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

Example 16 with LeftRecursiveRule

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

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 {
                // Suppressed since this build has secondary support for left recursive rules that don't
                // match the patterns for precedence rules.
                // 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, new GrammarASTAdaptor().create(ANTLRParser.INT, "0"));
        }
    }
}

Example 17 with LeftRecursiveRule

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

the class ParserATNFactory method createATN.

@NotNull
@Override
public ATN createATN() {
    _createATN(g.rules.values());
    assert atn.maxTokenType == g.getMaxTokenType();
    addRuleFollowLinks();
    addEOFTransitionToStartRules();
    ATNOptimizer.optimize(g, atn);
    for (Tuple3<? extends Rule, ? extends ATNState, ? extends ATNState> pair : preventEpsilonClosureBlocks) {
        LL1Analyzer analyzer = new LL1Analyzer(atn);
        ATNState blkStart = pair.getItem2();
        ATNState blkStop = pair.getItem3();
        IntervalSet lookahead = analyzer.LOOK(blkStart, blkStop, PredictionContext.EMPTY_LOCAL);
        if (lookahead.contains(org.antlr.v4.runtime.Token.EPSILON)) {
            ErrorType errorType = pair.getItem1() instanceof LeftRecursiveRule ? ErrorType.EPSILON_LR_FOLLOW : ErrorType.EPSILON_CLOSURE;
            g.tool.errMgr.grammarError(errorType, g.fileName, ((GrammarAST) pair.getItem1().ast.getChild(0)).getToken(), pair.getItem1().name);
        }
    }
    optionalCheck: for (Tuple3<? extends Rule, ? extends ATNState, ? extends ATNState> pair : preventEpsilonOptionalBlocks) {
        int bypassCount = 0;
        for (int i = 0; i < pair.getItem2().getNumberOfTransitions(); i++) {
            ATNState startState = pair.getItem2().transition(i).target;
            if (startState == pair.getItem3()) {
                bypassCount++;
                continue;
            }
            LL1Analyzer analyzer = new LL1Analyzer(atn);
            if (analyzer.LOOK(startState, pair.getItem3(), PredictionContext.EMPTY_LOCAL).contains(org.antlr.v4.runtime.Token.EPSILON)) {
                g.tool.errMgr.grammarError(ErrorType.EPSILON_OPTIONAL, g.fileName, ((GrammarAST) pair.getItem1().ast.getChild(0)).getToken(), pair.getItem1().name);
                continue optionalCheck;
            }
        }
        if (bypassCount != 1) {
            throw new UnsupportedOperationException("Expected optional block with exactly 1 bypass alternative.");
        }
    }
    return atn;
}

Example 18 with LeftRecursiveRule

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

the class TestATNParserPrediction method testAltsForLRRuleComputation3.

@Test
public void testAltsForLRRuleComputation3() throws Exception {
    Grammar g = new Grammar("grammar T;\n" + // should have no effect
    "random : 'blort';\n" + "e : '--' e\n" + "  | e '*' e\n" + "  | e '+' e\n" + "  | e '--'\n" + "  | ID\n" + "  ;\n" + "ID : [a-z]+ ;\n" + "INT : [0-9]+ ;\n" + "WS : [ \\r\\t\\n]+ ;");
    Rule e = g.getRule("e");
    assertTrue(e instanceof LeftRecursiveRule);
    LeftRecursiveRule lr = (LeftRecursiveRule) e;
    assertEquals("[0, 1, 5]", Arrays.toString(lr.getPrimaryAlts()));
    assertEquals("[0, 2, 3, 4]", Arrays.toString(lr.getRecursiveOpAlts()));
}

Example 19 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;
    }
}

Example 20 with LeftRecursiveRule

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

the class OutputModelController method buildLeftRecursiveRuleFunction.

