Re: Buffers (gone) in MK IV (was: MK IV & Lilypond)

[Hans Hagen <pragma@wxs.nl>]

Mojca Miklavec wrote:
> On 8/21/07, David Wooten wrote:
>> Greetings all,
>>
>> Has anyone had any luck getting the lilypond module to work with mkiv/
>> luatex engine? It fails for me (works fine with mkii/pdftex). I can
>> send along some log info if others have found it to work.
> 
> Hans has mentioned several times that buffers are not going to be
> written to files with luaTeX any more. This has a weird consequence on
> many modules which relied exactly on that trick.
> 
> Short example of what goes wrong:
> 
> \starttext
> 
> \startbuffer[a]
> Hello world!
> \stopbuffer
> \typebuffer[a]
> 
> %\executesystemcommand{dosomethingwith \jobname-a.tmp}
> \stoptext
> 
> The problem is that MK II created a file \jobname-a.tmp and lilypond
> module processed exactly that file further. In MK IV, that file is not
> created any more (you can check that by running the above example with
> --lua first and then with pdfTeX again. Only in the second case a file
> [whateverthefilename]-a.tmp is created.)
> 
> Lilypond module relied on that "feature" (I would rather call it
> dirty-but-very-useful-trick).
> 
> Hans, what's the current general recipe for this kind of [mis]use of buffers?

I'll add savebuffer to core-buf.*

% engine=luatex

\startluacode
     if not buffers.save then
         function buffers.save(name)
             if not name or name == "" then
                 name = tex.jobname
             end
             local b, f = buffers.data[name], 
string.format("%s-%s.tmp",tex.jobname,name)
             b = (b and type(b) == "table" and table.join(b)) or b or ""
             io.savedata(f,b)
         end
     end
\stopluacode

\def\savebuffer{\dosingleempty\dosavebuffer}

\def\dosavebuffer[#1]{\ctxlua{buffers.save("#1")}}

\starttext

\startbuffer[oeps]
oeps
\stopbuffer

\startbuffer
oepsoeps
\stopbuffer

\savebuffer[oeps] \savebuffer

\stoptext



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