chevrotain
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Chevrotain is a high performance fault tolerant javascript parsing DSL for building recursive decent parsers
499 lines • 23.7 kB
JavaScript
;
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
exports.areTokenCategoriesNotUsed = exports.isStrictPrefixOfPath = exports.containsPath = exports.getLookaheadPathsForOptionalProd = exports.getLookaheadPathsForOr = exports.lookAheadSequenceFromAlternatives = exports.buildSingleAlternativeLookaheadFunction = exports.buildAlternativesLookAheadFunc = exports.buildLookaheadFuncForOptionalProd = exports.buildLookaheadFuncForOr = exports.getProdType = exports.PROD_TYPE = void 0;
var utils_1 = require("../../utils/utils");
var interpreter_1 = require("./interpreter");
var rest_1 = require("./rest");
var tokens_1 = require("../../scan/tokens");
var gast_public_1 = require("./gast/gast_public");
var gast_visitor_public_1 = require("./gast/gast_visitor_public");
var PROD_TYPE;
(function (PROD_TYPE) {
PROD_TYPE[PROD_TYPE["OPTION"] = 0] = "OPTION";
PROD_TYPE[PROD_TYPE["REPETITION"] = 1] = "REPETITION";
PROD_TYPE[PROD_TYPE["REPETITION_MANDATORY"] = 2] = "REPETITION_MANDATORY";
PROD_TYPE[PROD_TYPE["REPETITION_MANDATORY_WITH_SEPARATOR"] = 3] = "REPETITION_MANDATORY_WITH_SEPARATOR";
PROD_TYPE[PROD_TYPE["REPETITION_WITH_SEPARATOR"] = 4] = "REPETITION_WITH_SEPARATOR";
PROD_TYPE[PROD_TYPE["ALTERNATION"] = 5] = "ALTERNATION";
})(PROD_TYPE = exports.PROD_TYPE || (exports.PROD_TYPE = {}));
function getProdType(prod) {
/* istanbul ignore else */
if (prod instanceof gast_public_1.Option) {
return PROD_TYPE.OPTION;
}
else if (prod instanceof gast_public_1.Repetition) {
return PROD_TYPE.REPETITION;
}
else if (prod instanceof gast_public_1.RepetitionMandatory) {
return PROD_TYPE.REPETITION_MANDATORY;
}
else if (prod instanceof gast_public_1.RepetitionMandatoryWithSeparator) {
return PROD_TYPE.REPETITION_MANDATORY_WITH_SEPARATOR;
}
else if (prod instanceof gast_public_1.RepetitionWithSeparator) {
return PROD_TYPE.REPETITION_WITH_SEPARATOR;
}
else if (prod instanceof gast_public_1.Alternation) {
return PROD_TYPE.ALTERNATION;
}
else {
throw Error("non exhaustive match");
}
}
exports.getProdType = getProdType;
function buildLookaheadFuncForOr(occurrence, ruleGrammar, maxLookahead, hasPredicates, dynamicTokensEnabled, laFuncBuilder) {
var lookAheadPaths = getLookaheadPathsForOr(occurrence, ruleGrammar, maxLookahead);
var tokenMatcher = areTokenCategoriesNotUsed(lookAheadPaths)
? tokens_1.tokenStructuredMatcherNoCategories
: tokens_1.tokenStructuredMatcher;
return laFuncBuilder(lookAheadPaths, hasPredicates, tokenMatcher, dynamicTokensEnabled);
}
exports.buildLookaheadFuncForOr = buildLookaheadFuncForOr;
/**
* When dealing with an Optional production (OPTION/MANY/2nd iteration of AT_LEAST_ONE/...) we need to compare
* the lookahead "inside" the production and the lookahead immediately "after" it in the same top level rule (context free).
*
* Example: given a production:
* ABC(DE)?DF
*
* The optional '(DE)?' should only be entered if we see 'DE'. a single Token 'D' is not sufficient to distinguish between the two
* alternatives.
*
* @returns A Lookahead function which will return true IFF the parser should parse the Optional production.
