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141 lines
3.7 KiB
141 lines
3.7 KiB
// Process *this* and _that_
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'use strict';
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function isAlphaNum(code) {
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return (code >= 0x30 /* 0 */ && code <= 0x39 /* 9 */) ||
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(code >= 0x41 /* A */ && code <= 0x5A /* Z */) ||
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(code >= 0x61 /* a */ && code <= 0x7A /* z */);
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}
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// parse sequence of emphasis markers,
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// "start" should point at a valid marker
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function scanDelims(state, start) {
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var pos = start, lastChar, nextChar, count,
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can_open = true,
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can_close = true,
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max = state.posMax,
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marker = state.src.charCodeAt(start);
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lastChar = start > 0 ? state.src.charCodeAt(start - 1) : -1;
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while (pos < max && state.src.charCodeAt(pos) === marker) { pos++; }
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if (pos >= max) { can_open = false; }
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count = pos - start;
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nextChar = pos < max ? state.src.charCodeAt(pos) : -1;
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// check whitespace conditions
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if (nextChar === 0x20 || nextChar === 0x0A) { can_open = false; }
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if (lastChar === 0x20 || lastChar === 0x0A) { can_close = false; }
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if (marker === 0x5F /* _ */) {
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// check if we aren't inside the word
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if (isAlphaNum(lastChar)) { can_open = false; }
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if (isAlphaNum(nextChar)) { can_close = false; }
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}
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return {
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can_open: can_open,
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can_close: can_close,
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delims: count
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};
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}
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module.exports = function emphasis(state, silent) {
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var startCount,
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count,
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found,
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oldCount,
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newCount,
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stack,
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res,
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max = state.posMax,
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start = state.pos,
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marker = state.src.charCodeAt(start);
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if (marker !== 0x5F/* _ */ && marker !== 0x2A /* * */) { return false; }
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if (silent) { return false; } // don't run any pairs in validation mode
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res = scanDelims(state, start);
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startCount = res.delims;
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if (!res.can_open) {
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state.pos += startCount;
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// Earlier we checked !silent, but this implementation does not need it
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state.pending += state.src.slice(start, state.pos);
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return true;
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}
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state.pos = start + startCount;
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stack = [ startCount ];
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while (state.pos < max) {
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if (state.src.charCodeAt(state.pos) === marker) {
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res = scanDelims(state, state.pos);
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count = res.delims;
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if (res.can_close) {
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oldCount = stack.pop();
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newCount = count;
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while (oldCount !== newCount) {
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if (newCount < oldCount) {
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stack.push(oldCount - newCount);
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break;
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}
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// assert(newCount > oldCount)
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newCount -= oldCount;
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if (stack.length === 0) { break; }
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state.pos += oldCount;
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oldCount = stack.pop();
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}
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if (stack.length === 0) {
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startCount = oldCount;
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found = true;
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break;
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}
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state.pos += count;
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continue;
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}
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if (res.can_open) { stack.push(count); }
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state.pos += count;
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continue;
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}
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state.md.inline.skipToken(state);
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}
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if (!found) {
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// parser failed to find ending tag, so it's not valid emphasis
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state.pos = start;
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return false;
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}
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// found!
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state.posMax = state.pos;
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state.pos = start + startCount;
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// Earlier we checked !silent, but this implementation does not need it
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// we have `startCount` starting and ending markers,
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// now trying to serialize them into tokens
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for (count = startCount; count > 1; count -= 2) {
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state.push({ type: 'strong_open', level: state.level++ });
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}
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if (count % 2) { state.push({ type: 'em_open', level: state.level++ }); }
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state.md.inline.tokenize(state);
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if (count % 2) { state.push({ type: 'em_close', level: --state.level }); }
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for (count = startCount; count > 1; count -= 2) {
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state.push({ type: 'strong_close', level: --state.level });
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}
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state.pos = state.posMax + startCount;
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state.posMax = max;
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return true;
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};
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