private static bool TryTakeRuleSequence(RuleTokenKeeper tokenKeeper, out ApplyIfRuleClause clause)
{
var work = new RuleTokenKeeper(tokenKeeper);
if (TryTakeRuleClause(work, out var left))
{
if (work.Next.TokenType == ApplyIfTokenType.Comma)
{
ApplyIfRuleClause right;
work.Take();
if (TryTakeRuleSequence(work, out right) || TryTakeRuleClause(work, out right))
{
if (work.Finished)
{
tokenKeeper.Swap(work);
clause = new RuleSequenceClause(left, right);
return(true);
}
}
}
}
clause = null;
return(false);
}
internal static bool TryTakeEntityReference(RuleTokenKeeper tokenKeeper, out EntityReference clause)
{
var next = tokenKeeper.Next;
if (next.TokenType == ApplyIfTokenType.Identifier)
{
var work = new RuleTokenKeeper(tokenKeeper);
var entity = work.Take().Text;
if (work.Next.TokenType == ApplyIfTokenType.Period)
{
work.Take();
if (work.Next.TokenType == ApplyIfTokenType.Identifier)
{
var field = work.Take().Text;
tokenKeeper.Swap(work);
clause = new EntityReference(entity, field);
return(true);
}
}
clause = null;
return(false);
}
clause = null;
return(false);
}
private static bool TryTakeMatch(RuleTokenKeeper tokenKeeper, out ApplyIfRuleClause clause)
{
var next = tokenKeeper.Next;
if (next.TokenType == ApplyIfTokenType.Match)
{
var work = new RuleTokenKeeper(tokenKeeper);
work.Take();
if (work.Next.TokenType == ApplyIfTokenType.OpenParen)
{
work.Take();
if (EntityReferenceParser.TryTakeEntityReference(work, out var entityReference))
{
if (work.Next.TokenType == ApplyIfTokenType.CloseParen)
{
work.Take();
}
tokenKeeper.Swap(work);
clause = new MatchClause(entityReference);
return(true);
}
}
}
clause = null;
return(false);
}