340 lines
16 KiB
TypeScript
340 lines
16 KiB
TypeScript
import type { AttributeKind, VocabularyPair, VocabularyValue } from '../adf/attribute-vocabulary.ts'
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import type { ConvertFault } from '../result.ts'
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import type { JsonValue } from '../json-value.ts'
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import { backslashEscape } from './commonmark/grammar.ts'
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import { backtickRun, closingBacktickRun } from './commonmark/backtick-runs.ts'
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import { isJsonValue, overNested } from '../json-value.ts'
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import { largestNesting } from '../nesting.ts'
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import { serializeCanonicalJson } from '../canonical-json.ts'
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export type AttributeReading = { refusal: 'kind' | 'nesting'; value?: undefined } | { refusal?: undefined; value: VocabularyValue }
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export type DirectiveValue = { decoded: string; spelling: string }
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export type DirectiveAttributes = ReadonlyMap<string, DirectiveValue>
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export type DirectiveLine =
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| { argument: string | undefined; attributes: DirectiveAttributes; kind: 'opener'; name: string }
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| { kind: 'closer'; name: string }
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// spans keys index content, so the two travel together: separate them and every offset is wrong.
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export type DirectiveSpan = { attributes: DirectiveAttributes; content: string | undefined; length: number; name: string; spans: NestedSpans }
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export type NestedSpans = ReadonlyMap<number, DirectiveSpan>
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export type Read<T> = { fault: ConvertFault; value?: undefined } | { fault?: undefined; value: T }
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type Attributes = { attributes: DirectiveAttributes; end: number }
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type AttributePair = { end: number; key: string; value: DirectiveValue }
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type Content = { content: string | undefined; end: number; spans: NestedSpans }
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type DirectiveContent = { end: number; spans: NestedSpans }
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export const directivePrefix = '!adf:'
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const bareTokenSource = '[A-Za-z0-9_-]+'
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const bareRun = new RegExp(bareTokenSource, 'y')
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const bareToken = new RegExp(`^${bareTokenSource}$`)
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const directiveName = /[a-z][A-Za-z0-9]*/y
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const inlineDirectiveOpener = new RegExp(`${directivePrefix}[a-z][A-Za-z0-9]*[[{]`, 'y')
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const lineEnd = /^[ \t]*$/
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// spec/flavour.md, Attributes.
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const reservedSource = '[&<`|]'
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const quotedEscapes = new RegExp(reservedSource, 'g')
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const rawReserved = new RegExp(reservedSource)
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const noAttributes: DirectiveAttributes = new Map()
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export const noSpans: NestedSpans = new Map()
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export const directiveEscape = `\\${directivePrefix} keeps the prefix literal`
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const closerFault = `a closer carries nothing after its name: this one does; ${directiveEscape}`
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const emptyFault = 'an empty {attrs} is omitted unless the { itself claims the directive: this one spells {}'
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const openerFault = `a directive opener reads a name, one bare argument and {attrs}, one space apart: this one does not; ${directiveEscape}`
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const orderFault = 'the {attrs} keys read in alphabetical order'
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const pairFault = `an attribute reads key=value, the value bare or double-quoted: this one does not; ${directiveEscape}`
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const prefixFault = `an unescaped ${directivePrefix} completes no directive; ${directiveEscape}`
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export function attributeValue(text: string, kind: AttributeKind): AttributeReading {
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if (kind === 'string') return { value: { kind, value: text } }
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if (kind === 'boolean') return text === 'true' || text === 'false' ? { value: { kind, value: text === 'true' } } : { refusal: 'kind' }
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const parsed = parseJson(text)
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if (parsed === undefined) return { refusal: 'kind' }
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if (kind === 'number') return typeof parsed === 'number' ? { value: { kind, value: parsed } } : { refusal: 'kind' }
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return overNested(parsed) ? { refusal: 'nesting' } : { value: { kind, value: parsed } }
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}
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export function claimsDirectivePrefix(text: string, index: number): boolean {
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return text.startsWith(directivePrefix, index)
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}
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export function holdsDirectivePrefix(text: string): boolean {
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return text.includes(directivePrefix)
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}
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export function isBareToken(text: string): boolean {
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return bareToken.test(text)
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}
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export function malformedDirective(message: string): ConvertFault {
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return { code: 'malformed-directive', message }
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}
