[Feat] Support frontmatter

[huyz]

Obsidian-style frontmatter seems to throw off the highlighting in the first Markdown section(s)

[sbarex]

Please explain the problem better.

[soreavis]

@huyz @sbarex — I looked into this. Good news: QLMarkdown already renders YAML frontmatter — it's just scoped to .rmd/.qmd files by default, so on a plain .md (Obsidian, Jekyll, Hugo…) it isn't recognized and the frontmatter ends up being parsed as ordinary Markdown. That's what "throws off the first section(s)".

What's actually happening

With the default setting, a normal .md file's frontmatter is handed straight to the Markdown parser, which reads it literally: the opening --- becomes a horizontal rule, the key: value lines become a paragraph, any - item lines become a bullet list, and the closing --- becomes a second horizontal rule. So this note:

---
title: My Note
tags:
  - foo
  - bar
aliases: [a, b]
---

# Actual Heading

renders, at defaults, as:

<hr />
<p>title: My Note
tags:</p>
<ul><li>foo</li><li>bar
aliases: [a, b]</li></ul>
<hr />
<h1>Actual Heading</h1>

That <hr> + paragraph + stray list at the very top is the mangled first section you're seeing, @huyz.

The fix (already in the app)

Open Preferences and find the "YAML header" pull-down in the extensions list (its title shows the current mode, e.g. "YAML header (.rmd, .qmd files)"). Switch it from "Only for Rmd and Qmd files" to "For all md files". The CLI equivalent is --yaml all.

With that on, the same file renders the frontmatter as a clean metadata table instead:

<table><tr><td align='right'><strong>title</strong></td><td>My Note</td></tr> … </table>
<h1>Actual Heading</h1>

Why it's not the default @sbarex (for anyone else reading)

Turning frontmatter detection on for all .md isn't free: a document that legitimately starts with ---, has some content, then hits another ---/... line will have that region pulled out and rendered as YAML rather than as horizontal rules / a setext heading. Scoping the default to .rmd/.qmd avoids surprising plain-Markdown users, and "For all md files" is the opt-in for people who live in frontmatter. So the current behavior is deliberate — this is really "the setting exists, but it's off for the file type most people hit it with."

Small suggestion

Two things make this easy to miss: the control is labeled "YAML header" rather than "frontmatter" (the term Obsidian/Jekyll users search for), and the common case — plain .md — is exactly the one it's off for. A tooltip/label mention of "frontmatter", or a note in the README, would probably head off repeat reports. Totally your call given the false-positive trade-off above — just flagging it since .md frontmatter is so common now.

[huyz]

@soreavis Thansk for that! very well hidden. It took me a while to find it even with your instructions lol