On Thu, Jun 27, 2013 at 1:26 AM, Felix Salfelder <fe...@salfelder.org> wrote:
> Hi Stefan.
>
> On Thu, Jun 27, 2013 at 08:58:28AM +0200, Stefan Behnel wrote:
>> Make doesn't know that either. Cython at least knows which ones are used
>> directly. Handling transitive dependencies would require parsing header
>> files. If you need to keep track of changes in transitively included header
>> files, why not cimport from them in the Cython source to make them an
>> explicit dependency?
>
> explicit dependency tracking would imply "manual". which is painful and
> error-prone. without running gcc -M (with all flags) you cannot even
> guess the headers used transitively. I haven't found a gcc -M call
> within the cython souce code.
Why would it be needed?
>> > now what any other compiler will do.
>
>> This sentence barely passes through my English parser and then fails to
>> link with the rest.
>
> I'm sorry -- read that as noR [cythonize will know] what any other
> compiler will do.
>
>> > i have no idea how
>> > to fix that (design flaw?), and its currently easier to just use
>> > makefiles from the beginning. with makefiles, dependencies are easy and
>> > fast, if all involved compilers support it.
>>
>> Maybe you should start by describing more clearly what exactly is missing
>> in the current setup. Building with make instead of distutils seems like a
>> major complication to me all by itself.
>
> Its still just that "cython does not track (all) build dependencies".
> but lets make a short story long:
>
> look at /src/module_list.py within the sage project. it contains lots of
> references to headers at hardwired paths. these paths are wrong in most
> cases, and they require manual messing with build system internals
> *because* cythonize does not (can not?) keep track of them.
Ah, I know a bit more here. module_list.py is structured so because it
grew up organically by people with a wide range programming
backgrounds and one of the explicit goals of cythonize was (among
other things) to remove the needs for such explicit and error-prone
declarations. module_list.py has not been "simplified" yet because it
was a moving target (I think it was rebased something like a dozen
times over a period of about a year before we decided to just get
cythonize() in and do module_list cleanup later).
It should be entirely sufficient, even for sage.
> building with make (read: autotools) just works the way it always did
> (+ some obvious quirks that are not currently included within upstram
> autotools) -- after patching cython.
Can you explain? Are you saying you can type
cython -M *.pyx
make
> (i know, that many people hate autotools, and i don't want to start a rant
> about it, but it would be better for everybody if
> a) make/autotools was taken seriously
> b) the missing functionality will be implemented into cython(ize) some
> day, start with dependencies, then port/reimplement the AC_* macros )
One of the goals of Cythonize is to *only* handle the pyx -> c[pp]
step, and let other existing tools handle the rest.
- Robert
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