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export function readDirectiveLine(line: string): Read<DirectiveLine> | undefined {
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if (!claimsDirectivePrefix(line, 0)) return undefined
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return line.charAt(directivePrefix.length) === '/' ? readCloserLine(line) : readOpenerLine(line)
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}
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export function readInlineDirective(text: string, index: number): Read<DirectiveSpan> | undefined {
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return readNestedDirective(text, index, 1)
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}
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export function readSoleStringAttribute(span: DirectiveSpan, key: string): Read<string> {
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if (span.content !== undefined) return { fault: unsupportedNodeShape(`${span.name} takes no content: this one holds some`) }
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const spelled = span.attributes.get(key)
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if (spelled === undefined || span.attributes.size !== 1) return { fault: unsupportedNodeShape(`${span.name} holds one ${key} attribute alone: this one does not`) }
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const spelling = spellStringAttribute(spelled.decoded)
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if (spelling !== spelled.spelling) return { fault: unsupportedNodeShape(`${span.name} spells its ${key} attribute as ${key}=${spelling}`) }
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return { value: spelled.decoded }
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}
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// Both directions answer alike: an inline directive never spans lines, so no content slot holds a line ending.
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export function slotLineEndingFault(type: string, text: string): ConvertFault | undefined {
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if (!/[\n\r]/.test(text)) return undefined
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return { code: 'unspellable-whitespace', message: `the ${type} content slot holds a newline no inline directive spans` }
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}
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export function spellAttributes(pairs: readonly (readonly [string, string])[]): string {
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if (pairs.length === 0) return ''
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const spelled = [...pairs].sort(([left], [right]) => keyOrder(left, right)).map(([key, value]) => `${key}=${value}`)
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return `{${spelled.join(' ')}}`
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}
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export function spellDirectiveCloser(name: string): string {
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return `${directivePrefix}/${name}`
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}
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export function spellDirectiveOpener(name: string, argument: string | undefined, attributes: string): string {
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return `${directivePrefix}${name}${argument === undefined ? '' : ` ${argument}`}${attributes === '' ? '' : ` ${attributes}`}`
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}
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export function spellJsonAttribute(value: JsonValue): string {
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return quote(serializeCanonicalJson(value, 'compact'))
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}
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export function spellInlineDirectiveOpener(name: string): string {
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return `${directivePrefix}${name}[`
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}
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export function spellInlineLeafDirective(name: string, attributes: string): string {
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return `${directivePrefix}${name}${attributes === '' ? '{}' : attributes}`
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}
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export function spellStringAttribute(text: string): string {
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return isBareToken(text) ? text : quote(text)
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}
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export function spellAttributeValue(value: VocabularyValue): string {
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if (value.kind === 'boolean') return `${value.value}`
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if (value.kind === 'json') return spellJsonAttribute(value.value)
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if (value.kind === 'number') return spellStringAttribute(JSON.stringify(value.value))
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return spellStringAttribute(value.value)
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}
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export function spellVocabulary(pairs: readonly VocabularyPair[]): [string, string][] {
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return pairs.map((pair): [string, string] => [pair.key, spellAttributeValue(pair)])
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}
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export function unknownDirectiveFault(name: string): ConvertFault {
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return { code: 'unknown-directive-name', message: `the directive name ${name} reads back to no node; ${directiveEscape}` }
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}
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export function unsupportedNodeShape(message: string): ConvertFault {
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return { code: 'unsupported-node-shape', message }
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}
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function keyOrder(left: string, right: string): number {
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if (left < right) return -1
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return left > right ? 1 : 0
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}
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function quote(text: string): string {
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return JSON.stringify(text).replace(quotedEscapes, (character) => `\\u${escapeDigits(character)}`)
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}
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function escapeDigits(character: string): string {
