595 lines
21 KiB
JavaScript
595 lines
21 KiB
JavaScript
// WARNING: This file was ported from json_schema_to_grammar.py, please fix bugs / add features there first.
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const SPACE_RULE = '" "?';
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function _buildRepetition(itemRule, minItems, maxItems, opts={}) {
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const separatorRule = opts.separatorRule ?? '';
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const itemRuleIsLiteral = opts.itemRuleIsLiteral ?? false
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if (separatorRule === '') {
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if (minItems === 0 && maxItems === 1) {
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return `${itemRule}?`;
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} else if (minItems === 1 && maxItems === undefined) {
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return `${itemRule}+`;
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}
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}
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let result = '';
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if (minItems > 0) {
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if (itemRuleIsLiteral && separatorRule === '') {
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result = `"${itemRule.slice(1, -1).repeat(minItems)}"`;
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} else {
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result = Array.from({ length: minItems }, () => itemRule)
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.join(separatorRule !== '' ? ` ${separatorRule} ` : ' ');
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}
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}
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const optRepetitions = (upToN, prefixWithSep=false) => {
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const content = separatorRule !== '' && prefixWithSep ? `${separatorRule} ${itemRule}` : itemRule;
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if (upToN === 0) {
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return '';
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} else if (upToN === 1) {
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return `(${content})?`;
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} else if (separatorRule !== '' && !prefixWithSep) {
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return `(${content} ${optRepetitions(upToN - 1, true)})?`;
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} else {
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return Array.from({ length: upToN }, () => `(${content}`).join(' ').trim() + Array.from({ length: upToN }, () => ')?').join('');
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}
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};
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if (minItems > 0 && maxItems !== minItems) {
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result += ' ';
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}
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if (maxItems !== undefined) {
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result += optRepetitions(maxItems - minItems, minItems > 0);
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} else {
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const itemOperator = `(${separatorRule !== '' ? separatorRule + ' ' : ''}${itemRule})`;
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if (minItems === 0 && separatorRule !== '') {
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result = `(${itemRule} ${itemOperator}*)?`;
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} else {
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result += `${itemOperator}*`;
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}
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}
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return result;
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}
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class BuiltinRule {
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constructor(content, deps) {
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this.content = content;
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this.deps = deps || [];
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}
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}
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const UP_TO_15_DIGITS = _buildRepetition('[0-9]', 0, 15);
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const PRIMITIVE_RULES = {
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boolean : new BuiltinRule('("true" | "false") space', []),
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'decimal-part' : new BuiltinRule('[0-9] ' + UP_TO_15_DIGITS, []),
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'integral-part': new BuiltinRule('[0-9] | [1-9] ' + UP_TO_15_DIGITS, []),
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number : new BuiltinRule('("-"? integral-part) ("." decimal-part)? ([eE] [-+]? integral-part)? space', ['integral-part', 'decimal-part']),
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integer : new BuiltinRule('("-"? integral-part) space', ['integral-part']),
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value : new BuiltinRule('object | array | string | number | boolean | null', ['object', 'array', 'string', 'number', 'boolean', 'null']),
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object : new BuiltinRule('"{" space ( string ":" space value ("," space string ":" space value)* )? "}" space', ['string', 'value']),
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array : new BuiltinRule('"[" space ( value ("," space value)* )? "]" space', ['value']),
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uuid : new BuiltinRule('"\\"" ' + [8, 4, 4, 4, 12].map(n => [...new Array(n)].map(_ => '[0-9a-fA-F]').join('')).join(' "-" ') + ' "\\"" space', []),
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char : new BuiltinRule(`[^"\\\\] | "\\\\" (["\\\\/bfnrt] | "u" [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F])`, []),
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string : new BuiltinRule(`"\\"" char* "\\"" space`, ['char']),
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null : new BuiltinRule('"null" space', []),
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};
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// TODO: support "uri", "email" string formats
