Allow customizing plugin external commands

[Brendan Kidwell]

I am trying to get the Ditaa plugin to work in Windows. It looks for an executable file in $PATH called 'ditaa'.

I have in my $PATH a ~/bin folder, and I created a launcher in there for ditaa called 'ditaa.cmd'. It contains the following line of code:
   java -jar "C:\Users\kidwellb\Apps\Ditaa\ditaa0_9.jar" %*
and it should work just fine for invoking Ditaa.

The Ditaa plugin doesn't think the Ditaa CLI tool exists -- it doesn't find my launcher file. I looked into the code. See http://bazaar.launchpad.net/~jaap.karssenberg/zim/pyzim/view/head:/zim/applications.py Application#_lookup()

In Windows, _lookup() looks for the presence of '$launcher' and '$launcher.exe'. It should also look for these file extensions in addition to 'exe', which may be used to launch a command line tool: cmd, bat, vbs, py, pl, js, jar. (And others?)

Sorry I can't submit a patch because I don't quite understand the logic of this function. (What is the meaning of the 'else' clause following the 'for' statement? Is this legal?)

[Brendan Kidwell (bkidwell)]

I was viewing rev 534 of applications.py which corresponds to release 0.56.

[Jaap Karssenberg (jaap.karssenberg)]

On Tue, Apr 24, 2012 at 1:58 AM, Brendan Kidwell
<email address hidden> wrote:
> In Windows, _lookup() looks for the presence of '$launcher' and
> '$launcher.exe'. It should also look for these file extensions in
> addition to 'exe', which may be used to launch a command line tool: cmd,
> bat, vbs, py, pl, js, jar. (And others?)

Seems to me that it will be hard to get an extensive list. Maybe just
check for the name with any extension and assume it will be executable
?

> Sorry I can't submit a patch because I don't quite understand the logic
> of this function. (What is the meaning of the 'else' clause following
> the 'for' statement? Is this legal?)

Yes, the "else" is executed if the "for" finishes without a break.
See http://docs.python.org/reference/compound_stmts.html#the-for-statement
for details.

[Jaap Karssenberg (jaap.karssenberg)]

Generic mechanism for plugins to specify external application: store command in .desktop file, allow user to customize it from the preferences dialog.

[Jaap Karssenberg (jaap.karssenberg)]

Committed fix that will use the "PATHEXT" environment variable to detect what file extensions should be executable. This should solve original issue. More configuration for the complete command still open.