Re: Work on Issue 1320

[Thomas Morley]

Am 6. April 2012 23:04 schrieb Carl Sorensen <address@hidden>:
> On 4/5/12 12:51 PM, "Marc Hohl" <address@hidden> wrote:
>
>>
>>
>>Does it make sense to replace the definitions in bar-line.cc/span-bar.cc
>>with the scheme equivalents? If yes, I'd draw a patch and would include
>>one example for integrating user-defined bar lines with the new approach
>>as a snippet (once I get the dashed bar line right in place ...)
>
> It seems to me that it makes sense to put the stencil building functions
> in Guile instead of in c++.  No sense adding the extra interface layer for
> scheme calls from c++.
>
> I would suggest that you make custom-bar-print-alist and
> custom-bar-glyph-alist context properties, so they will be documented and
> available for modification.
>
> Whenever I see Scheme code that says something like
>
> (do ((
>    ...
>     (set!  foo bar)))
>
> I cringe a bit. This looks like a direct statement-by-statement
> translation from c++, rather than an implementation in native Scheme
> idioms.  set! creates a side effect for the procedure, and the Scheme
> gurus like to avoid side effects as much as possible (at least they did 25
> years ago ... am I really that old?).  I haven't looked carefully at your
> code to write an alternative, but it's likely that this code can be
> rewritten either as a recursive function or as a map, fold, or apply
> function, all of which are more native Scheme idioms.
>
> Anyway, overall this looks like great work, and I think we ought to get it
> into the code base.
>
> Thanks,
>
> Carl

I'm working on a very similiar stuff. But I didn' try to rewrite
lily/bar-line.cc etc.
I tried another approach, defining only drawing-functions for glyphs
of string-length = 1
Putting them together with a recursive function.

Please note:
This is work in progress. You may recognize many fragments of your and
Nicolas' work. Thanks to you both.
Currently there are a lot of inconsequences and small issues. And I
didn't work on the line-break and the span-bar so far.
That's on my todo-list. :)

Nevertheless, I'm able to print very curious custom-barlines.
Perhaps you may get some ideas for your own work.

-Harm

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