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const STRING_FORMAT_RULES = {
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'date' : new BuiltinRule('[0-9] [0-9] [0-9] [0-9] "-" ( "0" [1-9] | "1" [0-2] ) "-" ( \"0\" [1-9] | [1-2] [0-9] | "3" [0-1] )', []),
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'time' : new BuiltinRule('([01] [0-9] | "2" [0-3]) ":" [0-5] [0-9] ":" [0-5] [0-9] ( "." [0-9] [0-9] [0-9] )? ( "Z" | ( "+" | "-" ) ( [01] [0-9] | "2" [0-3] ) ":" [0-5] [0-9] )', []),
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'date-time' : new BuiltinRule('date "T" time', ['date', 'time']),
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'date-string' : new BuiltinRule('"\\"" date "\\"" space', ['date']),
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'time-string' : new BuiltinRule('"\\"" time "\\"" space', ['time']),
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'date-time-string': new BuiltinRule('"\\"" date-time "\\"" space', ['date-time']),
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}
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const RESERVED_NAMES = {'root': true, ...PRIMITIVE_RULES, ...STRING_FORMAT_RULES};
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const INVALID_RULE_CHARS_RE = /[^\dA-Za-z-]+/g;
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const GRAMMAR_LITERAL_ESCAPE_RE = /[\n\r"]/g;
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const GRAMMAR_RANGE_LITERAL_ESCAPE_RE = /[\n\r"\]\-\\]/g;
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const GRAMMAR_LITERAL_ESCAPES = { '\r': '\\r', '\n': '\\n', '"': '\\"', '-': '\\-', ']': '\\]' };
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const NON_LITERAL_SET = new Set('|.()[]{}*+?');
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const ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS = new Set('[]()|{}*+?');
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export class SchemaConverter {
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constructor(options) {
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this._propOrder = options.prop_order || {};
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this._allowFetch = options.allow_fetch || false;
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this._dotall = options.dotall || false;
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this._rules = {'space': SPACE_RULE};
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this._refs = {};
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this._refsBeingResolved = new Set();
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}
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_formatLiteral(literal) {
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const escaped = literal.replace(
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GRAMMAR_LITERAL_ESCAPE_RE,
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m => GRAMMAR_LITERAL_ESCAPES[m]
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);
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return `"${escaped}"`;
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}
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_formatRangeChar(literal) {
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return JSON.stringify(literal).slice(1, -1).replace(
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GRAMMAR_RANGE_LITERAL_ESCAPE_RE,
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m => GRAMMAR_LITERAL_ESCAPES[m]
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);
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}
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_addRule(name, rule) {
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let escName = name.replace(INVALID_RULE_CHARS_RE, '-');
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let key = escName;
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if (escName in this._rules) {
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if (this._rules[escName] === rule) {
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return key;
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}
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let i = 0;
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while ((`${escName}${i}` in this._rules) && (this._rules[`${escName}${i}`] !== rule)) {
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i += 1;
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}
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key = `${escName}${i}`;
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}
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this._rules[key] = rule;
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return key;
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}
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async resolveRefs(schema, url) {
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const visit = async (n) => {
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if (Array.isArray(n)) {
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return Promise.all(n.map(visit));
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} else if (typeof n === 'object' && n !== null) {
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let ref = n.$ref;
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let target;
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if (ref !== undefined && !this._refs[ref]) {
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if (ref.startsWith('https://')) {
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if (!this._allowFetch) {
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throw new Error('Fetching remote schemas is not allowed (use --allow-fetch for force)');
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}
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const fetch = (await import('node-fetch')).default;
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const fragSplit = ref.split('#');
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const baseUrl = fragSplit[0];
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target = this._refs[baseUrl];
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if (!target) {
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target = await this.resolveRefs(await fetch(ref).then(res => res.json()), baseUrl);
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this._refs[baseUrl] = target;
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}
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if (fragSplit.length === 1 || fragSplit[fragSplit.length - 1] === '') {
