protected virtual GrammarAST ExpandOptionalQuantifiersForAlt(GrammarAST alt)
{
if (alt.ChildCount == 0)
{
return(null);
}
if (alt.GetChild(0).Type == ANTLRParser.OPTIONAL)
{
GrammarAST root = (GrammarAST)adaptor.Nil();
GrammarAST alt2 = alt.DupTree();
alt2.DeleteChild(0);
if (alt2.ChildCount == 0)
{
adaptor.AddChild(alt2, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
alt.SetChild(0, alt.GetChild(0).GetChild(0));
if (alt.GetChild(0).Type == ANTLRParser.BLOCK && alt.GetChild(0).ChildCount == 1 && alt.GetChild(0).GetChild(0).Type == ANTLRParser.ALT)
{
GrammarAST list = (GrammarAST)adaptor.Nil();
foreach (object tree in ((GrammarAST)alt.GetChild(0).GetChild(0)).Children)
{
adaptor.AddChild(list, tree);
}
adaptor.ReplaceChildren(alt, 0, 0, list);
}
adaptor.AddChild(root, alt);
adaptor.AddChild(root, alt2);
return(root);
}
else if (alt.GetChild(0).Type == ANTLRParser.CLOSURE)
{
GrammarAST root = (GrammarAST)adaptor.Nil();
GrammarAST alt2 = alt.DupTree();
alt2.DeleteChild(0);
if (alt2.ChildCount == 0)
{
adaptor.AddChild(alt2, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
PlusBlockAST plusBlockAST = new PlusBlockAST(ANTLRParser.POSITIVE_CLOSURE, adaptor.CreateToken(ANTLRParser.POSITIVE_CLOSURE, "+"), null);
for (int i = 0; i < alt.GetChild(0).ChildCount; i++)
{
plusBlockAST.AddChild(alt.GetChild(0).GetChild(i));
}
alt.SetChild(0, plusBlockAST);
adaptor.AddChild(root, alt);
adaptor.AddChild(root, alt2);
return(root);
}
return(alt);
}
protected virtual GrammarAST TranslateLeftFactoredElement(GrammarAST element, 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.");
}
if (mode == DecisionFactorMode.COMBINED_FACTOR)
{
throw new InvalidOperationException("Cannot return a combined answer.");
}
Debug.Assert(!mode.IncludeFactoredAlts() || !mode.IncludeUnfactoredAlts());
switch (element.Type)
{
case ANTLRParser.ASSIGN:
case ANTLRParser.PLUS_ASSIGN:
{
/* label=a
*
* ==>
*
* factoredElement label=a_factored
*/
GrammarAST translatedChildElement = TranslateLeftFactoredElement((GrammarAST)element.GetChild(1), factoredRule, variant, mode, includeFactoredElement);
if (translatedChildElement == null)
{
return(null);
}
RuleAST ruleAST = (RuleAST)element.GetAncestor(ANTLRParser.RULE);
#if false
LOGGER.log(Level.WARNING, "Could not left factor ''{0}'' out of decision in rule ''{1}'': labeled rule references are not yet supported.",
new object[] { factoredRule, ruleAST.GetChild(0).Text });
#endif
return(null);
//if (!translatedChildElement.IsNil)
//{
// GrammarAST root = (GrammarAST)adaptor.Nil();
// object factoredElement = translatedChildElement;
// if (outerRule)
// {
// adaptor.AddChild(root, factoredElement);
// }
// string action = string.Format("_localctx.{0} = (ContextType)_localctx.getParent().getChild(_localctx.getParent().getChildCount() - 1);", element.GetChild(0).Text);
// adaptor.AddChild(root, new ActionAST(adaptor.CreateToken(ANTLRParser.ACTION, action)));
// return root;
//}
//else
//{
// GrammarAST root = (GrammarAST)adaptor.Nil();
// object factoredElement = adaptor.DeleteChild(translatedChildElement, 0);
// if (outerRule)
// {
// adaptor.AddChild(root, factoredElement);
// }
// adaptor.AddChild(root, element);
// adaptor.ReplaceChildren(element, 1, 1, translatedChildElement);
