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Diffstat (limited to 'packages/astro-parser/src/parse/index.ts')
-rw-r--r-- | packages/astro-parser/src/parse/index.ts | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/packages/astro-parser/src/parse/index.ts b/packages/astro-parser/src/parse/index.ts new file mode 100644 index 000000000..124e125ef --- /dev/null +++ b/packages/astro-parser/src/parse/index.ts @@ -0,0 +1,270 @@ +// @ts-nocheck + +import { isIdentifierStart, isIdentifierChar } from 'acorn'; +import fragment from './state/fragment.js'; +import { whitespace } from '../utils/patterns.js'; +import { reserved } from '../utils/names.js'; +import full_char_code_at from '../utils/full_char_code_at.js'; +import { TemplateNode, Ast, ParserOptions, Fragment, Style, Script } from '../interfaces.js'; +import error from '../utils/error.js'; + +type ParserState = (parser: Parser) => ParserState | void; + +interface LastAutoClosedTag { + tag: string; + reason: string; + depth: number; +} + +export class Parser { + readonly template: string; + readonly filename?: string; + readonly customElement: boolean; + + index = 0; + stack: TemplateNode[] = []; + + html: Fragment; + css: Style[] = []; + js: Script[] = []; + meta_tags = {}; + last_auto_closed_tag?: LastAutoClosedTag; + + constructor(template: string, options: ParserOptions) { + if (typeof template !== 'string') { + throw new TypeError('Template must be a string'); + } + + this.template = template.replace(/\s+$/, ''); + this.filename = options.filename; + this.customElement = options.customElement; + + this.html = { + start: null, + end: null, + type: 'Fragment', + children: [], + }; + + this.stack.push(this.html); + + let state: ParserState = fragment; + + while (this.index < this.template.length) { + state = state(this) || fragment; + } + + if (this.stack.length > 1) { + const current = this.current(); + + const type = current.type === 'Element' ? `<${current.name}>` : 'Block'; + const slug = current.type === 'Element' ? 'element' : 'block'; + + this.error( + { + code: `unclosed-${slug}`, + message: `${type} was left open`, + }, + current.start + ); + } + + if (state !== fragment) { + this.error({ + code: 'unexpected-eof', + message: 'Unexpected end of input', + }); + } + + if (this.html.children.length) { + let start = this.html.children[0].start; + while (whitespace.test(template[start])) start += 1; + + let end = this.html.children[this.html.children.length - 1].end; + while (whitespace.test(template[end - 1])) end -= 1; + + this.html.start = start; + this.html.end = end; + } else { + this.html.start = this.html.end = null; + } + } + + current() { + return this.stack[this.stack.length - 1]; + } + + acorn_error(err: any) { + this.error( + { + code: 'parse-error', + message: err.message.replace(/ \(\d+:\d+\)$/, ''), + }, + err.pos + ); + } + + error({ code, message }: { code: string; message: string }, index = this.index) { + error(message, { + name: 'ParseError', + code, + source: this.template, + start: index, + filename: this.filename, + }); + } + + eat(str: string, required?: boolean, message?: string) { + if (this.match(str)) { + this.index += str.length; + return true; + } + + if (required) { + this.error({ + code: `unexpected-${this.index === this.template.length ? 'eof' : 'token'}`, + message: message || `Expected ${str}`, + }); + } + + return false; + } + + match(str: string) { + return this.template.slice(this.index, this.index + str.length) === str; + } + + match_regex(pattern: RegExp) { + const match = pattern.exec(this.template.slice(this.index)); + if (!match || match.index !== 0) return null; + + return match[0]; + } + + allow_whitespace() { + while (this.index < this.template.length && whitespace.test(this.template[this.index])) { + this.index++; + } + } + + read(pattern: RegExp) { + const result = this.match_regex(pattern); + if (result) this.index += result.length; + return result; + } + + read_identifier(allow_reserved = false) { + const start = this.index; + + let i = this.index; + + const code = full_char_code_at(this.template, i); + if (!isIdentifierStart(code, true)) return null; + + i += code <= 0xffff ? 1 : 2; + + while (i < this.template.length) { + const code = full_char_code_at(this.template, i); + + if (!isIdentifierChar(code, true)) break; + i += code <= 0xffff ? 1 : 2; + } + + const identifier = this.template.slice(this.index, (this.index = i)); + + if (!allow_reserved && reserved.has(identifier)) { + this.error( + { + code: 'unexpected-reserved-word', + message: `'${identifier}' is a reserved word in JavaScript and cannot be used here`, + }, + start + ); + } + + return identifier; + } + + read_until(pattern: RegExp) { + if (this.index >= this.template.length) { + this.error({ + code: 'unexpected-eof', + message: 'Unexpected end of input', + }); + } + + const start = this.index; + const match = pattern.exec(this.template.slice(start)); + + if (match) { + this.index = start + match.index; + return this.template.slice(start, this.index); + } + + this.index = this.template.length; + return this.template.slice(start); + } + + require_whitespace() { + if (!whitespace.test(this.template[this.index])) { + this.error({ + code: 'missing-whitespace', + message: 'Expected whitespace', + }); + } + + this.allow_whitespace(); + } +} + +/** + * Parse + * Step 1/3 in Astro SSR. + * This is the first pass over .astro files and the step at which we convert a string to an AST for us to crawl. + */ +export default function parse(template: string, options: ParserOptions = {}): Ast { + const parser = new Parser(template, options); + + // TODO we may want to allow multiple <style> tags — + // one scoped, one global. for now, only allow one + if (parser.css.length > 1) { + parser.error( + { + code: 'duplicate-style', + message: 'You can only have one <style> tag per Astro file', + }, + parser.css[1].start + ); + } + + // const instance_scripts = parser.js.filter((script) => script.context === 'default'); + // const module_scripts = parser.js.filter((script) => script.context === 'module'); + const astro_scripts = parser.js.filter((script) => script.context === 'setup'); + + if (astro_scripts.length > 1) { + parser.error( + { + code: 'invalid-script', + message: 'A component can only have one frontmatter (---) script', + }, + astro_scripts[1].start + ); + } + + // if (module_scripts.length > 1) { + // parser.error( + // { + // code: 'invalid-script', + // message: 'A component can only have one <script context="module"> element', + // }, + // module_scripts[1].start + // ); + // } + + return { + html: parser.html, + css: parser.css[0], + // instance: instance_scripts[0], + module: astro_scripts[0], + }; +} |