Use named command variants in ConTeXt

[juh2]

The power of ConTeXt is the ability to derive named command variants like this:

\defineexternalfigure
[text]
[width=\textwidth]

\defineexternalfigure
[margin]
[width=\rightmarginwidth]

\defineexternalfigure
[full]
[width=\dimexpr\textwidth+\rightmargintotal\relax]

Three figures are defined from the default externalfigure: one for the textarea, one for the margin and one that spans the whole textarea with the margin.

The definitions are used like this inside a \placefigure environment:

\externalfigure
[image.png]
[full]
[height=3cm]

I guess that I can pass the name "full" to the output with a filter so that I can write in Markdown something like this:

:::full
![ALT](image.jpg)
:::

Any idea how to achieve that? Has anyone yet implemented such a filter?

TIA
juh

[jgm]

Currently the writer has:

  return $ braces $ "\\externalfigure" <> brackets (literal src') <> dims <> clas

where clas is the first class, in brackets, if it exists, otherwise nothing, and dims are dimension specifiers e.g. height=3in in brackets, if specified, otherwise nothing.

This suggests you could just add a class, and it looks like that works:

% pandoc -t context
![ALT](image.jpg){.full}
\startplacefigure[title={ALT}]
{\externalfigure[image.jpg][full]}
\stopplacefigure

[juh2]

Wow, it is so easy! 😄

[massifrg]

pandoc -t context
![ALT](image.jpg){.full height=3cm}
\startplacefigure[title={ALT}]
{\externalfigure[image.jpg][height=3cm][full]}
\stopplacefigure

The syntax of \externalfigure is:

\externalfigure[FILE][NAME][OPTIONS from \setupexternalfigure]

so the 2nd and 3rd argument should be swapped, like this:

\externalfigure[image.jpg][full][height=3cm]

Maybe the writer should be like this:

return $ braces $ "\\externalfigure" <> brackets (literal src') <> clas <> dims

Since the 2nd and 3rd arguments of \externalfigure are both optional, no problem arises unless you specify both class and dimensions.

[jgm]

Thanks, I've made that change.