pygccxml-development

[pygccxml-development] Incorrect code due to parameter default values

[Paul M. <pa...@sc...>]

Hello,

Py++ generates incorrect code for me that won't compile, this is with 
the svn version of yesterday.
The real problem is gccxml's stupid handling of parameter default 
values, where it
only stores the argument value literally found during parsing, which is
obviously dependent on context.

I.e. when gccxml parses

namespace doh {
enum E { ONE, TWO, THREE };
void f(int a, int b = THREE);
}

it stores for the default value of parameter b "THREE", instead of 
"doh::THREE".
Py++ then generates code that isn't put inside namespace doh, but DOES
use the value THREE. Which won't compile...

I seem to recall there was a patch for this some time ago for Py++.
Should that patch have solved all instances of this problem?
If not, would patching the gccxml output be an appropriate way of
working around this? (I.e. replacing THEE with doh::THREE).

Regards,
Paul

Re: [pygccxml-development] Incorrect code due to parameter default values

[Roman Y. <rom...@gm...>]

On Mon, Oct 27, 2008 at 12:39 PM, Paul Melis <pa...@sc...> wrote:
> Hello,
>
> Py++ generates incorrect code for me that won't compile, this is with
> the svn version of yesterday.
> The real problem is gccxml's stupid handling of parameter default
> values, where it
> only stores the argument value literally found during parsing, which is
> obviously dependent on context.
>
> I.e. when gccxml parses
>
> namespace doh {
> enum E { ONE, TWO, THREE };
> void f(int a, int b = THREE);
> }
>
> it stores for the default value of parameter b "THREE", instead of
> "doh::THREE".
> Py++ then generates code that isn't put inside namespace doh, but DOES
> use the value THREE. Which won't compile...
>
> I seem to recall there was a patch for this some time ago for Py++.
> Should that patch have solved all instances of this problem?
> If not, would patching the gccxml output be an appropriate way of
> working around this? (I.e. replacing THEE with doh::THREE).

The long version:
http://language-binding.net/pygccxml/upgrade_issues.html#free-and-member-function-default-arguments

The short version: there is nothing I can do about this and you will
have to replace default value from the script:

#f is "calldef_t" instance
for arg in f.arguments:
    arg.default_value = <<<new default value or None>>>


Another approach is described here:
http://language-binding.net/pyplusplus/documentation/functions/default_args.html

HTH

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/