Re: SCM-ification of parser

[Han-Wen Nienhuys]

Erik Sandberg schreef:
> Hi,
>
> The attahed patch changes all Music* types in the parser to SCM. I think I 
> fixed some memory leaks also.

yes, this is good.

> The next step in parser split-up is to move rules out to Scheme. There will be 
> a lot of functions, so I suggest we create a new make-music.scm for this.

Regarding naming, we already have a make-foo-music for plain SCM use. I 
propose to have

 foo:  bar baz
    ;


=>

  (make-syntax-foo .. )

It would also be nice if you could fold in various other runtime 
configuration mechanisms (eg. lookup for -| -^ and other scripts, the 
pipeSymbol hack).

Also, I'm not sure if -in the long run- you should use 
lily_module_constant. I think it makes more sense to store the 
production rules in the parser object, just like the definition of eg. 
pipeSymbol.

> We will need a mechanism for handling music origins in a good way. I suggest 
> that an optional parameter for origin is added to all make-*-music functions 
> (or perhaps even automate this with a define-make-music-function macro)

There is already generic location support from the bison side, using $@ 
I think. I think it's best to use that.

> In order to verify that I don't break stuff, I plan to do the following:
> For each rule that will be moved out, I first create some .ly code that the 
> rule is used for. Then I move the rule out to Scheme, and verify that 
> \displayMusic still gives the same output.
>
> The reson why I start with this before music streams are implemented, is that 
> many rules need to be exported, so when patch reviewing lag comes in the way 
> for continuing music stream work, I can use my time to export a couple of 
> rules instead.

As long as you move carefully, and don't break lilypond , that should be 
fine.

--

Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen

LilyPond Software Design
 -- Code for Music Notation
http://www.lilypond-design.com