Re: [PATCH 3/3] emacs: Add "Source" field to 'guix-info' buffers.

[Alex Kost]

Ludovic Courtès (2014-11-09 20:45 +0300) wrote:

> Alex Kost <address@hidden> skribis:
>
>> This patch adds URL of a package source and 2 buttons ("Show" and
>> "Download") to an ‘info’ buffer (see the attached screenshot).
>>
>> Pushing the "Show" button displays a store path of the package source.
>> Pushing the "Download" button has the same meaning as “guix build -S …”.
>
> This is very cool!
>
> I had in mind a slightly simpler user interface: just a “View source”
> button.  The thing would build (package-source-derivation p),
> effectively downloading it if it’s not already present, and opening it
> in dired.

I don't think opening in dired should be a default (although I made
‘guix-package-info-find-source-p’ variable +for you+ for this case)
because there may be a big compressed tarball that a user wouldn't like
to uncompress with emacs tar-mode.  I think displaying a link is the
preferable variant as a user can open the file or copy its path if he
wants.

Also you suggest to make “View source” synchronous: build a source
derivation, download it and open in dired.  Did I understand it right?

As this process may take a long time (for big sources or for git
checkouts if a user doesn't have a necessary git infrastructure), I
think it should be evaluated asynchronously in a REPL and it's not
possible (at least not easy) to define what value was returned by a REPL
command, so no way to define what file to open in dired.

Also what if I want to define whether there is a source in the store or
not?  (And I don't want to download it if it's not there.)  With your
variant of a single “View source” button it would not be possible, as
the source that doesn't exist in the store will be downloaded
unconditionally.

> With the interface you propose, things might be slightly confusing:
> sometimes clicking on “Download” will do nothing (because the source is
> already there), sometime “Show” will work without “Download”, sometimes
> not, etc.  Also it takes up quite a bit of space.

Sorry, I didn't get it.  What space do you mean?

> WDYT?

Pushing a “Download” button will always do something: it will run some
command in a REPL and will always display a store path in the end.  And
«Hey, USER, what did you expect from a “Download” button if the source
is already downloaded?»

But if you find it confusing what about the following variant: initially
there will be only “Show” button and when you press it, “Download”
button appears only if the source does not exist in the store.  After
a successful downloading, it disappears again.

-- 
Alex