295 lines
8.3 KiB
JavaScript
295 lines
8.3 KiB
JavaScript
/**
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* @typedef {import('micromark-util-types').Code} Code
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* @typedef {import('micromark-util-types').Construct} Construct
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* @typedef {import('micromark-util-types').Event} Event
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* @typedef {import('micromark-util-types').Point} Point
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* @typedef {import('micromark-util-types').Resolver} Resolver
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* @typedef {import('micromark-util-types').State} State
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* @typedef {import('micromark-util-types').Token} Token
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* @typedef {import('micromark-util-types').TokenizeContext} TokenizeContext
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* @typedef {import('micromark-util-types').Tokenizer} Tokenizer
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*/
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import {push, splice} from 'micromark-util-chunked'
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import {classifyCharacter} from 'micromark-util-classify-character'
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import {resolveAll} from 'micromark-util-resolve-all'
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import {codes, constants, types} from 'micromark-util-symbol'
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import {ok as assert} from 'devlop'
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/** @type {Construct} */
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export const attention = {
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name: 'attention',
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tokenize: tokenizeAttention,
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resolveAll: resolveAllAttention
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}
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/**
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* Take all events and resolve attention to emphasis or strong.
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*
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* @type {Resolver}
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*/
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// eslint-disable-next-line complexity
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function resolveAllAttention(events, context) {
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let index = -1
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/** @type {number} */
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let open
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/** @type {Token} */
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let group
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/** @type {Token} */
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let text
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/** @type {Token} */
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let openingSequence
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/** @type {Token} */
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let closingSequence
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/** @type {number} */
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let use
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/** @type {Array<Event>} */
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let nextEvents
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/** @type {number} */
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let offset
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// Walk through all events.
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//
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// Note: performance of this is fine on an mb of normal markdown, but it’s
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// a bottleneck for malicious stuff.
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while (++index < events.length) {
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// Find a token that can close.
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if (
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events[index][0] === 'enter' &&
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events[index][1].type === 'attentionSequence' &&
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events[index][1]._close
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) {
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open = index
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// Now walk back to find an opener.
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while (open--) {
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// Find a token that can open the closer.
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if (
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events[open][0] === 'exit' &&
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events[open][1].type === 'attentionSequence' &&
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events[open][1]._open &&
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// If the markers are the same:
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context.sliceSerialize(events[open][1]).charCodeAt(0) ===
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context.sliceSerialize(events[index][1]).charCodeAt(0)
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) {
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// If the opening can close or the closing can open,
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// and the close size *is not* a multiple of three,
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// but the sum of the opening and closing size *is* multiple of three,
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// then don’t match.
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if (
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(events[open][1]._close || events[index][1]._open) &&
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(events[index][1].end.offset - events[index][1].start.offset) % 3 &&
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!(
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(events[open][1].end.offset -
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events[open][1].start.offset +
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events[index][1].end.offset -
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events[index][1].start.offset) %
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3
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)
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) {
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continue
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}
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// Number of markers to use from the sequence.
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use =
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events[open][1].end.offset - events[open][1].start.offset > 1 &&
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events[index][1].end.offset - events[index][1].start.offset > 1
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? 2
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: 1
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const start = Object.assign({}, events[open][1].end)
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const end = Object.assign({}, events[index][1].start)
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movePoint(start, -use)
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movePoint(end, use)
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openingSequence = {
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type: use > 1 ? types.strongSequence : types.emphasisSequence,
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start,
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end: Object.assign({}, events[open][1].end)
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}
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closingSequence = {
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type: use > 1 ? types.strongSequence : types.emphasisSequence,
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start: Object.assign({}, events[index][1].start),
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end
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}
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text = {
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type: use > 1 ? types.strongText : types.emphasisText,
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start: Object.assign({}, events[open][1].end),
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end: Object.assign({}, events[index][1].start)
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}
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group = {
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type: use > 1 ? types.strong : types.emphasis,
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start: Object.assign({}, openingSequence.start),
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end: Object.assign({}, closingSequence.end)
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}
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events[open][1].end = Object.assign({}, openingSequence.start)
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events[index][1].start = Object.assign({}, closingSequence.end)
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nextEvents = []
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// If there are more markers in the opening, add them before.
