Re: [frogs] Re: Capo-ChordNames

[Wols Lists <antlists@xxxxxxxxxxxxxxx>]

On 10/08/10 14:39, Carl Sorensen wrote:

If it gets me into Scheme and C++
> I'll be well pleased.

At the moment, probably not too much Scheme (although you might want to try
writing the CapoEngraver in Scheme).

Actually, I was thinking that writing this engraver first might be a good idea, seeing as it should set capoFret as a side effect. oops :-) If Mike gets back to me with some scheme engravers to investigate, I'll try that route if I can (or I'll just try and find a few candidates myself).

> 
> I'll look at your long email, probably respond, and then hack at it and
> come back with more questions :-)

Sounds great.

But there's some wrong advice in my email, because I wasn't thinking about
having *both* chord names created by the engraver.  You'll want to follow up
more on your original approach, i.e. having both pitches and capo_pitches.
Then you'll need to call the chordNameFunction twice, once with pitches,
bass, inversion and once with capo_pitches, capo_bass, capo_inversion.  Then
you'll need to combine the two markups into one, probably with another
scheme call.

Actually, I was wondering if I could take a different approach ...

I've twigged that scm_call_4 simply calls the procedure in argument 1 with four more arguments. It MIGHT be possible to rewrite that instead. I've got a nasty feeling, however, that there are a whole bunch of chord name functions, so that's probably a non-starter :-(

Do you know if I'll need capo_inversion, or can I just use inversion? Don't worry about investigating if you don't know, it's more experience for me :-) but it's quicker to ask than duplicate knowledge :-)

vertical/horizontal should be a context property, rather than a keyword.

I'm not sure yet about capo_fret.  It could be a context property, or it
could be part of the structure of a capoEvent.

For getting started, I'd recommend making it a context property, and
avoiding the use of a capoEvent.

Then you'd do something like

\set ChordNames.capoFret = #3
\set ChordNames.capoOffset = #'horizontal

to set up the engraver properly.

Okay. Next task. Actually sit down and start writing some code, then post it to the list to see if it makes sense :-)

Cheers,
Wol