RE: Working on issue 665, how to proceed?

[lilypond]

> -----Oorspronkelijk bericht-----
> Van: David Kastrup <address@hidden>
> Verzonden: Sunday, November 17, 2019 5:20 PM
> Aan: address@hidden
> CC: 'Thomas Morley' <address@hidden>; 'Urs Liska'
> <address@hidden>; 'lilypond-devel' <address@hidden>
> Onderwerp: Re: Working on issue 665, how to proceed?
> 
> <address@hidden> writes:
> 
> >> -----Oorspronkelijk bericht-----
> >> Van: Thomas Morley <address@hidden>
> >>
> >> You use (oop goops).
> >> Is there need for it? This is a question not a hidden request!
> >> Speaking only for myself, I'm not familar with it. So reviewing your
> >> code will be difficult for me.
> >> We don't use it much so far.
> > I am a C ++ programmer and like to use classes. As you might have seen
> > I use several classes, and as far as I know goops is needed for that
> 
> Goops is a framework for classes.  It is a very, very generic framework which
> means that it doesn't really prescribe much of a programming style, and we
> don't have use of it established.
> 
> Using methods and generics (or what Guile calls differentiating function
> implementations according to type) on Guile-1.8 has significant performance
> impact.
> 
> There are some isolated modules using Goops that don't impact a lot of other
> stuff (I think a central part of the part combiner).
> 
> In general "I am a C ++ programmer and like to use classes." is an iffish 
> proposal
> for things interfacing with user programming and also gives some interplay
> with who will work with code.
> 
> MusicXML conversion _is_ isolated from what users in general do.  And it
> definitely warrants building an extensible framework for conversion.  So using
> it _if_ it helps extending the conversion capabilities easily seems like a
> reasonable idea as long as one does not "infect" other code with generics 
> (like
> overloading existing operators).  The performance for MusicXML conversion
> itself does not seem critical.
> 
> > I did use a lot of define-method, as it is easy this way to be type
> > save.
> 
> I don't think the cost justifies the effort here.  Scheme is not intended as a
> "type safe" language.
> 
> --
> David Kastrup

David,

Thank for your input.

At the moment I decided to use Goops, I realized it should have performance 
impact.
But it will (at least for me) speed up the development.
I am sure that all the work I am doing can be rewritten without using Goops 
(Goops itself is also written without using Goops 😉 )
I am aware of the problems that can arise when I overload functions in other 
modules, or worse operators.
I do think that when the musicxml conversion is working satisfactorily, we can 
rewrite a part of the code to avoid classes and methods without too much effort.

In the mean time I start working with all of your suggestions, and after that I 
go extend the conversion until the entire music part is converted. 
I will continue to push to my own git repository, until I think the conversion 
script is ready for a serious proposal.

And until that I will continue to ask the community for feedback.

At the same time I encourage you to use what I have written so far, and 
appreciate your feedback

Jaap de Wolff