*/
function buildLookaheadFuncForOptionalProd(occurrence, ruleGrammar, k, dynamicTokensEnabled, prodType, lookaheadBuilder) {
var lookAheadPaths = getLookaheadPathsForOptionalProd(occurrence, ruleGrammar, prodType, k);
var tokenMatcher = areTokenCategoriesNotUsed(lookAheadPaths)
? tokens_1.tokenStructuredMatcherNoCategories
: tokens_1.tokenStructuredMatcher;
return lookaheadBuilder(lookAheadPaths[0], tokenMatcher, dynamicTokensEnabled);
}
exports.buildLookaheadFuncForOptionalProd = buildLookaheadFuncForOptionalProd;
function buildAlternativesLookAheadFunc(alts, hasPredicates, tokenMatcher, dynamicTokensEnabled) {
var numOfAlts = alts.length;
var areAllOneTokenLookahead = utils_1.every(alts, function (currAlt) {
return utils_1.every(currAlt, function (currPath) {
return currPath.length === 1;
});
});
// This version takes into account the predicates as well.
if (hasPredicates) {
/**
* @returns {number} - The chosen alternative index
*/
return function (orAlts) {
// unfortunately the predicates must be extracted every single time
// as they cannot be cached due to references to parameters(vars) which are no longer valid.
// note that in the common case of no predicates, no cpu time will be wasted on this (see else block)
var predicates = utils_1.map(orAlts, function (currAlt) { return currAlt.GATE; });
for (var t = 0; t < numOfAlts; t++) {
var currAlt = alts[t];
var currNumOfPaths = currAlt.length;
var currPredicate = predicates[t];
if (currPredicate !== undefined && currPredicate.call(this) === false) {
// if the predicate does not match there is no point in checking the paths
continue;
}
nextPath: for (var j = 0; j < currNumOfPaths; j++) {
var currPath = currAlt[j];
var currPathLength = currPath.length;
for (var i = 0; i < currPathLength; i++) {
var nextToken = this.LA(i + 1);
if (tokenMatcher(nextToken, currPath[i]) === false) {
// mismatch in current path
// try the next pth
continue nextPath;
}
}
// found a full path that matches.
// this will also work for an empty ALT as the loop will be skipped
return t;
}
// none of the paths for the current alternative matched
// try the next alternative
}
// none of the alternatives could be matched
return undefined;
};
}
else if (areAllOneTokenLookahead && !dynamicTokensEnabled) {
// optimized (common) case of all the lookaheads paths requiring only
// a single token lookahead. These Optimizations cannot work if dynamically defined Tokens are used.
var singleTokenAlts = utils_1.map(alts, function (currAlt) {
return utils_1.flatten(currAlt);
});
var choiceToAlt_1 = utils_1.reduce(singleTokenAlts, function (result, currAlt, idx) {
utils_1.forEach(currAlt, function (currTokType) {
if (!utils_1.has(result, currTokType.tokenTypeIdx)) {
result[currTokType.tokenTypeIdx] = idx;
}
utils_1.forEach(currTokType.categoryMatches, function (currExtendingType) {
if (!utils_1.has(result, currExtendingType)) {
result[currExtendingType] = idx;
}
});
});
return result;
}, []);
/**
* @returns {number} - The chosen alternative index
*/
return function () {
var nextToken = this.LA(1);
return choiceToAlt_1[nextToken.tokenTypeIdx];
};
}
else {
// optimized lookahead without needing to check the predicates at all.
// this causes code duplication which is intentional to improve performance.
/**
* @returns {number} - The chosen alternative index
*/
return function () {
for (var t = 0; t < numOfAlts; t++) {
var currAlt = alts[t];
var currNumOfPaths = currAlt.length;
nextPath: for (var j = 0; j < currNumOfPaths; j++) {
var currPath = currAlt[j];
var currPathLength = currPath.length;
for (var i = 0; i < currPathLength; i++) {
var nextToken = this.LA(i + 1);
if (tokenMatcher(nextToken, currPath[i]) === false) {
// mismatch in current path
// try the next pth
continue nextPath;
}
}
// found a full path that matches.
// this will also work for an empty ALT as the loop will be skipped
return t;
}
// none of the paths for the current alternative matched
// try the next alternative
}
// none of the alternatives could be matched
return undefined;
};
}
}
exports.buildAlternativesLookAheadFunc = buildAlternativesLookAheadFunc;
function buildSingleAlternativeLookaheadFunction(alt, tokenMatcher, dynamicTokensEnabled) {
var areAllOneTokenLookahead = utils_1.every(alt, function (currPath) {
return currPath.length === 1;
});
var numOfPaths = alt.length;
// optimized (common) case of all the lookaheads paths requiring only
// a single token lookahead.
