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

Example 16 with Alternative

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

the class SymbolChecks method checkForLabelConflicts.

/** Make sure a label doesn't conflict with another symbol.
     *  Labels must not conflict with: rules, tokens, scope names,
     *  return values, parameters, and rule-scope dynamic attributes
     *  defined in surrounding rule.  Also they must have same type
     *  for repeated defs.
     */
public void checkForLabelConflicts(Collection<Rule> rules) {
    for (Rule r : rules) {
        checkForAttributeConflicts(r);
        Map<String, LabelElementPair> labelNameSpace = new HashMap<>();
        for (int i = 1; i <= r.numberOfAlts; i++) {
            Alternative a = r.alt[i];
            for (List<LabelElementPair> pairs : a.labelDefs.values()) {
                if (r.hasAltSpecificContexts()) {
                    // Collect labelName-labeledRules map for rule with alternative labels.
                    Map<String, List<LabelElementPair>> labelPairs = new HashMap<>();
                    for (LabelElementPair p : pairs) {
                        String labelName = findAltLabelName(p.label);
                        if (labelName != null) {
                            List<LabelElementPair> list;
                            if (labelPairs.containsKey(labelName)) {
                                list = labelPairs.get(labelName);
                            } else {
                                list = new ArrayList<>();
                                labelPairs.put(labelName, list);
                            }
                            list.add(p);
                        }
                    }
                    for (List<LabelElementPair> internalPairs : labelPairs.values()) {
                        labelNameSpace.clear();
                        checkLabelPairs(r, labelNameSpace, internalPairs);
                    }
                } else {
                    checkLabelPairs(r, labelNameSpace, pairs);
                }
            }
        }
    }
}

Example 17 with Alternative

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

the class ParserATNFactory method epsilon.

/** From an empty alternative build {@code o-e->o}. */
@Override
public Handle epsilon(GrammarAST node) {
    ATNState left = newState(node);
    ATNState right = newState(node);
    epsilon(left, right);
    node.atnState = left;
    return new Handle(left, right);
}