chevrotain
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Chevrotain is a high performance fault tolerant javascript parsing DSL for building recursive decent parsers
186 lines • 10.3 kB
JavaScript
import { hasTokenLabel, tokenLabel } from "../scan/tokens_public";
import * as utils from "../utils/utils";
import { first, map, reduce } from "../utils/utils";
import { NonTerminal, Rule, Terminal } from "./grammar/gast/gast_public";
import { getProductionDslName } from "./grammar/gast/gast";
export var defaultParserErrorProvider = {
buildMismatchTokenMessage: function (_a) {
var expected = _a.expected, actual = _a.actual, previous = _a.previous, ruleName = _a.ruleName;
var hasLabel = hasTokenLabel(expected);
var expectedMsg = hasLabel
? "--> " + tokenLabel(expected) + " <--"
: "token of type --> " + expected.name + " <--";
var msg = "Expecting " + expectedMsg + " but found --> '" + actual.image + "' <--";
return msg;
},
buildNotAllInputParsedMessage: function (_a) {
var firstRedundant = _a.firstRedundant, ruleName = _a.ruleName;
return "Redundant input, expecting EOF but found: " + firstRedundant.image;
},
buildNoViableAltMessage: function (_a) {
var expectedPathsPerAlt = _a.expectedPathsPerAlt, actual = _a.actual, previous = _a.previous, customUserDescription = _a.customUserDescription, ruleName = _a.ruleName;
var errPrefix = "Expecting: ";
// TODO: issue: No Viable Alternative Error may have incomplete details. #502
var actualText = first(actual).image;
var errSuffix = "\nbut found: '" + actualText + "'";
if (customUserDescription) {
return errPrefix + customUserDescription + errSuffix;
}
else {
var allLookAheadPaths = reduce(expectedPathsPerAlt, function (result, currAltPaths) { return result.concat(currAltPaths); }, []);
var nextValidTokenSequences = map(allLookAheadPaths, function (currPath) {
return "[" + map(currPath, function (currTokenType) { return tokenLabel(currTokenType); }).join(", ") + "]";
});
var nextValidSequenceItems = map(nextValidTokenSequences, function (itemMsg, idx) { return " " + (idx + 1) + ". " + itemMsg; });
var calculatedDescription = "one of these possible Token sequences:\n" + nextValidSequenceItems.join("\n");
return errPrefix + calculatedDescription + errSuffix;
}
},
buildEarlyExitMessage: function (_a) {
var expectedIterationPaths = _a.expectedIterationPaths, actual = _a.actual, customUserDescription = _a.customUserDescription, ruleName = _a.ruleName;
var errPrefix = "Expecting: ";
// TODO: issue: No Viable Alternative Error may have incomplete details. #502
var actualText = first(actual).image;
var errSuffix = "\nbut found: '" + actualText + "'";
if (customUserDescription) {
return errPrefix + customUserDescription + errSuffix;
}
else {
var nextValidTokenSequences = map(expectedIterationPaths, function (currPath) {
return "[" + map(currPath, function (currTokenType) { return tokenLabel(currTokenType); }).join(",") + "]";
});
var calculatedDescription = "expecting at least one iteration which starts with one of these possible Token sequences::\n " +
("<" + nextValidTokenSequences.join(" ,") + ">");
return errPrefix + calculatedDescription + errSuffix;
}
}
};
Object.freeze(defaultParserErrorProvider);
export var defaultGrammarResolverErrorProvider = {
buildRuleNotFoundError: function (topLevelRule, undefinedRule) {
var msg = "Invalid grammar, reference to a rule which is not defined: ->" +
undefinedRule.nonTerminalName +
"<-\n" +
"inside top level rule: ->" +
topLevelRule.name +
"<-";
return msg;
}
};
export var defaultGrammarValidatorErrorProvider = {
buildDuplicateFoundError: function (topLevelRule, duplicateProds) {
function getExtraProductionArgument(prod) {
if (prod instanceof Terminal) {
return prod.terminalType.name;
}
else if (prod instanceof NonTerminal) {
return prod.nonTerminalName;
}
else {
return "";
}
}
var topLevelName = topLevelRule.name;
var duplicateProd = first(duplicateProds);
var index = duplicateProd.idx;
var dslName = getProductionDslName(duplicateProd);
var extraArgument = getExtraProductionArgument(duplicateProd);
var hasExplicitIndex = index > 0;
var msg = "->" + dslName + (hasExplicitIndex ? index : "") + "<- " + (extraArgument ? "with argument: ->" + extraArgument + "<-" : "") + "\n appears more than once (" + duplicateProds.length + " times) in the top level rule: ->" + topLevelName + "<-. \n For further details see: https://chevrotain.io/docs/FAQ.html#NUMERICAL_SUFFIXES \n ";
// white space trimming time! better to trim afterwards as it allows to use WELL formatted multi line template strings...