if (areAllOneTokenLookahead && !dynamicTokensEnabled) {
var singleTokensTypes = utils_1.flatten(alt);
if (singleTokensTypes.length === 1 &&
utils_1.isEmpty(singleTokensTypes[0].categoryMatches)) {
var expectedTokenType = singleTokensTypes[0];
var expectedTokenUniqueKey_1 = expectedTokenType.tokenTypeIdx;
return function () {
return this.LA(1).tokenTypeIdx === expectedTokenUniqueKey_1;
};
}
else {
var choiceToAlt_2 = utils_1.reduce(singleTokensTypes, function (result, currTokType, idx) {
result[currTokType.tokenTypeIdx] = true;
utils_1.forEach(currTokType.categoryMatches, function (currExtendingType) {
result[currExtendingType] = true;
});
return result;
}, []);
return function () {
var nextToken = this.LA(1);
return choiceToAlt_2[nextToken.tokenTypeIdx] === true;
};
}
}
else {
return function () {
nextPath: for (var j = 0; j < numOfPaths; j++) {
var currPath = alt[j];
var currPathLength = currPath.length;
for (var i = 0; i < currPathLength; i++) {
var nextToken = this.LA(i + 1);
if (tokenMatcher(nextToken, currPath[i]) === false) {
// mismatch in current path
// try the next pth
continue nextPath;
}
}
// found a full path that matches.
return true;
}
// none of the paths matched
return false;
};
}
}
exports.buildSingleAlternativeLookaheadFunction = buildSingleAlternativeLookaheadFunction;
var RestDefinitionFinderWalker = /** @class */ (function (_super) {
__extends(RestDefinitionFinderWalker, _super);
function RestDefinitionFinderWalker(topProd, targetOccurrence, targetProdType) {
var _this = _super.call(this) || this;
_this.topProd = topProd;
_this.targetOccurrence = targetOccurrence;
_this.targetProdType = targetProdType;
return _this;
}
RestDefinitionFinderWalker.prototype.startWalking = function () {
this.walk(this.topProd);
return this.restDef;
};
RestDefinitionFinderWalker.prototype.checkIsTarget = function (node, expectedProdType, currRest, prevRest) {
if (node.idx === this.targetOccurrence &&
this.targetProdType === expectedProdType) {
this.restDef = currRest.concat(prevRest);
return true;
}
// performance optimization, do not iterate over the entire Grammar ast after we have found the target
return false;
};
RestDefinitionFinderWalker.prototype.walkOption = function (optionProd, currRest, prevRest) {
if (!this.checkIsTarget(optionProd, PROD_TYPE.OPTION, currRest, prevRest)) {
_super.prototype.walkOption.call(this, optionProd, currRest, prevRest);
}
};
RestDefinitionFinderWalker.prototype.walkAtLeastOne = function (atLeastOneProd, currRest, prevRest) {
if (!this.checkIsTarget(atLeastOneProd, PROD_TYPE.REPETITION_MANDATORY, currRest, prevRest)) {
_super.prototype.walkOption.call(this, atLeastOneProd, currRest, prevRest);
}
};
RestDefinitionFinderWalker.prototype.walkAtLeastOneSep = function (atLeastOneSepProd, currRest, prevRest) {
if (!this.checkIsTarget(atLeastOneSepProd, PROD_TYPE.REPETITION_MANDATORY_WITH_SEPARATOR, currRest, prevRest)) {
_super.prototype.walkOption.call(this, atLeastOneSepProd, currRest, prevRest);
}
};
RestDefinitionFinderWalker.prototype.walkMany = function (manyProd, currRest, prevRest) {
if (!this.checkIsTarget(manyProd, PROD_TYPE.REPETITION, currRest, prevRest)) {
_super.prototype.walkOption.call(this, manyProd, currRest, prevRest);
}
};
RestDefinitionFinderWalker.prototype.walkManySep = function (manySepProd, currRest, prevRest) {
if (!this.checkIsTarget(manySepProd, PROD_TYPE.REPETITION_WITH_SEPARATOR, currRest, prevRest)) {
_super.prototype.walkOption.call(this, manySepProd, currRest, prevRest);
}
};
return RestDefinitionFinderWalker;
}(rest_1.RestWalker));
/**
* Returns the definition of a target production in a top level level rule.
