Lua filters: file path as argument to pandoc.read()? (Especially to read YAML files into a (meta)data structure)

Lua filters: file path as argument to pandoc.read()? (Especially to read YAML files into a (meta)data structure)

[BPJ]

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Is it possible in some way to pass a file path as argument to pandoc.read()
in Lua filters or do you have to first get a string using Lua's io.open()
and file:read()? If no would it maybe be a good idea to allow passing a
table `{ file = 'path/to/file'}` instead of a string to read from a file?
This is assuming that the problems I am having opening files with Lua from
inside filters (I think the files are not found) may not be present from
Haskell.

Also is there some way to read a YAML file into a (meta)data structure
without manually making sure that the string starts/ends with
`---\n`/`\n...\n`? Using `yaml = yaml:gsub('^%s*%-%-%-%%s*', ''):gsub('^',
'---\n')` and its EOS counterpart is a rather blunt method.

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Re: Lua filters: file path as argument to pandoc.read()? (Especially to read YAML files into a (meta)data structure)

[Albert Krewinkel]

BPJ <melroch-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> writes:

> Is it possible in some way to pass a file path as argument to
> pandoc.read() in Lua filters or do you have to first get a string using
> Lua's io.open() and file:read()? If no would it maybe be a good idea to
> allow passing a table `{ file = 'path/to/file'}` instead of a string to
> read from a file?

I had been contemplated something similar in the past: My idea was to
provide functions to generate 'Sources', which is the structure passed
to custom readers. A `Source` argument would be easy to distinguish from
a string, and `read` could be made to parse the source.

My conclusion was that it might be nice, but that it's not worth the
effort for the time being.

> This is assuming that the problems I am having
> opening files with Lua from inside filters (I think the files are not
> found) may not be present from Haskell.

Huh, quite weird. Might be an encoding issue. Possibly related:
https://github.com/jgm/pandoc/issues/6077

> Also is there some way to read a YAML file into a (meta)data structure
> without manually making sure that the string starts/ends with
> `---\n`/`\n...\n`?

That's the hack I'm using as well. The best would probably be to install
a Lua library that binds to libyaml and to use that.


-- 
Albert Krewinkel
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