msg = msg.replace(/[ \t]+/g, " ");
msg = msg.replace(/\s\s+/g, "\n");
return msg;
},
buildNamespaceConflictError: function (rule) {
var errMsg = "Namespace conflict found in grammar.\n" +
("The grammar has both a Terminal(Token) and a Non-Terminal(Rule) named: <" + rule.name + ">.\n") +
"To resolve this make sure each Terminal and Non-Terminal names are unique\n" +
"This is easy to accomplish by using the convention that Terminal names start with an uppercase letter\n" +
"and Non-Terminal names start with a lower case letter.";
return errMsg;
},
buildAlternationPrefixAmbiguityError: function (options) {
var pathMsg = map(options.prefixPath, function (currTok) {
return tokenLabel(currTok);
}).join(", ");
var occurrence = options.alternation.idx === 0 ? "" : options.alternation.idx;
var errMsg = "Ambiguous alternatives: <" + options.ambiguityIndices.join(" ,") + "> due to common lookahead prefix\n" +
("in <OR" + occurrence + "> inside <" + options.topLevelRule.name + "> Rule,\n") +
("<" + pathMsg + "> may appears as a prefix path in all these alternatives.\n") +
"See: https://chevrotain.io/docs/guide/resolving_grammar_errors.html#COMMON_PREFIX\n" +
"For Further details.";
return errMsg;
},
buildAlternationAmbiguityError: function (options) {
var pathMsg = map(options.prefixPath, function (currtok) {
return tokenLabel(currtok);
}).join(", ");
var occurrence = options.alternation.idx === 0 ? "" : options.alternation.idx;
var currMessage = "Ambiguous Alternatives Detected: <" + options.ambiguityIndices.join(" ,") + "> in <OR" + occurrence + ">" +
(" inside <" + options.topLevelRule.name + "> Rule,\n") +
("<" + pathMsg + "> may appears as a prefix path in all these alternatives.\n");
currMessage =
currMessage +
"See: https://chevrotain.io/docs/guide/resolving_grammar_errors.html#AMBIGUOUS_ALTERNATIVES\n" +
"For Further details.";
return currMessage;
},
buildEmptyRepetitionError: function (options) {
var dslName = getProductionDslName(options.repetition);
if (options.repetition.idx !== 0) {
dslName += options.repetition.idx;
}
var errMsg = "The repetition <" + dslName + "> within Rule <" + options.topLevelRule.name + "> can never consume any tokens.\n" +
"This could lead to an infinite loop.";
return errMsg;
},
// TODO: remove - `errors_public` from nyc.config.js exclude
// once this method is fully removed from this file
buildTokenNameError: function (options) {
/* istanbul ignore next */
return "deprecated";
},
buildEmptyAlternationError: function (options) {
var errMsg = "Ambiguous empty alternative: <" + (options.emptyChoiceIdx + 1) + ">" +
(" in <OR" + options.alternation.idx + "> inside <" + options.topLevelRule.name + "> Rule.\n") +
"Only the last alternative may be an empty alternative.";
return errMsg;
},
buildTooManyAlternativesError: function (options) {
var errMsg = "An Alternation cannot have more than 256 alternatives:\n" +
("<OR" + options.alternation.idx + "> inside <" + options.topLevelRule.name + "> Rule.\n has " + (options.alternation.definition.length + 1) + " alternatives.");
return errMsg;
},
buildLeftRecursionError: function (options) {
var ruleName = options.topLevelRule.name;
var pathNames = utils.map(options.leftRecursionPath, function (currRule) { return currRule.name; });
var leftRecursivePath = ruleName + " --> " + pathNames
.concat([ruleName])
.join(" --> ");
var errMsg = "Left Recursion found in grammar.\n" +
("rule: <" + ruleName + "> can be invoked from itself (directly or indirectly)\n") +
("without consuming any Tokens. The grammar path that causes this is: \n " + leftRecursivePath + "\n") +
" To fix this refactor your grammar to remove the left recursion.\n" +
"see: https://en.wikipedia.org/wiki/LL_parser#Left_Factoring.";
return errMsg;
},
// TODO: remove - `errors_public` from nyc.config.js exclude
// once this method is fully removed from this file
buildInvalidRuleNameError: function (options) {
/* istanbul ignore next */
return "deprecated";
},
buildDuplicateRuleNameError: function (options) {
var ruleName;
if (options.topLevelRule instanceof Rule) {
ruleName = options.topLevelRule.name;
}
else {
ruleName = options.topLevelRule;
}
var errMsg = "Duplicate definition, rule: ->" + ruleName + "<- is already defined in the grammar: ->" + options.grammarName + "<-";
return errMsg;
}
};
//# sourceMappingURL=errors_public.js.map