protected virtual GrammarAST TranslateLeftFactoredAlternative(GrammarAST alternative, string factoredRule, bool variant, DecisionFactorMode mode, bool includeFactoredElement)
{
if (mode == DecisionFactorMode.PARTIAL_UNFACTORED && includeFactoredElement)
{
throw new ArgumentException("Cannot include the factored element in unfactored alternatives.");
}
else if (mode == DecisionFactorMode.COMBINED_FACTOR && !includeFactoredElement)
{
throw new ArgumentException("Cannot return a combined answer without the factored element.");
}
Debug.Assert(alternative.ChildCount > 0);
if (alternative.GetChild(0).Type == ANTLRParser.EPSILON)
{
if (mode == DecisionFactorMode.PARTIAL_UNFACTORED)
{
return alternative;
}
return null;
}
GrammarAST translatedElement = TranslateLeftFactoredElement((GrammarAST)alternative.GetChild(0), factoredRule, variant, mode, includeFactoredElement);
if (translatedElement == null)
{
return null;
}
alternative.ReplaceChildren(0, 0, translatedElement);
if (alternative.ChildCount == 0)
{
adaptor.AddChild(alternative, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
Debug.Assert(alternative.ChildCount > 0);
return alternative;
}
protected virtual bool ExpandOptionalQuantifiersForBlock(GrammarAST block, bool variant)
{
IList<GrammarAST> children = new List<GrammarAST>();
for (int i = 0; i < block.ChildCount; i++)
{
GrammarAST child = (GrammarAST)block.GetChild(i);
if (child.Type != ANTLRParser.ALT)
{
children.Add(child);
continue;
}
GrammarAST expandedAlt = ExpandOptionalQuantifiersForAlt(child);
if (expandedAlt == null)
{
return false;
}
children.Add(expandedAlt);
}
GrammarAST newChildren = (GrammarAST)adaptor.Nil();
newChildren.AddChildren(children);
block.ReplaceChildren(0, block.ChildCount - 1, newChildren);
block.FreshenParentAndChildIndexesDeeply();
if (!variant && block.Parent is RuleAST)
{
RuleAST ruleAST = (RuleAST)block.Parent;
string ruleName = ruleAST.GetChild(0).Text;
Rule r = _rules[ruleName];
IList<GrammarAST> blockAlts = block.GetAllChildrenWithType(ANTLRParser.ALT);
r.numberOfAlts = blockAlts.Count;
r.alt = new Alternative[blockAlts.Count + 1];
for (int i = 0; i < blockAlts.Count; i++)
{
r.alt[i + 1] = new Alternative(r, i + 1);
r.alt[i + 1].ast = (AltAST)blockAlts[i];
}
}
return true;
}