*/
var InsideDefinitionFinderVisitor = /** @class */ (function (_super) {
__extends(InsideDefinitionFinderVisitor, _super);
function InsideDefinitionFinderVisitor(targetOccurrence, targetProdType, targetRef) {
var _this = _super.call(this) || this;
_this.targetOccurrence = targetOccurrence;
_this.targetProdType = targetProdType;
_this.targetRef = targetRef;
_this.result = [];
return _this;
}
InsideDefinitionFinderVisitor.prototype.checkIsTarget = function (node, expectedProdName) {
if (node.idx === this.targetOccurrence &&
this.targetProdType === expectedProdName &&
(this.targetRef === undefined || node === this.targetRef)) {
this.result = node.definition;
}
};
InsideDefinitionFinderVisitor.prototype.visitOption = function (node) {
this.checkIsTarget(node, PROD_TYPE.OPTION);
};
InsideDefinitionFinderVisitor.prototype.visitRepetition = function (node) {
this.checkIsTarget(node, PROD_TYPE.REPETITION);
};
InsideDefinitionFinderVisitor.prototype.visitRepetitionMandatory = function (node) {
this.checkIsTarget(node, PROD_TYPE.REPETITION_MANDATORY);
};
InsideDefinitionFinderVisitor.prototype.visitRepetitionMandatoryWithSeparator = function (node) {
this.checkIsTarget(node, PROD_TYPE.REPETITION_MANDATORY_WITH_SEPARATOR);
};
InsideDefinitionFinderVisitor.prototype.visitRepetitionWithSeparator = function (node) {
this.checkIsTarget(node, PROD_TYPE.REPETITION_WITH_SEPARATOR);
};
InsideDefinitionFinderVisitor.prototype.visitAlternation = function (node) {
this.checkIsTarget(node, PROD_TYPE.ALTERNATION);
};
return InsideDefinitionFinderVisitor;
}(gast_visitor_public_1.GAstVisitor));
function initializeArrayOfArrays(size) {
var result = new Array(size);
for (var i = 0; i < size; i++) {
result[i] = [];
}
return result;
}
/**
* A sort of hash function between a Path in the grammar and a string.
* Note that this returns multiple "hashes" to support the scenario of token categories.
* - A single path with categories may match multiple **actual** paths.
*/
function pathToHashKeys(path) {
var keys = [""];
for (var i = 0; i < path.length; i++) {
var tokType = path[i];
var longerKeys = [];
for (var j = 0; j < keys.length; j++) {
var currShorterKey = keys[j];
longerKeys.push(currShorterKey + "_" + tokType.tokenTypeIdx);
for (var t = 0; t < tokType.categoryMatches.length; t++) {
var categoriesKeySuffix = "_" + tokType.categoryMatches[t];
longerKeys.push(currShorterKey + categoriesKeySuffix);
}
}
keys = longerKeys;
}
return keys;
}
/**
* Imperative style due to being called from a hot spot
*/
function isUniquePrefixHash(altKnownPathsKeys, searchPathKeys, idx) {
for (var currAltIdx = 0; currAltIdx < altKnownPathsKeys.length; currAltIdx++) {
// We only want to test vs the other alternatives
if (currAltIdx === idx) {
continue;
}
var otherAltKnownPathsKeys = altKnownPathsKeys[currAltIdx];
for (var searchIdx = 0; searchIdx < searchPathKeys.length; searchIdx++) {
var searchKey = searchPathKeys[searchIdx];
if (otherAltKnownPathsKeys[searchKey] === true) {
return false;
}
}
}
// None of the SearchPathKeys were found in any of the other alternatives
return true;
}
function lookAheadSequenceFromAlternatives(altsDefs, k) {
var partialAlts = utils_1.map(altsDefs, function (currAlt) { return interpreter_1.possiblePathsFrom([currAlt], 1); });
var finalResult = initializeArrayOfArrays(partialAlts.length);
var altsHashes = utils_1.map(partialAlts, function (currAltPaths) {
var dict = {};
utils_1.forEach(currAltPaths, function (item) {
var keys = pathToHashKeys(item.partialPath);
utils_1.forEach(keys, function (currKey) {
dict[currKey] = true;
});
});
return dict;
});
var newData = partialAlts;
// maxLookahead loop
for (var pathLength = 1; pathLength <= k; pathLength++) {
var currDataset = newData;
newData = initializeArrayOfArrays(currDataset.length);
var _loop_1 = function (altIdx) {
var currAltPathsAndSuffixes = currDataset[altIdx];
// paths in current alternative loop
for (var currPathIdx = 0; currPathIdx < currAltPathsAndSuffixes.length; currPathIdx++) {
var currPathPrefix = currAltPathsAndSuffixes[currPathIdx].partialPath;
var suffixDef = currAltPathsAndSuffixes[currPathIdx].suffixDef;
var prefixKeys = pathToHashKeys(currPathPrefix);
var isUnique = isUniquePrefixHash(altsHashes, prefixKeys, altIdx);
// End of the line for this path.
