Re: extracting a zip archive via elisp (with no external executables)

[Eli Zaretskii]

> From: Saulius Menkevičius <address@hidden>
> Date: Sun, 9 Jul 2017 22:26:45 +0300
> Cc: Alan Third <address@hidden>, Emacs developers <address@hidden>
> 
> I am one of the maintainers of the C# package for emacs 
> https://github.com/OmniSharp/omnisharp-emacs
> For the package to work properly it needs to run language server, which
> should be downloaded from 
> https://github.com/OmniSharp/omnisharp-roslyn/releases
> 
> I have added a new interactive command omnisharp-install-server which
> downloads and installs the server to 
> ~/.emacs.d/.cache/omnisharp/server/<version> directory.
> Thus aleviating the need for the user to navigate to web page, download, 
> extract
> and the configure package to point to the location where the server has been 
> extracted.
> 
> For UNIX systems things are easy, I just download tarball and extract it with 
> (call-process „tar“ .. „xz“..)
> 
> But on Windows things get tough, apparently.

Not really.  This should get them going:

     (w32-shell-execute "open" "FILENAME.zip")
or
     (w32-shell-execute "explore" "FILENAME.zip")

(replace FILENAME.zip with the actual file name).  This will open the
Windows Explorer showing the contents of the zip archive, and you
should tell your users to click "File->Extract all" to extract the
files into the directory of their choosing.

> Instructing the user to install 7-zip or something else manually kind of
> invalidates the purpose of automatic installation.

Please never suggest to install 7z, it's not Free Software on Windows
(and on Unix it's less capable to make it Free Software).  If someone
needs 7z capabilities, the best Free Software alternative is bsdtar
from the libarchive project.