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if (events[open][1].end.offset - events[open][1].start.offset) {
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nextEvents = push(nextEvents, [
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['enter', events[open][1], context],
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['exit', events[open][1], context]
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])
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}
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// Opening.
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nextEvents = push(nextEvents, [
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['enter', group, context],
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['enter', openingSequence, context],
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['exit', openingSequence, context],
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['enter', text, context]
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])
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// Always populated by defaults.
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assert(
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context.parser.constructs.insideSpan.null,
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'expected `insideSpan` to be populated'
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)
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// Between.
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nextEvents = push(
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nextEvents,
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resolveAll(
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context.parser.constructs.insideSpan.null,
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events.slice(open + 1, index),
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context
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)
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)
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// Closing.
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nextEvents = push(nextEvents, [
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['exit', text, context],
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['enter', closingSequence, context],
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['exit', closingSequence, context],
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['exit', group, context]
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])
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// If there are more markers in the closing, add them after.
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if (events[index][1].end.offset - events[index][1].start.offset) {
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offset = 2
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nextEvents = push(nextEvents, [
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['enter', events[index][1], context],
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['exit', events[index][1], context]
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])
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} else {
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offset = 0
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}
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splice(events, open - 1, index - open + 3, nextEvents)
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index = open + nextEvents.length - offset - 2
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break
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}
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}
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}
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}
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// Remove remaining sequences.
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index = -1
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while (++index < events.length) {
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if (events[index][1].type === 'attentionSequence') {
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events[index][1].type = 'data'
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}
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}
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return events
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}
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/**
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* @this {TokenizeContext}
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* @type {Tokenizer}
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*/
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function tokenizeAttention(effects, ok) {
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const attentionMarkers = this.parser.constructs.attentionMarkers.null
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const previous = this.previous
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const before = classifyCharacter(previous)
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/** @type {NonNullable<Code>} */
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let marker
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return start
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/**
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* Before a sequence.
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*
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* ```markdown
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* > | **
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* ^
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* ```
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*
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* @type {State}
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*/
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function start(code) {
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assert(
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code === codes.asterisk || code === codes.underscore,
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'expected asterisk or underscore'
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)
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marker = code
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effects.enter('attentionSequence')
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return inside(code)
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}
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/**
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* In a sequence.
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*
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* ```markdown
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* > | **
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* ^^
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* ```
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*
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* @type {State}
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*/
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function inside(code) {
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if (code === marker) {
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effects.consume(code)
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return inside
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}
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const token = effects.exit('attentionSequence')
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// To do: next major: move this to resolver, just like `markdown-rs`.
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const after = classifyCharacter(code)
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// Always populated by defaults.
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assert(attentionMarkers, 'expected `attentionMarkers` to be populated')
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const open =
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!after ||
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(after === constants.characterGroupPunctuation && before) ||
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attentionMarkers.includes(code)
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const close =
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!before ||
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(before === constants.characterGroupPunctuation && after) ||
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attentionMarkers.includes(previous)
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token._open = Boolean(
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marker === codes.asterisk ? open : open && (before || !close)
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)
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token._close = Boolean(
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marker === codes.asterisk ? close : close && (after || !open)
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)
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return ok(code)
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}
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}
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/**
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* Move a point a bit.
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*
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* Note: `move` only works inside lines! It’s not possible to move past other
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* chunks (replacement characters, tabs, or line endings).
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*
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* @param {Point} point
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* @param {number} offset
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* @returns {undefined}
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*/
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function movePoint(point, offset) {
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point.column += offset
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point.offset += offset
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point._bufferIndex += offset
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}
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