Adding ids to headers

[srawlins]

I changed the (Setext)HeaderSyntax to generate an id for all headers generated, so that they can be deep-linked. This deep-linking can then also be used within a document using something like #this.

[dpeek]

While this is a very nice feature, it's not part of the markdown spec. Maybe it should be opt in or implemented in a pluggable way?

[0xcaff]

There is some minor out-of-spec stuff here already.

[dpeek]

I think it's generous to call markdown a spec anyway :P This PR doesn't currently handle duplicate heading anchors though..

[dpeek]

This actually might be better as an an option on the HtmlPrinter rather than in the parser?

[srawlins]

I think it's generous to call markdown a spec anyway :P

Agreed! 😄 Most (all?) popular markdown implementations have moved beyond the "spec" to support things like triple-backticks (as dart-markdown does) no intra-emphasis, autolinking, etc. I like the extensions hash that redcarpet uses (notice the GitHub deep link 😉 ):

markdown = Redcarpet::Markdown.new(renderer, extensions = {no_intra_emphasis: true})
markdown.render("Hello foo_bar_baz. _Bye!_")
# => "<p>Hello foo_bar_baz. <em>Bye!</em></p>"

[srawlins]

@dpeek thanks for the comments. I added uniqueness, which did largely take place in HtmlRenderer, and a test. You mentioned this might be better in the renderer than the parser... If I understand you correctly, this would involve putting HTML context in ast.dart (only apply to header tags, fetching the inner text, etc.). I like it in block_parser, since that is where the Elements are constructed anyway. What do you think?

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[srawlins]

Rebased.

[munificent]

I definitely think this is useful, but I agree with @caffinatedmonkey that it's non-standard.

I think this should be done as an extension, but that would imply having some general architecture around extensions, which isn't quite there yet. I am interested in doing that, but I probably won't have time for a while.

TL;DR: I like this, but it will be a while before I'm in a place to land it.

[munificent]

After you get the extension stuff figured out and landed, how about making this an opt-in extension?

[srawlins]

@munificent this is ready for review now. Implemented as extensions.

[munificent]

Isn't this redundant with the next line?

[srawlins]

This line kills all leading non-alphabetical characters. The next line kills all non alphanumeric+[ _-] characters, throughout. I don't think they're combinable.

[munificent]

Couple of suggestions and questions, but 👍

[srawlins]

Thanks @munificent !