[luatex] multiple callbacks

[Hans Hagen]

Elie Roux wrote:
> Elie Roux a écrit :
>> I took Hans' example and modified it so that it compiles. I come up 
>> with a minor Lua problem (see the last comment), and a strange 
>> problems : it seems that callbacks are called two times... If someone 
>> better than me in Lua can take a look...
> 
> Update : a simple
> 
> callback.register("hpack_filter",function(head,...)
>    texio.write_nl("I am a callback")
>    return head, true
> end,1)

no ,1 needed here; this is the luatex register function not the 
callback.add

> writes two times "I am a callback", which is not the case for

it depends on the packing of boxes, and there can be much packing going 
on (like for instance in the page builder), so even a simple

test

might give you one for 'test', one for the pagenumber, etc etc

> callback.register("post_linebreak_filter",function(h, groupcode, glyphes)
>    texio.write_nl("I am a callback")
>    return true
> end,1)
> 
> that writes it only once, is it normal?

depends on the number of paragraphs

Hans


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