search

marp-team / marp-cli

A CLI interface for Marp and Marpit based converters
MIT License
1.85k stars 105 forks source link

Add support for `lang` directive #542

Closed ludelafo closed 10 months ago

ludelafo commented 1 year ago

In order to use the hyphens CSS property as mentioned in https://github.com/marp-team/marp-vscode/issues/430, a new lang global directive must be implemented.

A starting point would be https://github.com/marp-team/marp-cli/blob/d0cee502f2785e1a2f998f3afc831849e3f6efc9/src/marp-cli.ts and https://github.com/marp-team/marp-cli/blob/d0cee502f2785e1a2f998f3afc831849e3f6efc9/src/engine/meta-plugin.ts by adding a lang directive.

I see at https://github.com/marp-team/marp-cli/blob/d0cee502f2785e1a2f998f3afc831849e3f6efc9/src/templates/layout.pug#L2 that the HTML lang is set here. If I understand it correctly, this value is passed by the --lang argument of the CLI where a new global directive should also set this value if set.

Please correct me if I'm wrong. I would be glad to implement this feature if you are interested.

yhatt commented 1 year ago

Currently Marp CLI uses the locale of running OS as the value for the lang attribute of the <html> element. https://github.com/marp-team/marp-cli/blob/d0cee502f2785e1a2f998f3afc831849e3f6efc9/src/config.ts#L293

Unlike similar options for metadata, the CLI argument --lang is not supported in the current Marp CLI, and changes are only supported in the lang field of the configuration file. Therefore, it may be a little hard to contribute for that.

This decision was made to prevent unnecessary confusion for not specialized users. Providing an easily changeable CLI option / global directive might lead unintended rendering output and a bit of confusion, especially in East Asian languages. https://heistak.github.io/your-code-displays-japanese-wrong/

However, considering the appropriate purpose of "document-level language setting", adding --lang option and the lang global directive support would be justified.

yhatt commented 11 months ago

This issue may be best drilling down to Marp Core, and even Marpit, the framework to build a core.

The lang attribute can be used on any tag, not just <html>. Given that the snippets of slides generated by Marp are also used by third-party implementations outside of the official Marp tools, so it is better to have the lang attribute on each slide tags, rather than the <html> tag. (Note that it's not meaning to remove lang attribute from <html> provided by Marp CLI templates)

If there were lang attribute in each slide, the display reproducibility of the slide in cases where multiple languages are mixed in a single HTML. e.g. a web page/app with Marp slides as a part of HTML.

ludelafo commented 10 months ago

Thank you very much @yhatt!