// return root;
//}
}
case ANTLRParser.RULE_REF:
{
if (factoredRule.Equals(element.Token.Text))
{
if (!mode.IncludeFactoredAlts())
{
return(null);
}
if (includeFactoredElement)
{
// this element is already left factored
return(element);
}
GrammarAST root1 = (GrammarAST)adaptor.Nil();
root1.AddChild((ITree)adaptor.Create(TokenConstants.Epsilon, "EPSILON"));
root1.DeleteChild(0);
return(root1);
}
Rule targetRule;
if (!_rules.TryGetValue(element.Token.Text, out targetRule))
{
return(null);
}
RuleVariants ruleVariants = CreateLeftFactoredRuleVariant(targetRule, factoredRule);
switch (ruleVariants)
{
case RuleVariants.NONE:
if (!mode.IncludeUnfactoredAlts())
{
return(null);
}
// just call the original rule (leave the element unchanged)
return(element);
case RuleVariants.FULLY_FACTORED:
if (!mode.IncludeFactoredAlts())
{
return(null);
}
break;
case RuleVariants.PARTIALLY_FACTORED:
break;
default:
throw new InvalidOperationException();
}
string marker = mode.IncludeFactoredAlts() ? ATNSimulator.RuleLfVariantMarker : ATNSimulator.RuleNolfVariantMarker;
element.SetText(element.Text + marker + factoredRule);
GrammarAST root = (GrammarAST)adaptor.Nil();
if (includeFactoredElement)
{
Debug.Assert(mode.IncludeFactoredAlts());
RuleRefAST factoredRuleRef = new RuleRefAST(adaptor.CreateToken(ANTLRParser.RULE_REF, factoredRule));
factoredRuleRef.SetOption(SUPPRESS_ACCESSOR, (GrammarAST)adaptor.Create(ANTLRParser.ID, "true"));
Rule factoredRuleDef = _rules[factoredRule];
if (factoredRuleDef is LeftRecursiveRule)
{
factoredRuleRef.SetOption(LeftRecursiveRuleTransformer.PRECEDENCE_OPTION_NAME, (GrammarAST)adaptor.Create(ANTLRParser.INT, "0"));
}
if (factoredRuleDef.args != null && factoredRuleDef.args.Size() > 0)
{
throw new NotImplementedException("Cannot left-factor rules with arguments yet.");
}
adaptor.AddChild(root, factoredRuleRef);
}
adaptor.AddChild(root, element);
return(root);
}
case ANTLRParser.BLOCK:
{
GrammarAST cloned = element.DupTree();
if (!TranslateLeftFactoredDecision(cloned, factoredRule, variant, mode, includeFactoredElement))
{
return(null);
}
if (cloned.ChildCount != 1)
{
return(null);
}
GrammarAST root = (GrammarAST)adaptor.Nil();
for (int i = 0; i < cloned.GetChild(0).ChildCount; i++)
{
adaptor.AddChild(root, cloned.GetChild(0).GetChild(i));
}
return(root);
}
case ANTLRParser.POSITIVE_CLOSURE:
{
/* a+
*
* =>
*
* factoredElement a_factored a*
*/
GrammarAST originalChildElement = (GrammarAST)element.GetChild(0);
GrammarAST translatedElement = TranslateLeftFactoredElement(originalChildElement.DupTree(), factoredRule, variant, mode, includeFactoredElement);
if (translatedElement == null)
{
return(null);
}
GrammarAST closure = new StarBlockAST(ANTLRParser.CLOSURE, adaptor.CreateToken(ANTLRParser.CLOSURE, "CLOSURE"), null);
adaptor.AddChild(closure, originalChildElement);
GrammarAST root = (GrammarAST)adaptor.Nil();
if (mode.IncludeFactoredAlts())
{
if (includeFactoredElement)
{
object factoredElement = adaptor.DeleteChild(translatedElement, 0);
adaptor.AddChild(root, factoredElement);
}
}
adaptor.AddChild(root, translatedElement);
adaptor.AddChild(root, closure);
return(root);
}
case ANTLRParser.CLOSURE:
case ANTLRParser.OPTIONAL:
