private void InitStartingTokensWithChoice(Rule <IN> rule, ChoiceClause <IN> choice, Dictionary <string, NonTerminal <IN> > nonTerminals)
{
foreach (var alternate in choice.Choices)
{
if (alternate is TerminalClause <IN> term)
{
InitStartingTokensWithTerminal(rule, term);
}
else if (alternate is NonTerminalClause <IN> nonTerminal)
{
InitStartingTokensWithNonTerminal(rule, nonTerminal, nonTerminals);
}
}
}
public SyntaxParseResult <IN> ParseChoice(IList <Token <IN> > tokens, ChoiceClause <IN> choice,
int position)
{
var currentPosition = position;
SyntaxParseResult <IN> result = new SyntaxParseResult <IN>()
{
IsError = true,
IsEnded = false,
EndingPosition = currentPosition
};
foreach (var alternate in choice.Choices)
{
if (alternate is TerminalClause <IN> terminalAlternate)
{
result = ParseTerminal(tokens, terminalAlternate, currentPosition);
}
else if (alternate is NonTerminalClause <IN> nonTerminalAlternate)
{
result = ParseNonTerminal(tokens, nonTerminalAlternate, currentPosition);
}
else
{
throw new InvalidOperationException("unable to apply repeater inside " + choice.GetType().Name);
}
if (result.IsOk)
{
if (choice.IsTerminalChoice && choice.IsDiscarded && result.Root is SyntaxLeaf <IN> leaf)
{
var discardedToken = new SyntaxLeaf <IN>(leaf.Token, true);
result.Root = discardedToken;
}
return(result);
}
}
if (result.IsError && choice.IsTerminalChoice)
{
var terminalAlternates = choice.Choices.Cast <TerminalClause <IN> >();
var expected = terminalAlternates.Select(x => x.ExpectedToken).ToList();
result.Errors.Add(new UnexpectedTokenSyntaxError <IN>(tokens[currentPosition], expected.ToArray()));
}
return(result);
}
public IClause <IN> AlternateClause(ChoiceClause <IN> choices)
{
choices.IsDiscarded = false;
return(choices);
}
public IClause <IN> AlternateDiscardedClause(ChoiceClause <IN> choices, Token <EbnfTokenGeneric> discarded)
{
choices.IsDiscarded = true;
return(choices);
}
public IClause <IN> ChoiceOptional(ChoiceClause <IN> choices, Token <EbnfTokenGeneric> discardOption)
{
return(new OptionClause <IN>(choices));
}
public IClause <IN> ChoiceZeroOrMore(ChoiceClause <IN> choices, Token <EbnfTokenGeneric> discardZeroOrMore)
{
return(new ZeroOrMoreClause <IN>(choices));
}
public IClause <IN> ChoicesMany(Token <EbnfTokenGeneric> head, Token <EbnfTokenGeneric> discardOr, ChoiceClause <IN> tail)
{
var headClause = BuildTerminalOrNonTerimal(head.Value);
return(new ChoiceClause <IN>(headClause, tail.Choices));
}
public GroupClause <IN> GroupChoiceClause(ChoiceClause <IN> choices)
{
return(new GroupClause <IN>(choices));
}
