Examples with LeftRecursiveRule org.antlr.v4.tool.LeftRecursiveRule used on opensource projects

Example 6 with LeftRecursiveRule

use of org.antlr.v4.tool.LeftRecursiveRule in project antlr4 by antlr.

the class ParserATNFactory method createRuleStartAndStopATNStates.

/** Define all the rule begin/end ATNStates to solve forward reference
	 *  issues.
	 */
void createRuleStartAndStopATNStates() {
    atn.ruleToStartState = new RuleStartState[g.rules.size()];
    atn.ruleToStopState = new RuleStopState[g.rules.size()];
    for (Rule r : g.rules.values()) {
        RuleStartState start = newState(RuleStartState.class, r.ast);
        RuleStopState stop = newState(RuleStopState.class, r.ast);
        start.stopState = stop;
        start.isLeftRecursiveRule = r instanceof LeftRecursiveRule;
        start.setRuleIndex(r.index);
        stop.setRuleIndex(r.index);
        atn.ruleToStartState[r.index] = start;
        atn.ruleToStopState[r.index] = stop;
    }
}

Example 7 with LeftRecursiveRule

use of org.antlr.v4.tool.LeftRecursiveRule in project antlr4 by antlr.

the class LeftRecursiveRuleTransformer method translateLeftRecursiveRules.

public void translateLeftRecursiveRules() {
    String language = g.getOptionString("language");
    // translate all recursive rules
    List<String> leftRecursiveRuleNames = new ArrayList<String>();
    for (Rule r : rules) {
        if (!Grammar.isTokenName(r.name)) {
            if (LeftRecursiveRuleAnalyzer.hasImmediateRecursiveRuleRefs(r.ast, r.name)) {
                boolean fitsPattern = translateLeftRecursiveRule(ast, (LeftRecursiveRule) r, language);
                if (fitsPattern) {
                    leftRecursiveRuleNames.add(r.name);
                } else {
                    // better given an error that non-conforming left-recursion exists
                    tool.errMgr.grammarError(ErrorType.NONCONFORMING_LR_RULE, g.fileName, ((GrammarAST) r.ast.getChild(0)).token, r.name);
                }
            }
        }
    }
    // update all refs to recursive rules to have [0] argument
    for (GrammarAST r : ast.getNodesWithType(ANTLRParser.RULE_REF)) {
        // must be rule def
        if (r.getParent().getType() == ANTLRParser.RULE)
            continue;
        // already has arg; must be in rewritten rule
        if (((GrammarASTWithOptions) r).getOptionString(PRECEDENCE_OPTION_NAME) != null)
            continue;
        if (leftRecursiveRuleNames.contains(r.getText())) {
            // found ref to recursive rule not already rewritten with arg
            ((GrammarASTWithOptions) r).setOption(PRECEDENCE_OPTION_NAME, (GrammarAST) new GrammarASTAdaptor().create(ANTLRParser.INT, "0"));
        }
    }
}

Example 8 with LeftRecursiveRule

use of org.antlr.v4.tool.LeftRecursiveRule in project antlr4 by antlr.

the class LeftRecursiveRuleTransformer method setAltASTPointers.

/**
	 * <pre>
	 * (RULE e int _p (returns int v)
	 * 	(BLOCK
	 * 	  (ALT
	 * 		(BLOCK
	 * 			(ALT INT {$v = $INT.int;})
	 * 			(ALT '(' (= x e) ')' {$v = $x.v;})
	 * 			(ALT ID))
	 * 		(* (BLOCK
	 *			(OPTIONS ...)
	 * 			(ALT {7 &gt;= $_p}? '*' (= b e) {$v = $a.v * $b.v;})
	 * 			(ALT {6 &gt;= $_p}? '+' (= b e) {$v = $a.v + $b.v;})
	 * 			(ALT {3 &gt;= $_p}? '++') (ALT {2 &gt;= $_p}? '--'))))))
	 * </pre>
	 */
public void setAltASTPointers(LeftRecursiveRule r, RuleAST t) {
    //		System.out.println("RULE: "+t.toStringTree());
    BlockAST ruleBlk = (BlockAST) t.getFirstChildWithType(ANTLRParser.BLOCK);
    AltAST mainAlt = (AltAST) ruleBlk.getChild(0);
    BlockAST primaryBlk = (BlockAST) mainAlt.getChild(0);
    // (* BLOCK ...)
    BlockAST opsBlk = (BlockAST) mainAlt.getChild(1).getChild(0);
    for (int i = 0; i < r.recPrimaryAlts.size(); i++) {
        LeftRecursiveRuleAltInfo altInfo = r.recPrimaryAlts.get(i);
        altInfo.altAST = (AltAST) primaryBlk.getChild(i);
        altInfo.altAST.leftRecursiveAltInfo = altInfo;
        altInfo.originalAltAST.leftRecursiveAltInfo = altInfo;
    //			altInfo.originalAltAST.parent = altInfo.altAST.parent;
    //			System.out.println(altInfo.altAST.toStringTree());
    }
    for (int i = 0; i < r.recOpAlts.size(); i++) {
        LeftRecursiveRuleAltInfo altInfo = r.recOpAlts.getElement(i);
        altInfo.altAST = (AltAST) opsBlk.getChild(i);
        altInfo.altAST.leftRecursiveAltInfo = altInfo;
        altInfo.originalAltAST.leftRecursiveAltInfo = altInfo;
    //			altInfo.originalAltAST.parent = altInfo.altAST.parent;
    //			System.out.println(altInfo.altAST.toStringTree());
    }
}

Example 9 with LeftRecursiveRule

use of org.antlr.v4.tool.LeftRecursiveRule in project antlr4 by antlr.

the class LeftRecursiveRuleTransformer method translateLeftRecursiveRule.