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return target;
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}
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} else if (ref.startsWith('#/')) {
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target = schema;
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ref = `${url}${ref}`;
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n.$ref = ref;
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} else {
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throw new Error(`Unsupported ref ${ref}`);
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}
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const selectors = ref.split('#')[1].split('/').slice(1);
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for (const sel of selectors) {
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if (!target || !(sel in target)) {
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throw new Error(`Error resolving ref ${ref}: ${sel} not in ${JSON.stringify(target)}`);
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}
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target = target[sel];
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}
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this._refs[ref] = target;
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} else {
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await Promise.all(Object.values(n).map(visit));
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}
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}
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return n;
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};
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return visit(schema);
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}
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_generateUnionRule(name, altSchemas) {
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return altSchemas
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.map((altSchema, i) => this.visit(altSchema, `${name ?? ''}${name ? '-' : 'alternative-'}${i}`))
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.join(' | ');
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}
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_visitPattern(pattern, name) {
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if (!pattern.startsWith('^') || !pattern.endsWith('$')) {
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throw new Error('Pattern must start with "^" and end with "$"');
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}
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pattern = pattern.slice(1, -1);
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const subRuleIds = {};
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let i = 0;
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const length = pattern.length;
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const getDot = () => {
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let rule;
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if (this._dotall) {
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rule = '[\\U00000000-\\U0010FFFF]';
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} else {
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// Accept any character... except \n and \r line break chars (\x0A and \xOD)
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rule = '[^\\x0A\\x0D]';
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}
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return this._addRule('dot', rule);
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};
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const toRule = ([s, isLiteral]) => isLiteral ? "\"" + s + "\"" : s;
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const transform = () => {
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const start = i;
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// For each component of this sequence, store its string representation and whether it's a literal.
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// We only need a flat structure here to apply repetition operators to the last item, and
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// to merge literals at the and (we're parsing grouped ( sequences ) recursively and don't treat '|' specially
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// (GBNF's syntax is luckily very close to regular expressions!)
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const seq = [];
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const joinSeq = () => {
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const ret = [];
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for (const [isLiteral, g] of groupBy(seq, x => x[1])) {
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if (isLiteral) {
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ret.push([[...g].map(x => x[0]).join(''), true]);
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} else {
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ret.push(...g);
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}
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}
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if (ret.length === 1) {
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return ret[0];
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}
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return [ret.map(x => toRule(x)).join(' '), false];
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};
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while (i < length) {
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const c = pattern[i];
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if (c === '.') {
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seq.push([getDot(), false]);
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i += 1;
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} else if (c === '(') {
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i += 1;
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if (i < length) {
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if (pattern[i] === '?') {
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throw new Error(`Unsupported pattern syntax "${pattern[i]}" at index ${i} of /${pattern}/`);
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}
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}
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seq.push([`(${toRule(transform())})`, false]);
