mirror of
https://github.com/Jermolene/TiddlyWiki5
synced 2024-12-12 11:10:27 +00:00
138 lines
4.4 KiB
JavaScript
138 lines
4.4 KiB
JavaScript
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"use strict";
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/**
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* Plugin for Remarkable Markdown processor which transforms $..$ and $$..$$ sequences into math HTML using the
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* Katex package.
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*/
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const rkatex = (md, options) => {
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const backslash = '\\';
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const dollar = '$';
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const opts = options || {};
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const delimiter = opts.delimiter || dollar;
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if (delimiter.length !== 1) { throw new Error('invalid delimiter'); }
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const katex = require("katex");
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/**
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* Render the contents as KaTeX
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*/
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const renderKatex = (source, displayMode) => katex.renderToString(source,
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{displayMode: displayMode,
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throwOnError: false});
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/**
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* Parse '$$' as a block. Based off of similar method in remarkable.
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*/
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const parseBlockKatex = (state, startLine, endLine) => {
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let haveEndMarker = false;
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let pos = state.bMarks[startLine] + state.tShift[startLine];
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let max = state.eMarks[startLine];
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if (pos + 1 > max) { return false; }
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const marker = state.src.charAt(pos);
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if (marker !== delimiter) { return false; }
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// scan marker length
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let mem = pos;
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pos = state.skipChars(pos, marker);
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let len = pos - mem;
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if (len !== 2) { return false; }
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// search end of block
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let nextLine = startLine;
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for (;;) {
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++nextLine;
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if (nextLine >= endLine) { break; }
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pos = mem = state.bMarks[nextLine] + state.tShift[nextLine];
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max = state.eMarks[nextLine];
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if (pos < max && state.tShift[nextLine] < state.blkIndent) { break; }
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if (state.src.charAt(pos) !== delimiter) { continue; }
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if (state.tShift[nextLine] - state.blkIndent >= 4) { continue; }
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pos = state.skipChars(pos, marker);
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if (pos - mem < len) { continue; }
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pos = state.skipSpaces(pos);
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if (pos < max) { continue; }
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haveEndMarker = true;
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break;
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}
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// If a fence has heading spaces, they should be removed from its inner block
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len = state.tShift[startLine];
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state.line = nextLine + (haveEndMarker ? 1 : 0);
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const content = state.getLines(startLine + 1, nextLine, len, true)
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.replace(/[ \n]+/g, ' ')
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.trim();
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state.tokens.push({type: 'katex', params: null, content: content, lines: [startLine, state.line],
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level: state.level, block: true});
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return true;
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};
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/**
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* Look for '$' or '$$' spans in Markdown text. Based off of the 'fenced' parser in remarkable.
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*/
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const parseInlineKatex = (state, silent) => {
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const start = state.pos;
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const max = state.posMax;
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let pos = start;
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// Unexpected starting character
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if (state.src.charAt(pos) !== delimiter) { return false; }
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++pos;
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while (pos < max && state.src.charAt(pos) === delimiter) { ++pos; }
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// Capture the length of the starting delimiter -- closing one must match in size
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const marker = state.src.slice(start, pos);
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if (marker.length > 2) { return false; }
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const spanStart = pos;
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let escapedDepth = 0;
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while (pos < max) {
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const char = state.src.charAt(pos);
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if (char === '{' && (pos == 0 || state.src.charAt(pos - 1) != backslash)) {
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escapedDepth += 1;
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} else if (char === '}' && (pos == 0 || state.src.charAt(pos - 1) != backslash)) {
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escapedDepth -= 1;
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if (escapedDepth < 0) { return false; }
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} else if (char === delimiter && escapedDepth === 0) {
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const matchStart = pos;
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let matchEnd = pos + 1;
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while (matchEnd < max && state.src.charAt(matchEnd) === delimiter) { ++matchEnd; }
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if (matchEnd - matchStart === marker.length) {
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if (!silent) {
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const content = state.src.slice(spanStart, matchStart)
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.replace(/[ \n]+/g, ' ')
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.trim();
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state.push({type: 'katex', content: content, block: marker.length > 1, level: state.level});
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}
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state.pos = matchEnd;
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return true;
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}
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}
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pos += 1;
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}
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if (!silent) { state.pending += marker; }
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state.pos += marker.length;
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return true;
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};
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md.inline.ruler.push('katex', parseInlineKatex, options);
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md.block.ruler.push('katex', parseBlockKatex, options);
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md.renderer.rules.katex = (tokens, idx) => renderKatex(tokens[idx].content, tokens[idx].block);
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md.renderer.rules.katex.delimiter = delimiter;
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};
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module.exports = rkatex;
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