vscode-extension-samples/test-provider-sample/src/parser.ts

import * as vscode from 'vscode';

const testRe = /^([0-9]+)\s*([+*/-])\s*([0-9]+)\s*=\s*([0-9]+)/;
const headingRe = /^(#+)\s*(.+)$/;

export const parseMarkdown = (text: string, events: {
	onTest(range: vscode.Range, a: number, operator: string, b: number, expected: number): void;
	onHeading(range: vscode.Range, name: string, depth: number): void;
}) => {
	const lines = text.split('\n');

	for (let lineNo = 0; lineNo < lines.length; lineNo++) {
		const line = lines[lineNo];
		const test = testRe.exec(line);
		if (test) {
			const [, a, operator, b, expected] = test;
			const range = new vscode.Range(new vscode.Position(lineNo, 0), new vscode.Position(lineNo, test[0].length));
			events.onTest(range, Number(a), operator, Number(b), Number(expected));
			continue;
		}

		const heading = headingRe.exec(line);
		if (heading) {
			const [, pounds, name] = heading;
			const range = new vscode.Range(new vscode.Position(lineNo, 0), new vscode.Position(lineNo, line.length));
			events.onHeading(range, name, pounds.length);
		}
	}
};