;
case "?":
parseDataType = expectedDataType;
exp.AddToken(ConditionalOperator.Parse(scope, exp.LastChild, new OperatorToken(scope, code.Span, code.Text),
endTokens, parseDataType));
break;
default:
exp.AddToken(new OperatorToken(scope, code.Span, code.Text));
break;
}
break;
case CodeType.Preprocessor:
exp.AddToken(new PreprocessorToken(scope, code.Span, code.Text));
break;
default:
exp.AddToken(new UnknownToken(scope, code.Span, code.Text));
break;
}
}
if (exp.ChildrenCount == 0)
{
return(null);
}
return(exp);
}