Package org.antlr.v4.semantics

Class SymbolChecks

  • public class SymbolChecks
extends java.lang.Object
    Check for symbol problems; no side-effects. Inefficient to walk rules and such multiple times, but I like isolating all error checking outside of code that actually defines symbols etc... Side-effect: strip away redef'd rules.

    • Field Detail

      • nameToRuleMap

        java.util.Map<java.lang.String,​Rule> nameToRuleMap

      • tokenIDs

        java.util.Set<java.lang.String> tokenIDs

      • actionScopeToActionNames

        java.util.Map<java.lang.String,​java.util.Set<java.lang.String>> actionScopeToActionNames

      • reservedNames

        protected final java.util.Set<java.lang.String> reservedNames

    • Method Detail

      • process

        public void process()

      • checkActionRedefinitions

        public void checkActionRedefinitions​(java.util.List<GrammarAST> actions)

      • checkForLabelConflicts

        public void checkForLabelConflicts​(java.util.Collection<Rule> rules)
        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.

      • findAltLabelName

        private java.lang.String findAltLabelName​(org.antlr.runtime.tree.CommonTree label)

      • checkForLabelConflict

        public void checkForLabelConflict​(Rule r,
                                  GrammarAST labelID)

      • checkForAttributeConflicts

        public void checkForAttributeConflicts​(Rule r)

      • checkDeclarationRuleConflicts

        protected void checkDeclarationRuleConflicts​(Rule r,
                                             AttributeDict attributes,
                                             java.util.Set<java.lang.String> ruleNames,
                                             ErrorType errorType)

      • checkReservedNames

        protected void checkReservedNames​(java.util.Collection<Rule> rules)

      • checkForModeConflicts

        public void checkForModeConflicts​(Grammar g)

      • checkForUnreachableTokens

        public void checkForUnreachableTokens​(Grammar g)
        Algorithm steps: 1. Collect all simple string literals (i.e. 'asdf', 'as' 'df', but not [a-z]+, 'a'..'z') for all lexer rules in each mode except of autogenerated tokens (getSingleTokenValues) 2. Compare every string literal with each other (checkForOverlap) and throw TOKEN_UNREACHABLE warning if the same string found. Complexity: O(m * n^2 / 2), approximately equals to O(n^2) where m - number of modes, n - average number of lexer rules per mode. See also testUnreachableTokens unit test for details.

      • getSingleTokenValues

        private java.util.List<java.lang.String> getSingleTokenValues​(Rule rule)
        {@return} list of simple string literals for rule {@param rule}

      • checkForOverlap

        private void checkForOverlap​(Grammar g,
                             Rule rule1,
                             Rule rule2,
                             java.util.List<java.lang.String> firstTokenStringValues,
                             java.util.List<java.lang.String> secondTokenStringValues)
        For same rule compare values from next index: TOKEN_WITH_SAME_VALUES: 'asdf' | 'asdf'; For different rules compare from start value: TOKEN1: 'asdf'; TOKEN2: 'asdf';

      • checkRuleArgs

        public void checkRuleArgs​(Grammar g,
                          java.util.List<GrammarAST> rulerefs)

      • checkForQualifiedRuleIssues

        public void checkForQualifiedRuleIssues​(Grammar g,
                                        java.util.List<GrammarAST> qualifiedRuleRefs)