public override void DiscoverRule(RuleAST rule, GrammarAST ID, IList <GrammarAST> modifiers, ActionAST arg, ActionAST returns, GrammarAST thrws, GrammarAST options, ActionAST locals, IList <GrammarAST> actions, GrammarAST block) { int numAlts = block.ChildCount; Rule r; if (LeftRecursiveRuleAnalyzer.HasImmediateRecursiveRuleRefs(rule, ID.Text)) { r = new LeftRecursiveRule(g, ID.Text, rule); } else { r = new Rule(g, ID.Text, rule, numAlts); } rules[r.name] = r; if (arg != null) { r.args = ScopeParser.ParseTypedArgList(arg, arg.Text, g); r.args.type = AttributeDict.DictType.ARG; r.args.ast = arg; arg.resolver = r.alt[currentOuterAltNumber]; } if (returns != null) { r.retvals = ScopeParser.ParseTypedArgList(returns, returns.Text, g); r.retvals.type = AttributeDict.DictType.RET; r.retvals.ast = returns; } if (locals != null) { r.locals = ScopeParser.ParseTypedArgList(locals, locals.Text, g); r.locals.type = AttributeDict.DictType.LOCAL; r.locals.ast = locals; } foreach (GrammarAST a in actions) { // a = ^(AT ID ACTION) ActionAST action = (ActionAST)a.GetChild(1); r.namedActions[a.GetChild(0).Text] = action; action.resolver = r; } }
/** Return true if successful */ public virtual bool TranslateLeftRecursiveRule(GrammarRootAST ast, LeftRecursiveRule r, string language) { //tool.log("grammar", ruleAST.toStringTree()); GrammarAST prevRuleAST = r.ast; string ruleName = prevRuleAST.GetChild(0).Text; LeftRecursiveRuleAnalyzer leftRecursiveRuleWalker = new LeftRecursiveRuleAnalyzer(prevRuleAST, tool, ruleName, language); bool isLeftRec; try { //System.Console.WriteLine("TESTING ---------------\n" + // leftRecursiveRuleWalker.Text(ruleAST)); isLeftRec = leftRecursiveRuleWalker.rec_rule(); } catch (RecognitionException) { isLeftRec = false; // didn't match; oh well } if (!isLeftRec) { return(false); } // replace old rule's AST; first create text of altered rule GrammarAST RULES = (GrammarAST)ast.GetFirstChildWithType(ANTLRParser.RULES); string newRuleText = leftRecursiveRuleWalker.GetArtificialOpPrecRule(); //System.Console.WriteLine("created: " + newRuleText); // now parse within the context of the grammar that originally created // the AST we are transforming. This could be an imported grammar so // we cannot just reference this.g because the role might come from // the imported grammar and not the root grammar (this.g) RuleAST t = ParseArtificialRule(prevRuleAST.g, newRuleText); // reuse the name token from the original AST since it refers to the proper source location in the original grammar ((GrammarAST)t.GetChild(0)).Token = ((GrammarAST)prevRuleAST.GetChild(0)).Token; // update grammar AST and set rule's AST. RULES.SetChild(prevRuleAST.ChildIndex, t); r.ast = t; // Reduce sets in newly created rule tree GrammarTransformPipeline transform = new GrammarTransformPipeline(g, g.tool); transform.ReduceBlocksToSets(r.ast); transform.ExpandParameterizedLoops(r.ast); // Rerun semantic checks on the new rule RuleCollector ruleCollector = new RuleCollector(g); ruleCollector.Visit(t, "rule"); BasicSemanticChecks basics = new BasicSemanticChecks(g, ruleCollector); // disable the assoc element option checks because they are already // handled for the pre-transformed rule. basics.checkAssocElementOption = false; basics.Visit(t, "rule"); // track recursive alt info for codegen r.recPrimaryAlts = new List <LeftRecursiveRuleAltInfo>(); foreach (var altInfo in leftRecursiveRuleWalker.prefixAndOtherAlts) { r.recPrimaryAlts.Add(altInfo); } if (r.recPrimaryAlts.Count == 0) { tool.errMgr.GrammarError(ErrorType.NO_NON_LR_ALTS, g.fileName, ((GrammarAST)r.ast.GetChild(0)).Token, r.name); } r.recOpAlts = new OrderedHashMap <int, LeftRecursiveRuleAltInfo>(); foreach (var pair in leftRecursiveRuleWalker.binaryAlts) { r.recOpAlts[pair.Key] = pair.Value; } foreach (var pair in leftRecursiveRuleWalker.ternaryAlts) { r.recOpAlts[pair.Key] = pair.Value; } foreach (var pair in leftRecursiveRuleWalker.suffixAlts) { r.recOpAlts[pair.Key] = pair.Value; } // walk alt info records and set their altAST to point to appropriate ALT subtree // from freshly created AST SetAltASTPointers(r, t); // update Rule to just one alt and add prec alt ActionAST arg = (ActionAST)r.ast.GetFirstChildWithType(ANTLRParser.ARG_ACTION); if (arg != null) { r.args = ScopeParser.ParseTypedArgList(arg, arg.Text, g); r.args.type = AttributeDict.DictType.ARG; r.args.ast = arg; arg.resolver = r.alt[1]; // todo: isn't this Rule or something? } // define labels on recursive rule refs we delete; they don't point to nodes of course // these are so $label in action translation works foreach (System.Tuple <GrammarAST, string> pair in leftRecursiveRuleWalker.leftRecursiveRuleRefLabels) { GrammarAST labelNode = pair.Item1; GrammarAST labelOpNode = (GrammarAST)labelNode.Parent; GrammarAST elementNode = (GrammarAST)labelOpNode.GetChild(1); LabelElementPair lp = new LabelElementPair(g, labelNode, elementNode, labelOpNode.Type); r.alt[1].labelDefs.Map(labelNode.Text, lp); } // copy to rule from walker r.leftRecursiveRuleRefLabels = leftRecursiveRuleWalker.leftRecursiveRuleRefLabels; tool.Log("grammar", "added: " + t.ToStringTree()); return(true); }