jscc-parser
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A LALR(1) Parser Generator for JavaScript written in JavaScript.
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<h1 class="page-title">Source: first.js</h1>
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<pre class="prettyprint source linenums"><code>/*
* Universal module definition for first.
*/
(function(root, factory) {
/* istanbul ignore next */
if (typeof define === 'function' && define.amd) {
define(['require', './global', './util', './enums/SYM'], factory);
} else if (typeof module === 'object' && module.exports) {
module.exports = factory(require);
} else {
root.jsccfirst = factory(function(mod) {
return root["jscc" + mod.split("/").pop()];
});
}
}(this,
/**
* @param {reqParameter} require
* @param {...*} others
* @returns {jscc.first}
*/
function(require, others) {
//>>excludeStart("closure", pragmas.closure);
var jscc = {};
//>>excludeEnd("closure");
var global = /** @type {jscc.global} */ (require("./global")),
util = /** @type {jscc.util} */ (require("./util")),
SYM = require("./enums/SYM");
/**
* Creates an instance of jscc.first.
* @classdesc Functions relating to FIRST-sets.
* @constructor
*/
jscc.first = function() {
};
/**
* Computes the FIRST-sets for all non-terminals of the grammar.
* Must be called right after the parse and before the table
* generation methods are performed.
* @author Jan Max Meyer
*/
jscc.first.prototype.first = function() {
var cnt = 0,
old_cnt = 0;
var nullable;
do {
old_cnt = cnt;
cnt = 0;
for (var i = 0; i < global.symbols.length; i++) {
if (global.symbols[i].kind == SYM.NONTERM) {
for (var j = 0; j < global.symbols[i].prods.length; j++) {
nullable = false;
for (var k = 0; k < global.productions[global.symbols[i].prods[j]].rhs.length; k++) {
global.symbols[i].first = util.union(global.symbols[i].first,
global.symbols[global.productions[global.symbols[i].prods[j]].rhs[k]].first);
nullable =
global.symbols[global.productions[global.symbols[i].prods[j]].rhs[k]].nullable;
if (!nullable) {
break;
}
}
cnt += global.symbols[i].first.length;
if (k == global.productions[global.symbols[i].prods[j]].rhs.length) {
nullable = true;
}
if (nullable) {
global.symbols[i].nullable = true;
}
}
}
}
} while (cnt != old_cnt);
};
/**
* Returns all terminals that are possible from a given position
* of a production's right-hand side.
* @param {jscc.classes.Item} item - Item to which the lookaheads are added.
* @param {jscc.classes.Production} p - The production where the computation
* should be done.
* @param {number} begin - The offset of the symbol where the
* rhs_first() begins its calculations.
* @returns {boolean} True if the whole rest of the right-hand side
* can be null (epsilon), else false.
* @author Jan Max Meyer
*/
jscc.first.prototype.rhs_first = function(item, p, begin) {
var i;
for (i = begin; i < p.rhs.length; i++) {
item.lookahead = util.union(item.lookahead, global.symbols[p.rhs[i]].first);
if (!global.symbols[p.rhs[i]].nullable) {
return false;
}
}
return true;
};
/**
* Functions relating to FIRST-sets.