if (isUnique || utils_1.isEmpty(suffixDef) || currPathPrefix.length === k) {
var currAltResult = finalResult[altIdx];
// TODO: Can we implement a containsPath using Maps/Dictionaries?
if (containsPath(currAltResult, currPathPrefix) === false) {
currAltResult.push(currPathPrefix);
// Update all new keys for the current path.
for (var j = 0; j < prefixKeys.length; j++) {
var currKey = prefixKeys[j];
altsHashes[altIdx][currKey] = true;
}
}
}
// Expand longer paths
else {
var newPartialPathsAndSuffixes = interpreter_1.possiblePathsFrom(suffixDef, pathLength + 1, currPathPrefix);
newData[altIdx] = newData[altIdx].concat(newPartialPathsAndSuffixes);
// Update keys for new known paths
utils_1.forEach(newPartialPathsAndSuffixes, function (item) {
var prefixKeys = pathToHashKeys(item.partialPath);
utils_1.forEach(prefixKeys, function (key) {
altsHashes[altIdx][key] = true;
});
});
}
}
};
// alternatives loop
for (var altIdx = 0; altIdx < currDataset.length; altIdx++) {
_loop_1(altIdx);
}
}
return finalResult;
}
exports.lookAheadSequenceFromAlternatives = lookAheadSequenceFromAlternatives;
function getLookaheadPathsForOr(occurrence, ruleGrammar, k, orProd) {
var visitor = new InsideDefinitionFinderVisitor(occurrence, PROD_TYPE.ALTERNATION, orProd);
ruleGrammar.accept(visitor);
return lookAheadSequenceFromAlternatives(visitor.result, k);
}
exports.getLookaheadPathsForOr = getLookaheadPathsForOr;
function getLookaheadPathsForOptionalProd(occurrence, ruleGrammar, prodType, k) {
var insideDefVisitor = new InsideDefinitionFinderVisitor(occurrence, prodType);
ruleGrammar.accept(insideDefVisitor);
var insideDef = insideDefVisitor.result;
var afterDefWalker = new RestDefinitionFinderWalker(ruleGrammar, occurrence, prodType);
var afterDef = afterDefWalker.startWalking();
var insideFlat = new gast_public_1.Alternative({ definition: insideDef });
var afterFlat = new gast_public_1.Alternative({ definition: afterDef });
return lookAheadSequenceFromAlternatives([insideFlat, afterFlat], k);
}
exports.getLookaheadPathsForOptionalProd = getLookaheadPathsForOptionalProd;
function containsPath(alternative, searchPath) {
compareOtherPath: for (var i = 0; i < alternative.length; i++) {
var otherPath = alternative[i];
if (otherPath.length !== searchPath.length) {
continue;
}
for (var j = 0; j < otherPath.length; j++) {
var searchTok = searchPath[j];
var otherTok = otherPath[j];
var matchingTokens = searchTok === otherTok ||
otherTok.categoryMatchesMap[searchTok.tokenTypeIdx] !== undefined;
if (matchingTokens === false) {
continue compareOtherPath;
}
}
return true;
}
return false;
}
exports.containsPath = containsPath;
function isStrictPrefixOfPath(prefix, other) {
return (prefix.length < other.length &&
utils_1.every(prefix, function (tokType, idx) {
var otherTokType = other[idx];
return (tokType === otherTokType ||
otherTokType.categoryMatchesMap[tokType.tokenTypeIdx]);
}));
}
exports.isStrictPrefixOfPath = isStrictPrefixOfPath;
function areTokenCategoriesNotUsed(lookAheadPaths) {
return utils_1.every(lookAheadPaths, function (singleAltPaths) {
return utils_1.every(singleAltPaths, function (singlePath) {
return utils_1.every(singlePath, function (token) { return utils_1.isEmpty(token.categoryMatches); });
});
});
}
exports.areTokenCategoriesNotUsed = areTokenCategoriesNotUsed;
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