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} else if (c === ')') {
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i += 1;
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if (start <= 0 || pattern[start - 1] !== '(') {
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throw new Error(`Unbalanced parentheses; start = ${start}, i = ${i}, pattern = ${pattern}`);
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}
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return joinSeq();
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} else if (c === '[') {
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let squareBrackets = c;
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i += 1;
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while (i < length && pattern[i] !== ']') {
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if (pattern[i] === '\\') {
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squareBrackets += pattern.slice(i, i + 2);
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i += 2;
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} else {
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squareBrackets += pattern[i];
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i += 1;
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}
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}
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if (i >= length) {
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throw new Error(`Unbalanced square brackets; start = ${start}, i = ${i}, pattern = ${pattern}`);
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}
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squareBrackets += ']';
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i += 1;
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seq.push([squareBrackets, false]);
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} else if (c === '|') {
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seq.push(['|', false]);
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i += 1;
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} else if (c === '*' || c === '+' || c === '?') {
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seq[seq.length - 1] = [toRule(seq[seq.length - 1]) + c, false];
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i += 1;
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} else if (c === '{') {
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let curlyBrackets = c;
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i += 1;
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while (i < length && pattern[i] !== '}') {
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curlyBrackets += pattern[i];
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i += 1;
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}
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if (i >= length) {
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throw new Error(`Unbalanced curly brackets; start = ${start}, i = ${i}, pattern = ${pattern}`);
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}
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curlyBrackets += '}';
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i += 1;
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const nums = curlyBrackets.slice(1, -1).split(',').map(s => s.trim());
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let minTimes, maxTimes;
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if (nums.length === 1) {
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minTimes = parseInt(nums[0], 10);
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maxTimes = minTimes;
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} else {
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if (nums.length !== 2) {
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throw new Error(`Invalid quantifier ${curlyBrackets}`);
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}
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minTimes = nums[0] ? parseInt(nums[0], 10) : 0;
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maxTimes = nums[1] ? parseInt(nums[1], 10) : Infinity;
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}
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let [sub, subIsLiteral] = seq[seq.length - 1];
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if (!subIsLiteral) {
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let id = subRuleIds[sub];
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if (id === undefined) {
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id = this._addRule(`${name}-${Object.keys(subRuleIds).length + 1}`, sub);
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subRuleIds[sub] = id;
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}
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sub = id;
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}
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seq[seq.length - 1] = [
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_buildRepetition(subIsLiteral ? `"${sub}"` : sub, minTimes, maxTimes, {itemRuleIsLiteral: subIsLiteral}),
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false
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];
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} else {
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let literal = '';
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while (i < length) {
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if (pattern[i] === '\\' && i < length - 1) {
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const next = pattern[i + 1];
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if (ESCAPED_IN_REGEXPS_BUT_NOT_IN_LITERALS.has(next)) {
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i += 1;
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literal += pattern[i];
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i += 1;
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} else {
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literal += pattern.slice(i, i + 2);
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i += 2;
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}
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} else if (pattern[i] === '"') {
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literal += '\\"';
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i += 1;
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} else if (!NON_LITERAL_SET.has(pattern[i]) &&
