Pretty printers for versioned namespace

[François Dumont]

On 10/01/2017 13:39, Jonathan Wakely wrote:
> I've committed the attached patch, which passes the tests for the
> default configuration and the versioned namespace configuration.
>
> I added another helper function, strip_versioned_namespace, which is
> more expressive than doing typename.replace(vers_nsp, '') everywhere.
> I've also renamed vers_nsp to _versioned_namespace (using the naming
> convention for global variables private to the module). I've added
> checks so that if that variable is None then the extra printers and
> special cases for the versioned namespace are skipped. That's not
> currently used, but it would allow us to optimise things later if
> needed.

Very nice feature indeed, see below.

>
> I also needed to update the new SharedPtrMethodsMatcher to add
> "(__\d+)?" to the regular expression.
>
>
>> @@ -1392,47 +1406,54 @@ def register_type_printers(obj):
>>     add_one_type_printer(obj, 'discard_block_engine', 'ranlux48')
>>     add_one_type_printer(obj, 'shuffle_order_engine', 'knuth_b')
>>
>> +    # Consider optional versioned namespace
>> +    opt_nsp = '(' + vers_nsp + ')?'
>> +
>>     # Do not show defaulted template arguments in class templates
>>     add_one_template_type_printer(obj, 'unique_ptr<T>',
>> -            'unique_ptr<(.*), std::default_delete<\\1 ?> >',
>> -            'unique_ptr<{1}>')
>> +        '{0}unique_ptr<(.*), std::{0}default_delete<\\2 ?> 
>> >'.format(opt_nsp),
>> +        'unique_ptr<{2}>')
>
> This is ugly. Mixing python string formatting with regular expressions
> makes it harder to read, and is inconsistent with how the versioned
> namespace is handled elsewhere. In Printer.add_version and
> add_one_type_printer we just register two names, one using std:: and
> one using std::__7::. We can do the same for the template type
> printers.

     Yes, your approach is much nicer even if it results in more type 
printer registered.

     My plan was to submit the attached patch but this doesn't work as 
the python module seems to be loaded before libstdc++.so. If you know a 
way to test for versioned namespace before starting registering printers 
this patch might still be useful. Otherwise I will just forget it.

François
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