// not yet supported
if (mode.IncludeUnfactoredAlts())
{
return(element);
}
return(null);
case ANTLRParser.DOT:
// ref to imported grammar, not yet supported
if (mode.IncludeUnfactoredAlts())
{
return(element);
}
return(null);
case ANTLRParser.ACTION:
case ANTLRParser.SEMPRED:
if (mode.IncludeUnfactoredAlts())
{
return(element);
}
return(null);
case ANTLRParser.WILDCARD:
case ANTLRParser.STRING_LITERAL:
case ANTLRParser.TOKEN_REF:
case ANTLRParser.NOT:
// terminals
if (mode.IncludeUnfactoredAlts())
{
return(element);
}
return(null);
case ANTLRParser.EPSILON:
// empty tree
if (mode.IncludeUnfactoredAlts())
{
return(element);
}
return(null);
default:
// unknown
return(null);
}
}
protected virtual bool TranslateLeftFactoredDecision(GrammarAST block, 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.");
}
if (!ExpandOptionalQuantifiersForBlock(block, variant))
{
return(false);
}
IList <GrammarAST> alternatives = block.GetAllChildrenWithType(ANTLRParser.ALT);
GrammarAST[] factoredAlternatives = new GrammarAST[alternatives.Count];
GrammarAST[] unfactoredAlternatives = new GrammarAST[alternatives.Count];
IntervalSet factoredIntervals = new IntervalSet();
IntervalSet unfactoredIntervals = new IntervalSet();
for (int i = 0; i < alternatives.Count; i++)
{
GrammarAST alternative = alternatives[i];
if (mode.IncludeUnfactoredAlts())
{
GrammarAST unfactoredAlt = TranslateLeftFactoredAlternative(alternative.DupTree(), factoredRule, variant, DecisionFactorMode.PARTIAL_UNFACTORED, false);
unfactoredAlternatives[i] = unfactoredAlt;
if (unfactoredAlt != null)
{
unfactoredIntervals.Add(i);
}
}
if (mode.IncludeFactoredAlts())
{
GrammarAST factoredAlt = TranslateLeftFactoredAlternative(alternative, factoredRule, variant, mode == DecisionFactorMode.COMBINED_FACTOR ? DecisionFactorMode.PARTIAL_FACTORED : DecisionFactorMode.FULL_FACTOR, includeFactoredElement);
factoredAlternatives[i] = factoredAlt;
if (factoredAlt != null)
{
factoredIntervals.Add(alternative.ChildIndex);
}
}
}
if (factoredIntervals.IsNil && !mode.IncludeUnfactoredAlts())
{
return(false);
}
else if (unfactoredIntervals.IsNil && !mode.IncludeFactoredAlts())
{
return(false);
}
if (unfactoredIntervals.IsNil && factoredIntervals.Count == alternatives.Count && mode.IncludeFactoredAlts() && !includeFactoredElement)
{
for (int i = 0; i < factoredAlternatives.Length; i++)
{
GrammarAST translatedAlt = factoredAlternatives[i];
if (translatedAlt.ChildCount == 0)
{
adaptor.AddChild(translatedAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.SetChild(block, i, translatedAlt);
}
return(true);
}
else if (factoredIntervals.IsNil && unfactoredIntervals.Count == alternatives.Count && mode.IncludeUnfactoredAlts())
{
for (int i = 0; i < unfactoredAlternatives.Length; i++)
{
GrammarAST translatedAlt = unfactoredAlternatives[i];
if (translatedAlt.ChildCount == 0)
{
adaptor.AddChild(translatedAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.SetChild(block, i, translatedAlt);
}
return(true);
}
if (mode == DecisionFactorMode.FULL_FACTOR)
{
return(false);
}
/* for a, b, c being arbitrary `element` trees, this block performs
* this transformation:
*
* factoredElement a
* | factoredElement b
* | factoredElement c
* | ...
