Re: Uses langdefs.py to create language list forcreate-weblinks-itexi.py (issue 4951047)

[Phil Holmes]

----- Original Message ----- 
From: "Graham Percival" <address@hidden>
To: "Phil Holmes" <address@hidden>
Cc: <address@hidden>; <address@hidden>; 
<address@hidden>
Sent: Tuesday, September 13, 2011 7:03 PM
Subject: Re: Uses langdefs.py to create language list 
forcreate-weblinks-itexi.py (issue 4951047)


> On Tue, Sep 13, 2011 at 04:42:16PM +0100, Phil Holmes wrote:
> > The problem is - how to return WEB_LANGS for the web-build, but
> > LANGUAGES for the doc build?  My patch does this by using something
> > like this in website.make:
> >
> > WEB_LANGS =  python langdefs.py web
>
> Um.  I was just expecting you to define
> WEB_LANGS =
> on line 78 of langdefs.py ?
>
> I might have missed something (since nobody actually understands
> all parts of the build system), but surely that would be
> sufficient?  I must admit that I'm really confused about what
> we're trying to do here, or how far along that path we've gotten
> (if at all!).

That won't work, AFAICS.  Langdefs.py is used in /Documentation/GNUmakefile 
like this:

LANGS = $(shell $(PYTHON) $(top-src-dir)/python/langdefs.py)

In other words, LANGS (i.e. documentation languages) is set to equal 
whatever langdefs.py returns when it's called from the command line.  In 
python, a command-line invocation is tested for with:

if __name__ == '__main__':

In langdefs.py, we have that line followed by:

   print ' '.join ([l.code for l in LANGUAGES if l.enabled and l.code != 
'en'])

In other words, any command-line invocation of langdefs.py will always get 
every value of LANGUAGES.code except en.  Changing WEB_LANGS will have no 
effect on this.

Note that this does not apply to python code that includes langdefs.py, 
since in this case we can simply use:

langdef.WEB_LANGS

In website.make we currently have:

WEB_LANGS = cs de es fr hu it ja nl zh

which we want to change to something like

WEB_LANGS = $(shell $(PYTHON) $(top-src-dir)/python/langdefs.py)

The problem is "telling" langdefs that we want it to return to the command 
line the value of WEB_LANGS, not LANGUAGES.  I suggested doing this by 
appending an argument to the command line invocation, so if we were to do 
this, typing:

python langdefs.py

would give all the doc languages, but typing:

python langdefc.py web

would only return the web languages.  As I said, I wasn't happy with this 
approach, but it does work.  My alternative I've now experimented with is to 
set an environment variable in website.make: something like:

export MAKEWEB=1

and then pick this up in langdefs.  My plan is to put a further patch on 
Rietveld with this implementation.  I'm just explaining it here 'cos it's 
not 100% obvious why I'm doing it this way.

--
Phil Holmes