96 lines
2.4 KiB
TypeScript
96 lines
2.4 KiB
TypeScript
import { AnyNode, Elem, Fragment, TextNode } from "../core/node.ts";
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import { isNil } from "../core/utils.ts";
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import { Parser } from "./types.ts";
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const RE_NEW_LINE = /^\r?\n/;
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const RE_OPEN_ATX_HEADING = /^\s{0,3}(#{1,6})(\s|$)/;
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const RE_CLOSE_ATX_HEADING = /(^|\s+)#*\s*$/;
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export class MarkdownParser implements Parser {
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parse(input: string): AnyNode {
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const ast: AstDocument = { kind: AstKind.Document, content: [] };
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let readStr = input;
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while (readStr.trim().length) {
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{
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// 1. clear new line character
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const match = RE_NEW_LINE.exec(readStr);
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if (!isNil(match)) {
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readStr = readStr.slice(match[0].length);
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}
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}
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// 2. try to find atx heading sequence
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const match = RE_OPEN_ATX_HEADING.exec(readStr);
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if (!isNil(match)) {
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readStr = readStr.slice(match[0].length);
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const atxHeading: AstAtxHeading = {
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kind: AstKind.AtxHeading,
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level: match[1].length as HeadingLevel,
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content: [],
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};
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ast.content.push(atxHeading);
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if (match[2].length > 0) {
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const endMatch = RE_CLOSE_ATX_HEADING.exec(readStr);
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const headingContent = !isNil(endMatch)
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? readStr.slice(0, endMatch.index)
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: readStr.includes("\n")
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? readStr.slice(0, readStr.indexOf("\n") + 1)
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: readStr;
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readStr = readStr.slice(
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headingContent.length + (endMatch?.[0].length ?? 0),
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);
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if (headingContent.length) {
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const text: AstText = {
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kind: AstKind.Text,
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content: headingContent.trim(),
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};
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atxHeading.content.push(text);
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}
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}
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} else {
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break;
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}
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}
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return new Fragment(ast.content.map(Heading));
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}
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}
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function Heading(ast: AstAtxHeading): Elem {
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return new Elem(`h${ast.level}`, {}, ast.content.map(Text));
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}
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function Text(ast: AstText): TextNode {
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return new TextNode(ast.content);
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}
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// AST
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type AstDocument = BaseAstItem<AstKind.Document, AstDocumentChild[]>;
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type AstDocumentChild = AstAtxHeading;
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interface AstAtxHeading extends BaseAstItem<AstKind.AtxHeading, AstText[]> {
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level: HeadingLevel;
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}
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type AstText = BaseAstItem<AstKind.Text, string>;
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type HeadingLevel = 1 | 2 | 3 | 4 | 5 | 6;
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interface BaseAstItem<K extends AstKind, Cont> {
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kind: K;
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content: Cont;
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}
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enum AstKind {
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Document,
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AtxHeading,
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Text,
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}
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