[Rd] NEWS.md support on CRAN

[Duncan Murdoch]

On 23/05/2015 8:51 PM, Baptiste Auguie wrote:
> John MacFarlane, the author of Pandoc, has been working on a project
> (http://commonmark.org/) to define a standard reference for Markdown*.
> There are already two reference implementations, one in javascript, the
> other in C:  https://github.com/jgm/cmark

It sounds as though there are at least two possibilities for parsers
that could be included in R:  Sundown and commonmark.  The "markdown"
package does some of what R would need to make use of Sundown, but not
all:  we really do need an R object representation of the parse tree,
for functions like news() to work with in the short term, and the help
system in the longer term.  To allow NEWS.md to be used, we'd also need
someone to work out the conventions for what's allowed (probably very
similar to the conventions for NEWS or NEWS.Rd), and write code to work
with those files.

Does anyone want to work on this?

Duncan Murdoch


> 
> Regards,
> 
> baptiste
> 
> * There was some initial controversy with the original author of
> markdown, but in the long term it's probably one of the more reliable
> sources to follow.
> 
> On 24 May 2015 at 12:00, Duncan Murdoch <murdoch.duncan at gmail.com
> <mailto:murdoch.duncan at gmail.com>> wrote:
> 
>     On 23/05/2015 9:25 AM, Gábor Csárdi wrote:
>     > On Sat, May 23, 2015 at 8:14 AM, Duncan Murdoch
>     > <murdoch.duncan at gmail.com <mailto:murdoch.duncan at gmail.com>
>     <mailto:murdoch.duncan at gmail.com <mailto:murdoch.duncan at gmail.com>>>
>     wrote:
>     > [...]
>     >
>     >     I think the harder problem is display.  CRAN can run pandoc, but can
>     >     users who install the package from source?  I would expect some obscure
>     >     platforms (like Windows ;-) would not have it available.
>     >
>     > [...]
>     >
>     > I don't think pandoc is the best way to go with NEWS.md (and README.md,
>     > actually). I would be surprised if many package maintainer built their
>     > NEWS/README files with pandoc. They just look at them at GitHub (or
>     > another similar service).
>     >
>     > GitHub has API for building HTML from
>     > MarkDown: https://developer.github.com/v3/markdown/
>     > It can build GitHub-flavored MarkDown, in which case you get links to
>     > GitHub issues, etc. or just plain MarkDown, like a GitHub README.
>     >
>     > If you don't want to rely on their service, then there are a multitude
>     > of lightweight MarkDown parsers available,
>     > e.g. https://github.com/markdown-it/markdown-it is a good one IMO.
> 
>     I wouldn't want R builds to depend on GitHub, so this sounds more
>     interesting.  I took a look at that website, and it looks problematic to
>     me:  the parser appears to be written in Javascript, and the install
>     instructions (using "npm" and "bower", whatever those are) depend on
>     some unstated prerequisites.  In principle there's no reason not to
>     allow R builds to depend on these things, but adding a dependency like
>     that implies so much testing that I can't imagine anyone who could do it
>     would want to.
> 
>     It's likely that a suitable parser could be written in some combination
>     of C and R -- Markdown is not a complicated language.
> 
>     > Pandoc is great for vignettes, but you don't need its full power for
>     > READMEs and especially not for NEWS files. In fact most NEWS.md files
>     > look good as text.
> 
>     But we do need something, and it needs to be essentially universally
>     available, or small enough to include in the R sources.  I think R
>     should eventually support Markdown as an acceptable language for
>     documentation (including NEWS.md, and also help files for functions),
>     but I think the effort required to do it now is too much.
> 
>     Duncan Murdoch
> 
>     >
>     > Gabor
>     >
> 
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