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

Example 1 with LeftRecursiveRule

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

the class TestATNParserPrediction method testAltsForLRRuleComputation.

@Test
public void testAltsForLRRuleComputation() throws Exception {
    Grammar g = new Grammar("grammar T;\n" + "e : e '*' e\n" + "  | INT\n" + "  | e '+' 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, 2, 4]", Arrays.toString(lr.getPrimaryAlts()));
    assertEquals("[0, 1, 3]", Arrays.toString(lr.getRecursiveOpAlts()));
}

Example 2 with LeftRecursiveRule

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

the class TestATNParserPrediction method testAltsForLRRuleComputation2.

@Test
public void testAltsForLRRuleComputation2() throws Exception {
    Grammar g = new Grammar("grammar T;\n" + "e : INT\n" + "  | e '*' 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, 3]", Arrays.toString(lr.getPrimaryAlts()));
    assertEquals("[0, 2]", Arrays.toString(lr.getRecursiveOpAlts()));
}

Example 3 with LeftRecursiveRule

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

the class Grammar method getStateToGrammarRegionMap.

public static Map<Integer, Interval> getStateToGrammarRegionMap(GrammarRootAST ast, IntervalSet grammarTokenTypes) {
    Map<Integer, Interval> stateToGrammarRegionMap = new HashMap<Integer, Interval>();
    if (ast == null)
        return stateToGrammarRegionMap;
    List<GrammarAST> nodes = ast.getNodesWithType(grammarTokenTypes);
    for (GrammarAST n : nodes) {
        if (n.atnState != null) {
            Interval tokenRegion = Interval.of(n.getTokenStartIndex(), n.getTokenStopIndex());
            org.antlr.runtime.tree.Tree ruleNode = null;
            // RULEs, BLOCKs of transformed recursive rules point to original token interval
            switch(n.getType()) {
                case ANTLRParser.RULE:
                    ruleNode = n;
                    break;
                case ANTLRParser.BLOCK:
                case ANTLRParser.CLOSURE:
                    ruleNode = n.getAncestor(ANTLRParser.RULE);
                    break;
            }
            if (ruleNode instanceof RuleAST) {
                String ruleName = ((RuleAST) ruleNode).getRuleName();
                Rule r = ast.g.getRule(ruleName);
                if (r instanceof LeftRecursiveRule) {
                    RuleAST originalAST = ((LeftRecursiveRule) r).getOriginalAST();
                    tokenRegion = Interval.of(originalAST.getTokenStartIndex(), originalAST.getTokenStopIndex());
                }
            }
            stateToGrammarRegionMap.put(n.atnState.stateNumber, tokenRegion);
        }
    }
    return stateToGrammarRegionMap;
}

Example 4 with LeftRecursiveRule

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

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 (Tuple2<GrammarAST, String> pair : leftRecursiveRuleWalker.leftRecursiveRuleRefLabels) {
        GrammarAST labelNode = pair.getItem1();
        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 5 with LeftRecursiveRule

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

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.isPrecedenceRule = r instanceof LeftRecursiveRule;
        start.setRuleIndex(r.index);
        stop.setRuleIndex(r.index);
        atn.ruleToStartState[r.index] = start;
        atn.ruleToStopState[r.index] = stop;
    }
}