*
* ==>
*
* factoredElement (a | b | c | ...)
*/
GrammarAST newChildren = (GrammarAST)adaptor.Nil();
for (int i = 0; i < alternatives.Count; i++)
{
if (mode.IncludeFactoredAlts() && factoredIntervals.Contains(i))
{
bool combineWithPrevious = i > 0 && factoredIntervals.Contains(i - 1) && (!mode.IncludeUnfactoredAlts() || !unfactoredIntervals.Contains(i - 1));
if (combineWithPrevious)
{
GrammarAST translatedAlt = factoredAlternatives[i];
if (translatedAlt.ChildCount == 0)
{
adaptor.AddChild(translatedAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
GrammarAST previous = (GrammarAST)newChildren.GetChild(newChildren.ChildCount - 1);
#if false
if (LOGGER.isLoggable(Level.FINE))
{
LOGGER.log(Level.FINE, previous.ToStringTree());
LOGGER.log(Level.FINE, translatedAlt.ToStringTree());
}
#endif
if (previous.ChildCount == 1 || previous.GetChild(1).Type != ANTLRParser.BLOCK)
{
GrammarAST newBlock = new BlockAST(adaptor.CreateToken(ANTLRParser.BLOCK, "BLOCK"));
GrammarAST newAlt = new AltAST(adaptor.CreateToken(ANTLRParser.ALT, "ALT"));
adaptor.AddChild(newBlock, newAlt);
while (previous.ChildCount > 1)
{
adaptor.AddChild(newAlt, previous.DeleteChild(1));
}
if (newAlt.ChildCount == 0)
{
adaptor.AddChild(newAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.AddChild(previous, newBlock);
}
if (translatedAlt.ChildCount == 1 || translatedAlt.GetChild(1).Type != ANTLRParser.BLOCK)
{
GrammarAST newBlock = new BlockAST(adaptor.CreateToken(ANTLRParser.BLOCK, "BLOCK"));
GrammarAST newAlt = new AltAST(adaptor.CreateToken(ANTLRParser.ALT, "ALT"));
adaptor.AddChild(newBlock, newAlt);
while (translatedAlt.ChildCount > 1)
{
adaptor.AddChild(newAlt, translatedAlt.DeleteChild(1));
}
if (newAlt.ChildCount == 0)
{
adaptor.AddChild(newAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.AddChild(translatedAlt, newBlock);
}
GrammarAST combinedBlock = (GrammarAST)previous.GetChild(1);
adaptor.AddChild(combinedBlock, translatedAlt.GetChild(1).GetChild(0));
#if false
if (LOGGER.isLoggable(Level.FINE))
{
LOGGER.log(Level.FINE, previous.ToStringTree());
}
#endif
}
else
{
GrammarAST translatedAlt = factoredAlternatives[i];
if (translatedAlt.ChildCount == 0)
{
adaptor.AddChild(translatedAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.AddChild(newChildren, translatedAlt);
}
}
if (mode.IncludeUnfactoredAlts() && unfactoredIntervals.Contains(i))
{
GrammarAST translatedAlt = unfactoredAlternatives[i];
if (translatedAlt.ChildCount == 0)
{
adaptor.AddChild(translatedAlt, adaptor.Create(ANTLRParser.EPSILON, "EPSILON"));
}
adaptor.AddChild(newChildren, translatedAlt);
}
}
adaptor.ReplaceChildren(block, 0, block.ChildCount - 1, newChildren);
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);
}
