Re: want to write a perl module for Statistics of pspp

[John Darrington]

There is a PSPP "developers guide" (see the doc/dev dir) which might help you.
However don't expect it to be fully complete.

Having a perl (or Python/Scheme/Tcl/Ruby/...) interface to the high(er) level 
routines of PSPP would certainly be an interesting and usefull development.
Unfortunately I'm of the opinion that the internal routines are not yet stable
or consisten enough to be able to define such an interface (although they are
improving).  However, defineing a perl module would be a good way to identify
where we need to work on things.

Specific problems I forsee include: 
1. How should the module return its results?  Currently they are embedded in the
code generating the output tables are not well seperated.

2. In some procedures the syntax parser is inextricably entwined with the 
statistical 
calculations.

3. Because of legacy we've inherited from SPSS, procedures do not behave 
consistenly
with respect to missing values and certain defaults.  This would make the perl 
interface
more awkward or would require a lot a special casing inside the module.

Anyway, I'd be very interested to know how you get along with this project.  
Perl
and perl module specific questions are best asked on the relevant perl mailing 
lists,
but you're welcome to ask for advice about pspp internals here.

J'








On Wed, Oct 13, 2010 at 11:11:01PM +0800, ?????? wrote:
     HI, Duane
          Thanks for replying.
          and, i think i also need some documents of API of pspp C library? (if
     it exists).
          i just read source of PSPP::Wrapper, the way of it implement pspp
     function is
     1) make a tmp file by given data, and a block of pspp syntax
     2) call pspp to handle that tmp file
     3) save the result
          it's a way to call statistical procedures of pspp too. i was thinking
     that way before.
     but i think if can call the C library of pspp directly in Perl, that will 
be
     better. so i
     came here and asked for help :)
          thanks
     
     laoxie
     
     On Wed, Oct 13, 2010 at 10:45 PM, Duane Currie <address@hidden>wrote:
     
     > Hi LaoXie,
     >
     > You'd probably want to try using Perl XS.  See 'man perlxs'
     > and 'man perlxstut' for information and examples of how to
     > call C routines from Perl.
     >
     > Duane
     >
     > On Wed, Oct 13, 2010 at 10:12 AM, ?????? <address@hidden> wrote:
     > > Hi, all
     > >      i'm not sure this email is suitable or not. i'm a perl coder, and
     > for
     > > some reasons, i'm learning to use PSPP under linux.
     > >  i notice that there is a CPAN module for pspp (PSPP-Perl), but it's 
just
     > > for "read and write the system file", it can't
     > > be used to do any statistical procedures of pspp.
     > >      i think most ppl who use pspp, are mainly using the statistical
     > > procedures of pspp, so, i'm thinking if someone can
     > > write a CPAN module for statistics usage of pspp (name it
     > PSPP::Statistics
     > > ?), that will be great. for now, i want to give a try.
     > >     but i don't have much experience to write perl code with C library,
     > so i
     > > need help from here. can anyone give out
     > > some instructions/guide tour/document(URL) of API ? . so that i can 
start
     > > learning..
     > >     thanks.
     > >
     > > best regards,
     > > laoxie
     > >
     > > _______________________________________________
     > > pspp-dev mailing list
     > > address@hidden
     > > http://lists.gnu.org/mailman/listinfo/pspp-dev
     > >
     > >
     >

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