Re: Is gcc able to handle anonymous functions?

[Joe Neeman]

On Thu, Jul 5, 2012 at 12:37 AM, address@hidden <address@hidden> wrote:

On 4 juil. 2012, at 20:10, Marc Hohl wrote:

> Am 04.07.2012 13:29, schrieb David Kastrup:
>> Marc Hohl <address@hidden> writes:
>>
>>> Hello list,
>>>
>>> the topic is somewhat over my head, but perhaps someone with more
>>> insight can answer this question?
>> I think that gcc likely can, don't know about g++, and we don't want to
>> rely on it anyhow.
> Ok.
>
> Well then, is there an alternative?
>
> I want to get rid of bar-line.cc (issue 1320), and I have managed to get all
> definitions but Bar_line::non_empty_barline into scheme.
>
> In lily/note-spacing.cc, I have
>
> Grob *bar = Pointer_group_interface::find_grob (right_col,
>                                                     ly_symbol2scm ("elements"),
> Bar_line::non_empty_barline);
>
> The simple approach
>
> bool non_empty_barline =
> ly_scm2bool (scm_call_1 (ly_lily_module_constant ("bar-line::non-empty-barline"), right_col->self_scm ()));
>
> with
>
> (define-public (bar-line::non-empty-barline grob)
> (and (grob::has-interface grob 'bar-line)
>     (pair? (ly:grob-extent grob grob X))))
>
> doesn't work.
>

I just realized that there's an easier way to do this w/ existing code conventions.  You can overload Pointer_group_interface::find_grob so that it accepts a simple closure as the third argument.  Then, wrap the Scheme function in a simple closure.

Why not just leave the function in C++? I have nothing against porting things to scheme, but in this case it just seems like an exercise in making things more complicated, for no gain.

Cheers,

Joe