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return character.charCodeAt(0).toString(16).padStart(4, '0')
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}
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function inlineDirectiveName(text: string, index: number): string | undefined {
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inlineDirectiveOpener.lastIndex = index
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const opened = inlineDirectiveOpener.exec(text)?.[0]
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return opened === undefined ? undefined : opened.slice(directivePrefix.length, -1)
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}
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function readCloserLine(line: string): Read<DirectiveLine> | undefined {
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const start = directivePrefix.length + 1
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const name = readDirectiveName(line, start)
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if (name === undefined) return undefined
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return lineEnd.test(line.slice(start + name.length)) ? { value: { kind: 'closer', name } } : { fault: malformedDirective(closerFault) }
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}
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function readOpenerLine(line: string): Read<DirectiveLine> | undefined {
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const name = readDirectiveName(line, directivePrefix.length)
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if (name === undefined) return undefined
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const rest = line.slice(directivePrefix.length + name.length)
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if (!rest.startsWith(' ') && !lineEnd.test(rest)) return undefined
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const opener = readOpenerRest(rest)
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if (opener.fault !== undefined) return { fault: opener.fault }
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return { value: { argument: opener.value.argument, attributes: opener.value.attributes, kind: 'opener', name } }
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}
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function readDirectiveName(text: string, index: number): string | undefined {
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directiveName.lastIndex = index
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return directiveName.exec(text)?.[0]
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}
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function readOpenerRest(rest: string): Read<{ argument: string | undefined; attributes: DirectiveAttributes }> {
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bareRun.lastIndex = 1
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const argument = bareRun.exec(rest)?.[0]
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const attributes = readOpenerAttributes(rest, argument === undefined ? 0 : 1 + argument.length)
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if (attributes.fault !== undefined) return { fault: attributes.fault }
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if (!lineEnd.test(rest.slice(attributes.value.end))) return { fault: malformedDirective(openerFault) }
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return { value: { argument, attributes: attributes.value.attributes } }
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}
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function readOpenerAttributes(rest: string, index: number): Read<Attributes> {
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return rest.charAt(index) === ' ' ? readAttributesAt(rest, index + 1, false) : { value: { attributes: noAttributes, end: index } }
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}
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function readNestedDirective(text: string, index: number, depth: number): Read<DirectiveSpan> | undefined {
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if (!claimsDirectivePrefix(text, index)) return undefined
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const name = inlineDirectiveName(text, index)
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if (name === undefined) return { fault: malformedDirective(prefixFault) }
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if (depth > largestNesting) {
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return { fault: { code: 'unsupported-nesting-depth', message: `the input nests inline directives deeper than the ${largestNesting} levels the parser carries` } }
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}
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const slot = readContentSlot(text, index + directivePrefix.length + name.length, depth)
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if (slot.fault !== undefined) return { fault: slot.fault }
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const attributes = readAttributesAt(text, slot.value.end, slot.value.content === undefined)
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if (attributes.fault !== undefined) return { fault: attributes.fault }
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return { value: { attributes: attributes.value.attributes, content: slot.value.content, length: attributes.value.end - index, name, spans: slot.value.spans } }
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}
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function readContentSlot(text: string, index: number, depth: number): Read<Content> {
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if (text.charAt(index) !== '[') return { value: { content: undefined, end: index, spans: noSpans } }
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const close = readDirectiveContent(text, index + 1, depth)
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if (close.fault !== undefined) return { fault: close.fault }
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return { value: { content: text.slice(index + 1, close.value.end), end: close.value.end + 1, spans: close.value.spans } }
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}
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function readAttributesAt(text: string, index: number, braceClaims: boolean): Read<Attributes> {
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if (text.charAt(index) !== '{') return { value: { attributes: noAttributes, end: index } }
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const read = readAttributes(text, index)
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if (read.fault !== undefined || braceClaims || read.value.attributes.size > 0) return read
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return { fault: malformedDirective(emptyFault) }
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}
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// A code span, an escape and a nested directive each bind before the content's own closing bracket.