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(i === length - 1 || literal === '' || pattern[i + 1] === '.' || !NON_LITERAL_SET.has(pattern[i+1]))) {
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literal += pattern[i];
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i += 1;
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} else {
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break;
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}
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}
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if (literal !== '') {
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seq.push([literal, true]);
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}
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}
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}
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return joinSeq();
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};
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return this._addRule(name, "\"\\\"\" " + toRule(transform()) + " \"\\\"\" space")
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}
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_resolveRef(ref) {
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let refName = ref.split('/').pop();
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if (!(refName in this._rules) && !this._refsBeingResolved.has(ref)) {
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this._refsBeingResolved.add(ref);
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const resolved = this._refs[ref];
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refName = this.visit(resolved, refName);
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this._refsBeingResolved.delete(ref);
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}
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return refName;
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}
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_generateConstantRule(value) {
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return this._formatLiteral(JSON.stringify(value));
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}
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visit(schema, name) {
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const schemaType = schema.type;
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const schemaFormat = schema.format;
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const ruleName = name in RESERVED_NAMES ? name + '-' : name == '' ? 'root' : name;
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const ref = schema.$ref;
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if (ref !== undefined) {
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return this._addRule(ruleName, this._resolveRef(ref));
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} else if (schema.oneOf || schema.anyOf) {
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return this._addRule(ruleName, this._generateUnionRule(name, schema.oneOf || schema.anyOf));
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} else if (Array.isArray(schemaType)) {
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return this._addRule(ruleName, this._generateUnionRule(name, schemaType.map(t => ({ type: t }))));
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} else if ('const' in schema) {
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return this._addRule(ruleName, this._generateConstantRule(schema.const));
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} else if ('enum' in schema) {
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const rule = schema.enum.map(v => this._generateConstantRule(v)).join(' | ');
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return this._addRule(ruleName, rule);
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} else if ((schemaType === undefined || schemaType === 'object') &&
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('properties' in schema ||
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('additionalProperties' in schema && schema.additionalProperties !== true))) {
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const required = new Set(schema.required || []);
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const properties = Object.entries(schema.properties ?? {});
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return this._addRule(ruleName, this._buildObjectRule(properties, required, name, schema.additionalProperties));
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} else if ((schemaType === undefined || schemaType === 'object') && 'allOf' in schema) {
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const required = new Set();
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const properties = [];
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const addComponent = (compSchema, isRequired) => {
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const ref = compSchema.$ref;
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if (ref !== undefined) {
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compSchema = this._refs[ref];
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}
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if ('properties' in compSchema) {
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for (const [propName, propSchema] of Object.entries(compSchema.properties)) {
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properties.push([propName, propSchema]);
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if (isRequired) {
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required.add(propName);
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}
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}
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}
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};
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for (const t of schema.allOf) {
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if ('anyOf' in t) {
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for (const tt of t.anyOf) {
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addComponent(tt, false);
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}
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} else {
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addComponent(t, true);
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}
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}
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return this._addRule(ruleName, this._buildObjectRule(properties, required, name, /* additionalProperties= */ false));
