/** Rewrite alt to have a synpred as first element;
* (xxx)=>xxx
* but only if they didn't specify one manually.
*/
protected virtual void PrefixWithSynPred(GrammarAST alt)
{
// if they want backtracking and it's not a lexer rule in combined grammar
string autoBacktrack = (string)Grammar.GetBlockOption(currentBlockAST, "backtrack");
if (autoBacktrack == null)
{
autoBacktrack = (string)Grammar.GetOption("backtrack");
}
if (autoBacktrack != null && autoBacktrack.Equals("true") &&
!(GrammarType == GrammarType.Combined &&
Rule.GetRuleType(currentRuleName) == RuleType.Lexer) &&
alt.GetChild(0).Type != SYN_SEMPRED)
{
// duplicate alt and make a synpred block around that dup'd alt
GrammarAST synpredBlockAST = CreateBlockFromDupAlt(alt);
// Create a BACKTRACK_SEMPRED node as if user had typed this in
// Effectively we replace (xxx)=>xxx with {synpredxxx}? xxx
GrammarAST synpredAST = CreateSynSemPredFromBlock(synpredBlockAST,
BACKTRACK_SEMPRED);
// insert BACKTRACK_SEMPRED as first element of alt
//synpredAST.getLastSibling().setNextSibling( alt.getFirstChild() );
//synpredAST.addChild( alt.getFirstChild() );
//alt.setFirstChild( synpredAST );
GrammarAST[] children = alt.GetChildrenAsArray();
adaptor.SetChild(alt, 0, synpredAST);
for (int i = 0; i < children.Length; i++)
{
if (i < children.Length - 1)
{
adaptor.SetChild(alt, i + 1, children[i]);
}
else
{
adaptor.AddChild(alt, children[i]);
}
}
}
}
protected StringTemplate GetTokenElementST(string name,
string elementName,
GrammarAST elementAST,
GrammarAST ast_suffix,
string label)
{
bool tryUnchecked = false;
if (name == "matchSet" && !string.IsNullOrEmpty(elementAST.enclosingRuleName) && Rule.GetRuleType(elementAST.enclosingRuleName) == RuleType.Lexer)
{
if ((elementAST.Parent.Type == ANTLRLexer.ALT && elementAST.Parent.Parent.Parent.Type == RULE && elementAST.Parent.Parent.ChildCount == 2) ||
(elementAST.Parent.Type == ANTLRLexer.NOT && elementAST.Parent.Parent.Parent.Parent.Type == RULE && elementAST.Parent.Parent.Parent.ChildCount == 2))
{
// single alt at the start of the rule needs to be checked
}
else
{
tryUnchecked = true;
}
}
string suffix = GetSTSuffix(elementAST, ast_suffix, label);
// if we're building trees and there is no label, gen a label
// unless we're in a synpred rule.
Rule r = grammar.GetRule(currentRuleName);
if ((grammar.BuildAST || suffix.Length > 0) && label == null &&
(r == null || !r.isSynPred))
{
label = generator.CreateUniqueLabel(elementName);
CommonToken labelTok = new CommonToken(ANTLRParser.ID, label);
grammar.DefineTokenRefLabel(currentRuleName, labelTok, elementAST);
}
StringTemplate elementST = null;
if (tryUnchecked && templates.IsDefined(name + "Unchecked" + suffix))
{
elementST = templates.GetInstanceOf(name + "Unchecked" + suffix);
}
if (elementST == null)
{
elementST = templates.GetInstanceOf(name + suffix);
}
if (label != null)
{
elementST.SetAttribute("label", label);
}
return(elementST);
}