Improper parsing of strike-through

1

I think markdown parser in code mirror incorrectly parses strike through.

Given these values:

~~word~~
~~ word~~
~~word ~~
~~ word ~~

Only the first one (without any surrounding spaces) should be striked-through, according to markdown. But in codemirror, they all are.

2

Markdown has no strike-through, and the GFM spec is entirely silent on this. Which definition are you working from?

3

I used this as an extension

import {defineLanguageFacet, Language} from '@codemirror/language';
import {commonmarkLanguage, markdown} from '@codemirror/lang-markdown';
import {Strikethrough, Table} from '@lezer/markdown';

function language(parser) {
  const facet = defineLanguageFacet({block: {open: "<!--", close: "-->"}});
  const documentType = parser.nodeSet.types.find(type => type.name === "Document");
  return new Language(facet, parser, documentType);
}

const elements = [Table,  Strikethrough];

const flavouredParser = commonmarkLanguage.parser.configure(elements);

export default [
  markdown({
    base: language(flavouredParser),
    codeLanguages: [],
  }),
];

And it appears it treats ~~ word~~ as strike throught I think.

4

No I mean do you know where the behavior you’re looking for is specified?

5

I’m sorry, unfortunately I don’t know :confused:

I just noticed that’s how JetBrains IDE render ~~, and also CommonMark library in PHP, and also Github.

So I would start looking under “CommonMark specification” or “Extended markdown specification”

I would expect that ~~ should work very similarly to **, which means **text** is treated as bold, but **text **/** text** aren’t.

6

CommonMark does not define strikethrough, and GFM, the ‘spec’ that Github created for their extensions (and which I linked before) doesn’t say anything about in which situations these markers should be ignored.

This patch adds logic similar to what emphasis marks use.

7

Cool, thank you very much!

Is it released, so that I can start using it immediately?

8

I’ve tagged @lezer/markdown 1.0.2 with this fix.