A proposed scheme for parsing preformatted alt text

[easeout at tilde.team]

On Thu, Sep 10, 2020 at 12:43:10PM -0400, Gary Johnson wrote:
> Just to throw another idea out there:
> 
> There has been some extended discussion now on the mailing list about a
> conflict in machine-readable vs human-readable content being added after
> the opening pre-formatting ``` characters. It seems that enough people
> in the Gemini community see both of these kinds of information as
> providing value, but the spec currently lacks a clear path forward for
> differentiating between them.
> 
> Right now, anything written after the closing pre-formatting ``` chars
> isn't being used as per the spec's instructions. I can't help but wonder
> what would happen if we were able to put machine-readable instructions
> (like "table", "image", "code:python") on the opening line (so that
> clients could switch their line interpreter modes accordingly) and place
> human-readable alt text (mainly for screen readers) on the closing line
> (assuming the screen reader will probably just skip over the
> pre-formatted block's contents anyway and then read the alt text if
> provided).

This is a possible solution to the conflict, and I don't mind it. I do
think machine-readable on the top line and human-readable on the bottom
line is natural too, because we put captions beneath figures, and
because the top slot is already used in e.g. GitHub Markdown for
language specifiers.