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function readDirectiveContent(text: string, start: number, depth: number): Read<DirectiveContent> {
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const spans = new Map<number, DirectiveSpan>()
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let brackets = 0
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let cursor = start
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while (cursor < text.length && text.charAt(cursor) !== '\n') {
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const character = text.charAt(cursor)
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if (character === '\\') {
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cursor += backslashEscape(text, cursor) === undefined ? 1 : 2
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continue
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}
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if (character === '`') {
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const span = readCodeSpanEnd(text, cursor)
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if (span === undefined) break
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cursor = span
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continue
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}
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const nested = readNestedDirective(text, cursor, depth + 1)
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if (nested?.fault !== undefined) return { fault: nested.fault }
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if (nested !== undefined) {
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spans.set(cursor - start, nested.value)
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cursor += nested.value.length
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continue
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}
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if (character === ']' && brackets === 0) return { value: { end: cursor, spans } }
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if (character === '[') brackets += 1
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if (character === ']') brackets -= 1
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cursor += 1
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}
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return { fault: malformedDirective(`an inline directive [content] is unclosed; ${directiveEscape}`) }
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}
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// `undefined` where the span crosses the line ending an inline directive may not cross.
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function readCodeSpanEnd(text: string, index: number): number | undefined {
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const opener = backtickRun(text, index)
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const closer = closingBacktickRun(text, index + opener, opener)
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if (closer === undefined) return index + opener
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return text.slice(index, closer + opener).includes('\n') ? undefined : closer + opener
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}
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function readAttributes(text: string, index: number): Read<Attributes> {
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const attributes = new Map<string, DirectiveValue>()
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let cursor = index + 1
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let previous = ''
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while (cursor < text.length && text.charAt(cursor) !== '}') {
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if (attributes.size > 0) {
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if (text.charAt(cursor) !== ' ') return { fault: malformedDirective(pairFault) }
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cursor += 1
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}
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const pair = readAttributePair(text, cursor)
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if (pair.fault !== undefined) return { fault: pair.fault }
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const key = pair.value.key
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if (attributes.has(key)) return { fault: malformedDirective(`the attribute key ${key} is spelled twice`) }
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if (keyOrder(previous, key) > 0) return { fault: malformedDirective(`${orderFault}: ${key} before ${previous}`) }
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previous = key
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attributes.set(key, pair.value.value)
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cursor = pair.value.end
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}
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if (text.charAt(cursor) !== '}') return { fault: malformedDirective('the {attrs} closing brace is missing') }
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return { value: { attributes, end: cursor + 1 } }
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}
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function readAttributePair(text: string, index: number): Read<AttributePair> {
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bareRun.lastIndex = index
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const key = bareRun.exec(text)?.[0]
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if (key === undefined || text.charAt(index + key.length) !== '=') return { fault: malformedDirective(pairFault) }
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const start = index + key.length + 1
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if (text.charAt(start) === '"') {
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const quoted = readQuotedValue(text, start)
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if (quoted.fault !== undefined) return { fault: quoted.fault }
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return { value: { end: quoted.value.end, key, value: quoted.value.value } }
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}
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bareRun.lastIndex = start
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const bare = bareRun.exec(text)?.[0]
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if (bare === undefined) return { fault: malformedDirective(pairFault) }
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return { value: { end: start + bare.length, key, value: { decoded: bare, spelling: bare } } }
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}
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function readQuotedValue(text: string, index: number): Read<{ end: number; value: DirectiveValue }> {
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let cursor = index + 1
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while (cursor < text.length && text.charAt(cursor) !== '"') cursor += text.charAt(cursor) === '\\' ? 2 : 1
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if (text.charAt(cursor) !== '"') return { fault: malformedDirective('the {attrs} quoted value is unclosed') }
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const spelling = text.slice(index, cursor + 1)
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const character = rawReserved.exec(spelling)?.[0]
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if (character !== undefined) {
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return { fault: malformedDirective(`a raw ${character} inside {attrs} breaks the directive: spell it \\u${escapeDigits(character)}`) }
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}
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const parsed = parseJson(spelling)
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if (typeof parsed !== 'string') return { fault: malformedDirective('the {attrs} quoted value is not a JSON string') }
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return { value: { end: cursor + 1, value: { decoded: parsed, spelling } } }
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}
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function parseJson(raw: string): JsonValue | undefined {
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try {
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const value: unknown = JSON.parse(raw)
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return isJsonValue(value) ? value : undefined
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} catch {
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return undefined
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}
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}
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