/** Return true if successful */
public boolean translateLeftRecursiveRule(GrammarRootAST ast, LeftRecursiveRule r, String language) {
    //tool.log("grammar", ruleAST.toStringTree());
    GrammarAST prevRuleAST = r.ast;
    String ruleName = prevRuleAST.getChild(0).getText();
    LeftRecursiveRuleAnalyzer leftRecursiveRuleWalker = new LeftRecursiveRuleAnalyzer(prevRuleAST, tool, ruleName, language);
    boolean isLeftRec;
    try {
        //			System.out.println("TESTING ---------------\n"+
        //							   leftRecursiveRuleWalker.text(ruleAST));
        isLeftRec = leftRecursiveRuleWalker.rec_rule();
    } catch (RecognitionException re) {
        // didn't match; oh well
        isLeftRec = false;
    }
    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.out.println("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)).getToken();
    // update grammar AST and set rule's AST.
    RULES.setChild(prevRuleAST.getChildIndex(), 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 ArrayList<LeftRecursiveRuleAltInfo>();
    r.recPrimaryAlts.addAll(leftRecursiveRuleWalker.prefixAndOtherAlts);
    if (r.recPrimaryAlts.isEmpty()) {
        tool.errMgr.grammarError(ErrorType.NO_NON_LR_ALTS, g.fileName, ((GrammarAST) r.ast.getChild(0)).getToken(), r.name);
    }
    r.recOpAlts = new OrderedHashMap<Integer, LeftRecursiveRuleAltInfo>();
    r.recOpAlts.putAll(leftRecursiveRuleWalker.binaryAlts);
    r.recOpAlts.putAll(leftRecursiveRuleWalker.ternaryAlts);
    r.recOpAlts.putAll(leftRecursiveRuleWalker.suffixAlts);
    // 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.getText(), g);
        r.args.type = AttributeDict.DictType.ARG;
        r.args.ast = arg;
        // todo: isn't this Rule or something?
        arg.resolver = r.alt[1];
    }
    // these are so $label in action translation works
    for (Pair<GrammarAST, String> pair : leftRecursiveRuleWalker.leftRecursiveRuleRefLabels) {
        GrammarAST labelNode = pair.a;
        GrammarAST labelOpNode = (GrammarAST) labelNode.getParent();
        GrammarAST elementNode = (GrammarAST) labelOpNode.getChild(1);
        LabelElementPair lp = new LabelElementPair(g, labelNode, elementNode, labelOpNode.getType());
        r.alt[1].labelDefs.map(labelNode.getText(), lp);
    }
    // copy to rule from walker
    r.leftRecursiveRuleRefLabels = leftRecursiveRuleWalker.leftRecursiveRuleRefLabels;
    tool.log("grammar", "added: " + t.toStringTree());
    return true;
}

Example 10 with LeftRecursiveRule

use of org.antlr.v4.tool.LeftRecursiveRule in project antlr4 by antlr.

the class RuleCollector method discoverRule.

@Override
public void discoverRule(RuleAST rule, GrammarAST ID, List<GrammarAST> modifiers, ActionAST arg, ActionAST returns, GrammarAST thrws, GrammarAST options, ActionAST locals, List<GrammarAST> actions, GrammarAST block) {
    int numAlts = block.getChildCount();
    Rule r;
    if (LeftRecursiveRuleAnalyzer.hasImmediateRecursiveRuleRefs(rule, ID.getText())) {
        r = new LeftRecursiveRule(g, ID.getText(), rule);
    } else {
        r = new Rule(g, ID.getText(), rule, numAlts);
    }
    rules.put(r.name, r);
    if (arg != null) {
        r.args = ScopeParser.parseTypedArgList(arg, arg.getText(), 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.getText(), g);
        r.retvals.type = AttributeDict.DictType.RET;
        r.retvals.ast = returns;
    }
    if (locals != null) {
        r.locals = ScopeParser.parseTypedArgList(locals, locals.getText(), g);
        r.locals.type = AttributeDict.DictType.LOCAL;
        r.locals.ast = locals;
    }
    for (GrammarAST a : actions) {
        // a = ^(AT ID ACTION)
        ActionAST action = (ActionAST) a.getChild(1);
        r.namedActions.put(a.getChild(0).getText(), action);
        action.resolver = r;
    }
}