* @module {jscc.first} jscc/first
* @requires module:jscc/global
* @requires module:jscc/util
*/
return new jscc.first();
}));
</code></pre>
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<h2><a href="index.html">Home</a></h2><h3>Modules</h3><ul><li><a href="module-jscc.html">jscc</a></li><li><a href="module-jscc_bitset_BitSet32.html">jscc/bitset/BitSet32</a></li><li><a href="module-jscc_bitset_BitSetBool.html">jscc/bitset/BitSetBool</a></li><li><a href="module-jscc_bitset_BitSetJava.html">jscc/bitset/BitSetJava</a></li><li><a href="module-jscc_classes_Dfa.html">jscc/classes/Dfa</a></li><li><a href="module-jscc_classes_Item.html">jscc/classes/Item</a></li><li><a href="module-jscc_classes_Nfa.html">jscc/classes/Nfa</a></li><li><a href="module-jscc_classes_Param.html">jscc/classes/Param</a></li><li><a href="module-jscc_classes_Production.html">jscc/classes/Production</a></li><li><a href="module-jscc_classes_State.html">jscc/classes/State</a></li><li><a href="module-jscc_classes_Symbol.html">jscc/classes/Symbol</a></li><li><a href="module-jscc_classes_TableEntry.html">jscc/classes/TableEntry</a></li><li><a href="module-jscc_enums_ASSOC.html">jscc/enums/ASSOC</a></li><li><a href="module-jscc_enums_EDGE.html">jscc/enums/EDGE</a></li><li><a href="module-jscc_enums_EXEC.html">jscc/enums/EXEC</a></li><li><a href="module-jscc_enums_LOG_LEVEL.html">jscc/enums/LOG_LEVEL</a></li><li><a href="module-jscc_enums_MODE_GEN.html">jscc/enums/MODE_GEN</a></li><li><a href="module-jscc_enums_SPECIAL.html">jscc/enums/SPECIAL</a></li><li><a href="module-jscc_enums_SYM.html">jscc/enums/SYM</a></li><li><a href="module-jscc_first.html">jscc/first</a></li><li><a href="module-jscc_global.html">jscc/global</a></li><li><a href="module-jscc_integrity.html">jscc/integrity</a></li><li><a href="module-jscc_io_io.html">jscc/io/io</a></li><li><a href="module-jscc_lexdbg.html">jscc/lexdbg</a></li><li><a href="module-jscc_lexdfa.html">jscc/lexdfa</a></li><li><a href="module-jscc_log_log.html">jscc/log/log</a></li><li><a href="module-jscc_parse.html">jscc/parse</a></li><li><a href="module-jscc_printtab.html">jscc/printtab</a></li><li><a href="module-jscc_regex.html">jscc/regex</a></li><li><a href="module-jscc_util.html">jscc/util</a></li></ul><h3>Classes</h3><ul><li><a href="-_anonymous_-jscc.BitSet32.html">BitSet32</a></li><li><a href="-_anonymous_-jscc.BitSetBool.html">BitSetBool</a></li><li><a href="-_anonymous_-jscc.BitSetJava.html">BitSetJava</a></li><li><a href="-_anonymous_-jscc.classes.Dfa.html">classes.Dfa</a></li><li><a href="-_anonymous_-jscc.first.html">first</a></li><li><a href="-_anonymous_-jscc.global.html">global</a></li><li><a href="-_anonymous_-jscc.integrity.html">integrity</a></li><li><a href="-_anonymous_-jscc.ioBrowser.html">ioBrowser</a></li><li><a href="-_anonymous_-jscc.ioNashorn.html">ioNashorn</a></li><li><a href="-_anonymous_-jscc.ioNode.html">ioNode</a></li><li><a href="-_anonymous_-jscc.ioRhino.html">ioRhino</a></li><li><a href="-_anonymous_-jscc.lexdbg.html">lexdbg</a></li><li><a href="-_anonymous_-jscc.lexdfa.html">lexdfa</a></li><li><a href="-_anonymous_-jscc.logBrowser.html">logBrowser</a></li><li><a href="-_anonymous_-jscc.logJava.html">logJava</a></li><li><a href="-_anonymous_-jscc.logNode.html">logNode</a></li><li><a href="-_anonymous_-jscc.printtab.html">printtab</a></li><li><a href="-_anonymous_-jscc.util.html">util</a></li><li><a href="jscc_debug.html">jscc/debug</a></li><li><a href="jscc_nfaStates.html">jscc/nfaStates</a></li><li><a href="jscc_tabgen.html">jscc/tabgen</a></li><li><a href="%257Bjscc.classes%257D.jscc.classes.State.html">jscc.classes.State</a></li></ul><h3>Namespaces</h3><ul><li><a href="jscc.debug.html">debug</a></li></ul><h3>Interfaces</h3><ul><li><a href="jscc.bitset.html">bitset</a></li><li><a href="jscc.io.html">io</a></li><li><a href="jscc.log.html">log</a></li></ul><h3><a href="global.html">Global</a></h3>
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Documentation generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 3.4.0</a> on Mon Aug 01 2016 11:09:19 GMT-0500 (Central Daylight Time)
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