private IParseResult <ExpressionMetaData> TryGetGroupExpression(ITokenStream tokenStream, out IExpression expression)
{
tokenStream.Pop();
var closePrecedenceToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
if (closePrecedenceToken == RegexTokenType.ClosePrecedence)
{
tokenStream.Pop();
expression = new EmptyExpression();
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, new ExpressionMetaData()));
}
var unionExpressionResult = TryGetUnionExpression <UnionExpression>(tokenStream, out expression);
if (!unionExpressionResult.IsSuccess)
{
return(unionExpressionResult);
}
closePrecedenceToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
if (closePrecedenceToken != RegexTokenType.ClosePrecedence)
{
return(new FailureParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, RegSeedErrorType.ClosePrecedenceExpected));
}
tokenStream.Pop();
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, unionExpressionResult.Value));
}
private static IntegerInterval GetRepeatConcatenationInterval(ITokenStream tokenStream)
{
var nextToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
return(nextToken != RegexTokenType.IntegerRange
? new IntegerInterval(1)
: tokenStream.Pop().GetValue <IntegerInterval>());
}
private IParseResult <ExpressionMetaData> TryGetElementaryExpression(ITokenStream tokenStream, out IExpression expression)
{
expression = null;
var nextToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
return(_regexTokenToExpressionMapper.TryGetValue(nextToken, out var tryGetElementaryExpression)
? tryGetElementaryExpression(tokenStream, out expression)
: new FailureParseResult <ExpressionMetaData>(tokenStream.CurrentPosition));
}
private IParseResult <ExpressionMetaData> TryGetCharacterClassExpression(ITokenStream tokenStream, out IExpression expression)
{
expression = null;
var nextTokenType = tokenStream.Pop().GetType <RegexTokenType>();
var getComplement = nextTokenType == RegexTokenType.OpenNegateCharacterClass;
nextTokenType = tokenStream.LookAhead(0).GetType <RegexTokenType>();
var characters = new List <string>();
while (nextTokenType == RegexTokenType.Character || nextTokenType == RegexTokenType.CharacterRange)
{
var nextToken = tokenStream.Pop();
if (nextToken.GetType <RegexTokenType>() == RegexTokenType.Character)
{
characters.Add(nextToken.GetValue <string>());
}
else
{
characters.AddRange(nextToken.GetValue <CharacterRange>().Characters);
}
nextTokenType = tokenStream.LookAhead(0).GetType <RegexTokenType>();
}
if (nextTokenType != RegexTokenType.CloseCharacterClass)
{
return(new FailureParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, RegSeedErrorType.CloseCharacterClassExpected));
}
tokenStream.Pop();
var characterClassExpression = new CharacterClassExpression(_alphabet, _random, _maxCharClassInverseLength);
characterClassExpression.AddCharacters(characters);
expression = getComplement ? characterClassExpression.GetComplement() : characterClassExpression;
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, new ExpressionMetaData()));
}
private IParseResult <ExpressionMetaData> TryGetSubExpressionList(RegexTokenType token, ITokenStream tokenStream, out List <IExpression> subExpressionList)
{
subExpressionList = null;
var subExpressionResult = _regexTokenToExpressionListMapper[token](tokenStream, out var subExpression);
if (!subExpressionResult.IsSuccess)
{
return(subExpressionResult);
}
subExpressionList = new List <IExpression> {
subExpression
};
var nextToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
var metaData = subExpressionResult.Value;
while (nextToken == token)
{
if (token == RegexTokenType.Intersection)
{
metaData.HasIntersection = true;
}
tokenStream.Pop();
subExpressionResult = _regexTokenToExpressionListMapper[token](tokenStream, out subExpression);
if (!subExpressionResult.IsSuccess)
{
return(subExpressionResult);
}
metaData.UpdateWith(subExpressionResult.Value);
subExpressionList.Add(subExpression);
nextToken = tokenStream.LookAhead(0).GetType <RegexTokenType>();
}
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, metaData));
}
private IParseResult <ExpressionMetaData> TryGetExpressionListSeparatedByToken <TExpression>(ITokenStream tokenStream, out IExpression expression)
{
expression = new EmptyExpression();
if (tokenStream.LookAhead(0).GetType <RegexTokenType>() == RegexTokenType.EndOfStream)
{
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, new ExpressionMetaData()));
}
var token = _expressionTokenTypeMapper[typeof(TExpression)];
var subExpressionResult = TryGetSubExpressionList(token, tokenStream, out var subExpressionList);
if (!subExpressionResult.IsSuccess)
{
return(subExpressionResult);
}
expression = CreateExpression <TExpression>(subExpressionList);
return(new SuccessParseResult <ExpressionMetaData>(tokenStream.CurrentPosition, subExpressionResult.Value));
}