242 lines
8.2 KiB
TypeScript
242 lines
8.2 KiB
TypeScript
/*************************************************************
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*
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* Copyright (c) 2017-2022 The MathJax Consortium
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @fileoverview Implements the TeX version of the FindMath object
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*
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* @author dpvc@mathjax.org (Davide Cervone)
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*/
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import {AbstractFindMath} from '../../core/FindMath.js';
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import {OptionList} from '../../util/Options.js';
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import {sortLength, quotePattern} from '../../util/string.js';
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import {ProtoItem, protoItem} from '../../core/MathItem.js';
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/**
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* Shorthand types for data about end delimiters and delimiter pairs
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*/
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export type EndItem = [string, boolean, RegExp];
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export type Delims = [string, string];
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/*****************************************************************/
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/*
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* Implements the FindTeX class (extends AbstractFindMath)
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*
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* Locates TeX expressions within strings
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*/
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/*
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* @template N The HTMLElement node class
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* @template T The Text node class
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* @template D The Document class
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*/
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export class FindTeX<N, T, D> extends AbstractFindMath<N, T, D> {
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/**
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* @type {OptionList}
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*/
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public static OPTIONS: OptionList = {
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inlineMath: [ // The start/end delimiter pairs for in-line math
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// ['$', '$'], // (comment out any you don't want, or add your own, but
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['\\(', '\\)'] // be sure that you don't have an extra comma at the end)
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],
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displayMath: [ // The start/end delimiter pairs for display math
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['$$', '$$'], // (comment out any you don't want, or add your own, but
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['\\[', '\\]'] // be sure that you don't have an extra comma at the end)
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],
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processEscapes: true, // set to true to allow \$ to produce a dollar without
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// starting in-line math mode
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processEnvironments: true, // set to true to process \begin{xxx}...\end{xxx} outside
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// of math mode, false to prevent that
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processRefs: true, // set to true to process \ref{...} outside of math mode
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};
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/**
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* The regular expression for any starting delimiter
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*/
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protected start: RegExp;
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/**
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* The end-delimiter data keyed to the opening delimiter string
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*/
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protected end: {[name: string]: EndItem};
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/**
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* False if the configuration has no delimiters (so search can be skipped), true otherwise
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*/
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protected hasPatterns: boolean;
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/**
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* The index of the \begin...\end pattern in the regex match array
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*/
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protected env: number;
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/**
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* The index of the \ref and escaped character patters in the regex match array
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*/
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protected sub: number;
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/**
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* @override
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*/
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constructor(options: OptionList) {
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super(options);
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this.getPatterns();
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}
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/**
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* Create the patterns needed for searching the strings for TeX
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* based on the configuration options
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*/
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protected getPatterns() {
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let options = this.options;
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let starts: string[] = [], parts: string[] = [], subparts: string[] = [];
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this.end = {};
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this.env = this.sub = 0;
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let i = 1;
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options['inlineMath'].forEach((delims: Delims) => this.addPattern(starts, delims, false));
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options['displayMath'].forEach((delims: Delims) => this.addPattern(starts, delims, true));
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if (starts.length) {
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parts.push(starts.sort(sortLength).join('|'));
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}
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if (options['processEnvironments']) {
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parts.push('\\\\begin\\s*\\{([^}]*)\\}');
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this.env = i;
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i++;
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}
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if (options['processEscapes']) {
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subparts.push('\\\\([\\\\$])');
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}
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if (options['processRefs']) {
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subparts.push('(\\\\(?:eq)?ref\\s*\\{[^}]*\\})');
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}
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if (subparts.length) {
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parts.push('(' + subparts.join('|') + ')');
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this.sub = i;
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}
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this.start = new RegExp(parts.join('|'), 'g');
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this.hasPatterns = (parts.length > 0);
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}
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/**
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* Add the needed patterns for a pair of delimiters
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*
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* @param {string[]} starts Array of starting delimiter strings
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* @param {Delims} delims Array of delimiter strings, as [start, end]
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* @param {boolean} display True if the delimiters are for display mode
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*/
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protected addPattern(starts: string[], delims: Delims, display: boolean) {
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let [open, close] = delims;
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starts.push(quotePattern(open));
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this.end[open] = [close, display, this.endPattern(close)];
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}
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/**
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* Create the pattern for a close delimiter
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*
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* @param {string} end The end delimiter text
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* @param {string} endp The end delimiter pattern (overrides the literal end pattern)
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* @return {RegExp} The regular expression for the end delimiter
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*/
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protected endPattern(end: string, endp?: string): RegExp {
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return new RegExp((endp || quotePattern(end)) + '|\\\\(?:[a-zA-Z]|.)|[{}]', 'g');
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}
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/**
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* Search for the end delimiter given the start delimiter,
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* skipping braced groups, and control sequences that aren't
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* the close delimiter.
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*
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* @param {string} text The string being searched for the end delimiter
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* @param {number} n The index of the string being searched
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* @param {RegExpExecArray} start The result array from the start-delimiter search
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* @param {EndItem} end The end-delimiter data corresponding to the start delimiter
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* @return {ProtoItem<N,T>} The proto math item for the math, if found
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*/
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protected findEnd(text: string, n: number, start: RegExpExecArray, end: EndItem): ProtoItem<N, T> {
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let [close, display, pattern] = end;
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let i = pattern.lastIndex = start.index + start[0].length;
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let match: RegExpExecArray, braces: number = 0;
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while ((match = pattern.exec(text))) {
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if ((match[1] || match[0]) === close && braces === 0) {
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return protoItem<N, T>(start[0], text.substr(i, match.index - i), match[0],
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n, start.index, match.index + match[0].length, display);
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} else if (match[0] === '{') {
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braces++;
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} else if (match[0] === '}' && braces) {
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braces--;
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}
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}
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return null;
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}
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/**
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* Search a string for math delimited by one of the delimiter pairs,
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* or by \begin{env}...\end{env}, or \eqref{...}, \ref{...}, \\, or \$.
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*
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* @param {ProtoItem[]} math The array of proto math items located so far
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* @param {number} n The index of the string being searched
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* @param {string} text The string being searched
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*/
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protected findMathInString(math: ProtoItem<N, T>[], n: number, text: string) {
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let start, match;
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this.start.lastIndex = 0;
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while ((start = this.start.exec(text))) {
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if (start[this.env] !== undefined && this.env) {
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let end = '\\\\end\\s*(\\{' + quotePattern(start[this.env]) + '\\})';
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match = this.findEnd(text, n, start, ['{' + start[this.env] + '}', true, this.endPattern(null, end)]);
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if (match) {
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match.math = match.open + match.math + match.close;
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match.open = match.close = '';
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}
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} else if (start[this.sub] !== undefined && this.sub) {
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let math = start[this.sub];
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let end = start.index + start[this.sub].length;
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if (math.length === 2) {
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match = protoItem<N, T>('', math.substr(1), '', n, start.index, end);
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} else {
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match = protoItem<N, T>('', math, '', n, start.index, end, false);
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}
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} else {
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match = this.findEnd(text, n, start, this.end[start[0]]);
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}
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if (match) {
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math.push(match);
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this.start.lastIndex = match.end.n;
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}
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}
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}
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/**
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* Search for math in an array of strings and return an array of matches.
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*
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* @override
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*/
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public findMath(strings: string[]) {
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let math: ProtoItem<N, T>[] = [];
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if (this.hasPatterns) {
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for (let i = 0, m = strings.length; i < m; i++) {
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this.findMathInString(math, i, strings[i]);
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}
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}
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return math;
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}
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}
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