[Dev-luatex] lua in ocp's [was Very simple sample?]

Hans Hagen pragma at wxs.nl
Tue Dec 12 19:27:03 CET 2006

Javier Bezos wrote:
> Taco:
>
>
>>> which just wraps every letter inside \dolua{ }. However,
>>> the letters are silently ignored (but "print" prints it in
>>> the console, so lua is working). I presume the problem
>>> is "tex.print" is like a line in the tex file, while ocp's
>>> are applied after expansion, so when \dolua is executed
>>> it's too late and the line is sent to nowhere.
>>>
>> That is roughly what happens, yes. I have to look into this
>> at some point, because silently disappearing output is a bit
>> unfriendly, but the precise interaction between otp processing
>> and input states is not the easiest bit of TeX to comprehend,
>> so it may take a while.
>>
>
> OK. What I was wondering was if the whole OCP mechanim
> could be replaced by lua scripts. Since lua can be
> embedded in TeX, the transformations would be under the
> control of TeX and not as external files, unmodifiable
> at run time. So, I intented to write a OTP passing
> directly the OCP buffer to lua. Of course, that has
> some disadvantages since the result may need further
> expansion to reprocess it. Or perhaps not? This is what
> I liked to investigate.
>
>
lua callbacks will be avialable for each stage: input, after expansion, at various stages of list building, par building, page building, shipout etc

Hans

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