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  • Committer: Bazaar Package Importer
  • Author(s): Adam Conrad
  • Date: 2005-12-05 01:26:14 UTC
  • mfrom: (1.1.2 upstream)
  • Revision ID: james.westby@ubuntu.com-20051205012614-qom4xfypgtsqc2xq
Tags: 1.2.3dfsg1-3ubuntu1
Merge with the final Debian release of 1.2.3dfsg1-3, bringing in
fixes to the clean target, better documentation of the libdb4.3
upgrade and build fixes to work with swig1.3_1.3.27.

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subversion/bindings/swig/python/README
 
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                                -*- text -*-
 
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TRANSLATING PARAMETER LISTS
 
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   The argument-reductions laws of the SWIG bindings something go like
 
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   this:
 
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     - Python functions don't return errors.  They throw exceptions.
 
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       Which means that...
 
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     - ...Python functions will return the "other" stuff that the C
 
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       functions "return" instead.  C functions which populate
 
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       pointers with new data (you know, values that are returned to
 
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       the caller, but not as "return values") will return those
 
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       values directly in Python.  So:
 
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          error = foo (object **returned_obj, int blah);
 
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       becomes:
 
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          try:
 
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              returned_obj = foo (blah)
 
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          except:
 
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              # handle it
 
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     - Callback function/baton pairs get reduced to just callback
 
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       functions, and the benefit you get from batons is gotten
 
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       instead through Python default arguments:
 
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          error = foo (callback_t function, void *baton);
 
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       becomes:
 
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          try:
 
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              def function(callback_arg1, ..., userdata1=whatever, ...):
 
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                  # do stuff here
 
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              foo(function)
 
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          except:
 
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              # handle it