public void buildLeftRecursiveRuleFunction(LeftRecursiveRule r, LeftRecursiveRuleFunction function) {
    buildNormalRuleFunction(r, function);
    // now inject code to start alts
    CodeGenerator gen = delegate.getGenerator();
    STGroup codegenTemplates = gen.getTemplates();
    // pick out alt(s) for primaries
    CodeBlockForOuterMostAlt outerAlt = (CodeBlockForOuterMostAlt) function.code.get(0);
    List<CodeBlockForAlt> primaryAltsCode = new ArrayList<CodeBlockForAlt>();
    SrcOp primaryStuff = outerAlt.ops.get(0);
    if (primaryStuff instanceof Choice) {
        Choice primaryAltBlock = (Choice) primaryStuff;
        primaryAltsCode.addAll(primaryAltBlock.alts);
    } else {
        // just a single alt I guess; no block
        primaryAltsCode.add((CodeBlockForAlt) primaryStuff);
    }
    // pick out alt(s) for op alts
    StarBlock opAltStarBlock = (StarBlock) outerAlt.ops.get(1);
    CodeBlockForAlt altForOpAltBlock = opAltStarBlock.alts.get(0);
    List<CodeBlockForAlt> opAltsCode = new ArrayList<CodeBlockForAlt>();
    SrcOp opStuff = altForOpAltBlock.ops.get(0);
    if (opStuff instanceof AltBlock) {
        AltBlock opAltBlock = (AltBlock) opStuff;
        opAltsCode.addAll(opAltBlock.alts);
    } else {
        // just a single alt I guess; no block
        opAltsCode.add((CodeBlockForAlt) opStuff);
    }
    // Insert code in front of each primary alt to create specialized ctx if there was a label
    for (int i = 0; i < primaryAltsCode.size(); i++) {
        LeftRecursiveRuleAltInfo altInfo = r.recPrimaryAlts.get(i);
        if (altInfo.altLabel == null)
            continue;
        ST altActionST = codegenTemplates.getInstanceOf("recRuleReplaceContext");
        altActionST.add("ctxName", Utils.capitalize(altInfo.altLabel));
        Action altAction = new Action(delegate, function.altLabelCtxs.get(altInfo.altLabel), altActionST);
        CodeBlockForAlt alt = primaryAltsCode.get(i);
        alt.insertOp(0, altAction);
    }
    // Insert code to set ctx.stop after primary block and before op * loop
    ST setStopTokenAST = codegenTemplates.getInstanceOf("recRuleSetStopToken");
    Action setStopTokenAction = new Action(delegate, function.ruleCtx, setStopTokenAST);
    outerAlt.insertOp(1, setStopTokenAction);
    // Insert code to set _prevctx at start of * loop
    ST setPrevCtx = codegenTemplates.getInstanceOf("recRuleSetPrevCtx");
    Action setPrevCtxAction = new Action(delegate, function.ruleCtx, setPrevCtx);
    opAltStarBlock.addIterationOp(setPrevCtxAction);
    // Insert code in front of each op alt to create specialized ctx if there was an alt label
    for (int i = 0; i < opAltsCode.size(); i++) {
        ST altActionST;
        LeftRecursiveRuleAltInfo altInfo = r.recOpAlts.getElement(i);
        String templateName;
        if (altInfo.altLabel != null) {
            templateName = "recRuleLabeledAltStartAction";
            altActionST = codegenTemplates.getInstanceOf(templateName);
            altActionST.add("currentAltLabel", altInfo.altLabel);
        } else {
            templateName = "recRuleAltStartAction";
            altActionST = codegenTemplates.getInstanceOf(templateName);
            altActionST.add("ctxName", Utils.capitalize(r.name));
        }
        altActionST.add("ruleName", r.name);
        // add label of any lr ref we deleted
        altActionST.add("label", altInfo.leftRecursiveRuleRefLabel);
        if (altActionST.impl.formalArguments.containsKey("isListLabel")) {
            altActionST.add("isListLabel", altInfo.isListLabel);
        } else if (altInfo.isListLabel) {
            delegate.getGenerator().tool.errMgr.toolError(ErrorType.CODE_TEMPLATE_ARG_ISSUE, templateName, "isListLabel");
        }
        Action altAction = new Action(delegate, function.altLabelCtxs.get(altInfo.altLabel), altActionST);
        CodeBlockForAlt alt = opAltsCode.get(i);
        alt.insertOp(0, altAction);
    }
}