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Contents
/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
/**
* Flattens a nested disjunction node to a list.
*
* /a|b|c|d/
*
* {{{a, b}, c}, d} -> [a, b, c, d]
*/
function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }
function disjunctionToList(node) {
if (node.type !== 'Disjunction') {
throw new TypeError('Expected "Disjunction" node, got "' + node.type + '"');
}
var list = [];
if (node.left && node.left.type === 'Disjunction') {
list.push.apply(list, _toConsumableArray(disjunctionToList(node.left)).concat([node.right]));
} else {
list.push(node.left, node.right);
}
return list;
}
/**
* Builds a nested disjunction node from a list.
*
* /a|b|c|d/
*
* [a, b, c, d] -> {{{a, b}, c}, d}
*/
function listToDisjunction(list) {
return list.reduce(function (left, right) {
return {
type: 'Disjunction',
left: left,
right: right
};
});
}
/**
* Increases a quantifier by one.
* Does not change greediness.
* * -> +
* + -> {2,}
* ? -> {1,2}
* {2} -> {3}
* {2,} -> {3,}
* {2,3} -> {3,4}
*/
function increaseQuantifierByOne(quantifier) {
if (quantifier.kind === '*') {
quantifier.kind = '+';
} else if (quantifier.kind === '+') {
quantifier.kind = 'Range';
quantifier.from = 2;
delete quantifier.to;
} else if (quantifier.kind === '?') {
quantifier.kind = 'Range';
quantifier.from = 1;
quantifier.to = 2;
} else if (quantifier.kind === 'Range') {
quantifier.from += 1;
if (quantifier.to) {
quantifier.to += 1;
}
}
}
module.exports = {
disjunctionToList: disjunctionToList,
listToDisjunction: listToDisjunction,
increaseQuantifierByOne: increaseQuantifierByOne
};
Version data entries
10 entries across 10 versions & 3 rubygems