protected virtual Handle MakeBlock([NotNull] BlockStartState start, [NotNull] BlockAST blkAST, [NotNull] IList <Handle> alts)
{
start.sll = IsSLLDecision(blkAST);
BlockEndState end = NewState <BlockEndState>(blkAST);
start.endState = end;
foreach (Handle alt in alts)
{
// hook alts up to decision block
Epsilon(start, alt.left);
Epsilon(alt.right, end);
// no back link in ATN so must walk entire alt to see if we can
// strip out the epsilon to 'end' state
TailEpsilonRemover opt = new TailEpsilonRemover(atn);
opt.Visit(alt.left);
}
Handle h = new Handle(start, end);
// FASerializer ser = new FASerializer(g, h.left);
// System.out.println(blkAST.toStringTree()+":\n"+ser);
blkAST.atnState = start;
return(h);
}
public virtual Handle Optional([NotNull] GrammarAST optAST, [NotNull] Handle blk)
{
BlockStartState blkStart = (BlockStartState)blk.left;
ATNState blkEnd = blk.right;
preventEpsilonOptionalBlocks.Add(Tuple.Create <Rule, ATNState, ATNState>(currentRule, blkStart, blkEnd));
bool greedy = ((QuantifierAST)optAST).GetGreedy();
blkStart.sll = false; // no way to express SLL restriction
blkStart.nonGreedy = !greedy;
Epsilon(blkStart, blk.right, !greedy);
optAST.atnState = blk.left;
return(blk);
}
public virtual Handle Block([NotNull] BlockAST blkAST, [NotNull] GrammarAST ebnfRoot, [NotNull] IList <Handle> alts)
{
if (ebnfRoot == null)
{
if (alts.Count == 1)
{
Handle h = alts[0];
blkAST.atnState = h.left;
return(h);
}
BlockStartState start = NewState <BasicBlockStartState>(blkAST);
if (alts.Count > 1)
{
atn.DefineDecisionState(start);
}
return(MakeBlock(start, blkAST, alts));
}
switch (ebnfRoot.Type)
{
case ANTLRParser.OPTIONAL:
BlockStartState start = NewState <BasicBlockStartState>(blkAST);
atn.DefineDecisionState(start);
Handle h = MakeBlock(start, blkAST, alts);
return(Optional(ebnfRoot, h));
case ANTLRParser.CLOSURE:
BlockStartState star = NewState <StarBlockStartState>(ebnfRoot);
if (alts.Count > 1)
{
atn.DefineDecisionState(star);
}
h = MakeBlock(star, blkAST, alts);
return(Star(ebnfRoot, h));
case ANTLRParser.POSITIVE_CLOSURE:
PlusBlockStartState plus = NewState <PlusBlockStartState>(ebnfRoot);
if (alts.Count > 1)
{
atn.DefineDecisionState(plus);
}
h = MakeBlock(plus, blkAST, alts);
return(Plus(ebnfRoot, h));
}
return(null);
}
