89 lines
3.0 KiB
TypeScript
89 lines
3.0 KiB
TypeScript
/** Let asterisk strong emphasis close after punctuation when CJK prose continues without whitespace. */
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import { attention } from 'micromark-core-commonmark'
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import { unicodePunctuation } from 'micromark-util-character'
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import { classifyCharacter } from 'micromark-util-classify-character'
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import { codes, constants } from 'micromark-util-symbol'
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import type { Construct, Extension, State, Tokenizer } from 'micromark-util-types'
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interface RemarkProcessor {
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data(): { micromarkExtensions?: Extension[] }
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}
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const cjkCharacter = new RegExp([
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'\\p{Script_Extensions=Han}',
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'\\p{Script_Extensions=Hiragana}',
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'\\p{Script_Extensions=Katakana}',
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'\\p{Script_Extensions=Hangul}',
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'\\p{Script_Extensions=Bopomofo}',
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].join('|'), 'u')
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function isCjkCharacter(code: number | null): boolean {
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return code !== null && code >= 0 && cjkCharacter.test(String.fromCodePoint(code))
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}
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const tokenizeCjkFriendlyAttention: Tokenizer = function (effects, ok, nok) {
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const configuredAttentionMarkers = this.parser.constructs.attentionMarkers.null
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if (configuredAttentionMarkers === undefined) {
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throw new Error('micromark CommonMark attention markers are unavailable')
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}
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const attentionMarkers = configuredAttentionMarkers
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const previous = this.previous
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const before = classifyCharacter(previous)
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let marker: number | null = codes.eof
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return start
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function start(code: number | null): State | undefined {
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/* v8 ignore next -- this text construct is dispatched only for an asterisk. */
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if (code !== codes.asterisk) return nok(code)
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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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function inside(code: number | null): State | undefined {
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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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const after = classifyCharacter(code)
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const open = !after || (after === constants.characterGroupPunctuation && Boolean(before))
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|| attentionMarkers.includes(code)
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const commonMarkClose = !before
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|| (before === constants.characterGroupPunctuation && Boolean(after))
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|| attentionMarkers.includes(previous)
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const markerCount = token.end.offset - token.start.offset
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const cjkStrongClose = markerCount >= 2
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&& unicodePunctuation(previous)
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&& isCjkCharacter(code)
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const close = commonMarkClose || cjkStrongClose
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token._open = open
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token._close = close
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return ok(code)
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}
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}
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const cjkFriendlyAttention: Construct = {
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name: 'cjkFriendlyAttention',
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resolveAll: attention.resolveAll,
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tokenize: tokenizeCjkFriendlyAttention,
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}
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const cjkFriendlyStrong: Extension = {
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text: { [codes.asterisk]: cjkFriendlyAttention },
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}
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/**
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* Extend CommonMark asterisk strong emphasis for punctuation-delimited CJK prose.
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* @returns Nothing.
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*/
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export function remarkCjkFriendlyStrong(this: RemarkProcessor): undefined {
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const data = this.data()
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const extensions = data.micromarkExtensions ?? (data.micromarkExtensions = [])
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extensions.push(cjkFriendlyStrong)
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}
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