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} else if ((schemaType === undefined || schemaType === 'array') && ('items' in schema || 'prefixItems' in schema)) {
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const items = schema.items ?? schema.prefixItems;
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if (Array.isArray(items)) {
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return this._addRule(
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ruleName,
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'"[" space ' +
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items.map((item, i) => this.visit(item, `${name ?? ''}${name ? '-' : ''}tuple-${i}`)).join(' "," space ') +
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' "]" space'
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);
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} else {
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const itemRuleName = this.visit(items, `${name ?? ''}${name ? '-' : ''}item`);
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const minItems = schema.minItems || 0;
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const maxItems = schema.maxItems;
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return this._addRule(ruleName, '"[" space ' + _buildRepetition(itemRuleName, minItems, maxItems, {separatorRule: '"," space'}) + ' "]" space');
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}
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} else if ((schemaType === undefined || schemaType === 'string') && 'pattern' in schema) {
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return this._visitPattern(schema.pattern, ruleName);
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} else if ((schemaType === undefined || schemaType === 'string') && /^uuid[1-5]?$/.test(schema.format || '')) {
|
|
return this._addPrimitive(
|
|
ruleName === 'root' ? 'root' : schemaFormat,
|
|
PRIMITIVE_RULES['uuid']
|
|
);
|
|
} else if ((schemaType === undefined || schemaType === 'string') && `${schema.format}-string` in STRING_FORMAT_RULES) {
|
|
const primName = `${schema.format}-string`
|
|
return this._addRule(ruleName, this._addPrimitive(primName, STRING_FORMAT_RULES[primName]));
|
|
} else if (schemaType === 'string' && ('minLength' in schema || 'maxLength' in schema)) {
|
|
const charRuleName = this._addPrimitive('char', PRIMITIVE_RULES['char']);
|
|
const minLen = schema.minLength || 0;
|
|
const maxLen = schema.maxLength;
|
|
return this._addRule(ruleName, '"\\\"" ' + _buildRepetition(charRuleName, minLen, maxLen) + ' "\\\"" space');
|
|
} else if ((schemaType === 'object') || (Object.keys(schema).length === 0)) {
|
|
return this._addRule(ruleName, this._addPrimitive('object', PRIMITIVE_RULES['object']));
|
|
} else {
|
|
if (!(schemaType in PRIMITIVE_RULES)) {
|
|
throw new Error(`Unrecognized schema: ${JSON.stringify(schema)}`);
|
|
}
|
|
// TODO: support minimum, maximum, exclusiveMinimum, exclusiveMaximum at least for zero
|
|
return this._addPrimitive(ruleName === 'root' ? 'root' : schemaType, PRIMITIVE_RULES[schemaType]);
|
|
}
|
|
}
|
|
|
|
_addPrimitive(name, rule) {
|
|
let n = this._addRule(name, rule.content);
|
|
for (const dep of rule.deps) {
|
|
const depRule = PRIMITIVE_RULES[dep] || STRING_FORMAT_RULES[dep];
|
|
if (!depRule) {
|
|
throw new Error(`Rule ${dep} not known`);
|
|
}
|
|
if (!(dep in this._rules)) {
|
|
this._addPrimitive(dep, depRule);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
_buildObjectRule(properties, required, name, additionalProperties) {
|
|
const propOrder = this._propOrder;
|
|
// sort by position in prop_order (if specified) then by original order
|
|
const sortedProps = properties.map(([k]) => k).sort((a, b) => {
|
|
const orderA = propOrder[a] || Infinity;
|
|
const orderB = propOrder[b] || Infinity;
|
|
return orderA - orderB || properties.findIndex(([k]) => k === a) - properties.findIndex(([k]) => k === b);
|
|
});
|
|
|
|
const propKvRuleNames = {};
|
|
for (const [propName, propSchema] of properties) {
|
|
const propRuleName = this.visit(propSchema, `${name ?? ''}${name ? '-' : ''}${propName}`);
|
|
propKvRuleNames[propName] = this._addRule(
|
|
`${name ?? ''}${name ? '-' : ''}${propName}-kv`,
|
|
`${this._formatLiteral(JSON.stringify(propName))} space ":" space ${propRuleName}`
|
|
);
|
|
}
|
|
const requiredProps = sortedProps.filter(k => required.has(k));
|
|
const optionalProps = sortedProps.filter(k => !required.has(k));
|
|
|
|
if (typeof additionalProperties === 'object' || additionalProperties === true) {
|
|
const subName = `${name ?? ''}${name ? '-' : ''}additional`;
|
|
const valueRule = this.visit(additionalProperties === true ? {} : additionalProperties, `${subName}-value`);
|
|
propKvRuleNames['*'] = this._addRule(
|
|
`${subName}-kv`,
|
|
`${this._addPrimitive('string', PRIMITIVE_RULES['string'])} ":" space ${valueRule}`);
|
|
optionalProps.push('*');
|
|
}
|
|
|
|
let rule = '"{" space ';
|
|
rule += requiredProps.map(k => propKvRuleNames[k]).join(' "," space ');
|
|
|
|
if (optionalProps.length > 0) {
|
|
rule += ' (';
|
|
if (requiredProps.length > 0) {
|
|
rule += ' "," space ( ';
|
|
}
|
|
|
|
const getRecursiveRefs = (ks, firstIsOptional) => {
|
|
const [k, ...rest] = ks;
|
|
const kvRuleName = propKvRuleNames[k];
|
|
let res;
|
|
if (k === '*') {
|
|
res = this._addRule(
|
|
`${name ?? ''}${name ? '-' : ''}additional-kvs`,
|
|
`${kvRuleName} ( "," space ` + kvRuleName + ` )*`
|
|
)
|
|
} else if (firstIsOptional) {
|
|
res = `( "," space ${kvRuleName} )?`;
|
|
} else {
|
|
res = kvRuleName;
|
|
}
|
|
if (rest.length > 0) {
|
|
res += ' ' + this._addRule(
|
|
`${name ?? ''}${name ? '-' : ''}${k}-rest`,
|
|
getRecursiveRefs(rest, true)
|
|
);
|
|
}
|
|
return res;
|
|
};
|
|
|
|
rule += optionalProps.map((_, i) => getRecursiveRefs(optionalProps.slice(i), false)).join(' | ');
|
|
if (requiredProps.length > 0) {
|
|
rule += ' )';
|
|
}
|
|
rule += ' )?';
|
|
}
|
|
|
|
rule += ' "}" space';
|
|
|
|
return rule;
|
|
}
|
|
|
|
formatGrammar() {
|
|
let grammar = '';
|
|
for (const [name, rule] of Object.entries(this._rules).sort(([a], [b]) => a.localeCompare(b))) {
|
|
grammar += `${name} ::= ${rule}\n`;
|
|
}
|
|
return grammar;
|
|
}
|
|
}
|
|
|
|
// Helper function to group elements by a key function
|
|
function* groupBy(iterable, keyFn) {
|
|
let lastKey = null;
|
|
let group = [];
|
|
for (const element of iterable) {
|
|
const key = keyFn(element);
|
|
if (lastKey !== null && key !== lastKey) {
|
|
yield [lastKey, group];
|
|
group = [];
|
|
}
|
|
group.push(element);
|
|
lastKey = key;
|
|
}
|
|
if (group.length > 0) {
|
|
yield [lastKey, group];
|
|
}
|
|
}
|