Re: [frogs] chord_name_engraver - help with c++ ...

[Wols Lists <antlists@xxxxxxxxxxxxxxx>]

On 05/07/11 00:55, Carl Sorensen wrote:
> On 7/4/11 5:25 PM, "Wols Lists" <antlists@xxxxxxxxxxxxxxx> wrote:
> 
>> This frog is back ... I said I'd wait until 2.14 which has finally
>> arrived :-) But I've revamped my code a bit and am having problems...
>>
>>       SCM capopitch = get_property ( "capoPitch" );
>>       bool capo = false;
>>       Pitch *c_p = unsmob_pitch (capopitch);
>>       if ( c_p != NULL )
>>       {
>>         if ( &c_p::get_notename != 0 || &c_p::get_alteration != NATURAL )
>>         {
>>           capo = true;
>>         }
>>       }
>>
>> I assume the simplest test to tell if capoPitch has been set is to
>> unsmob it? Presumably if the property hasn't been set, the pointer will
>> be returned as NULL?
> 
> I'm going out on a limb here, because I haven't tested this, but I think I'd
> check for capopitch ==  SCM_EOL to see if it hasn't been set.
> 
>>
>> Then, a pure c++ problem, when I'm testing for notename and alteration,
>> I'm getting compile errors:
>>
>> chord-name-engraver.cc: In member function Ovoid
>> Chord_name_engraver::process_music()¹:
>> chord-name-engraver.cc:108: error: Oc_p¹ is not a class or namespace
>> chord-name-engraver.cc:108: error: Oc_p¹ is not a class or namespace
>>
>> Given that Pitch is declared as a class in pitch.hh, and when I tried
>> "c_p->get_notename" it blew up with a different error, this implies my
>> c++-fu is wanting :-( Can you help me with the correct syntax?
> 
> Please don't use c_p; we want to use full words, rather than abbreviations.
> 
> I'd try
> 
> c_p->get_notename ()
> 
> And I'd recommend the code be something like
> 
>        SCM capo_pitch = get_property ("capoPitch");
>        bool capo = false;
>        if !(capo_pitch == SCM_EOL)
>          capo = (Pitch::compare (unsmob_pitch (capo_pitch), Pitch()) != 0)
> 
> Note -- I haven't tested this code.  But I think it follows the general
> trend.
> 
> HTH,
> 
Thanks - it helps A LOT.

I'd found this - as you can see from my other email - and was trying to
go down this exact path, but it was still blowing up on me. I'll use
this and it should tell me where I'm going wrong. But it's quarter past
one in the morning and my wife will not be happy if I'm not in bed soon,
so I'll carry on tomorrow :-)

Thanks again,
Cheers,
Wol

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