Re: [NTG-context] callback.register

[Wolfgang Werners-Lucchini]

  I tried the following
 
  --
  \starttext
  \startluacode
  local OldPreLB
 
  function MyPreLB(head,gc)
  ?texio.write_nl(### Here I am!)
  ?OldPreLB(head,gc)
  end
 
  OldPreLB = callback.find('pre_linebreak_filter')
  callback.register('pre_linebreak_filter',MyPreLB)
  \stopluacode
 
  Test
  \stoptext
  --
 
  but MyPreLB() is not called.
  What I am doing wrong here?
 
 Hi Wolfgang,
 
 see http://www.ntg.nl/pipermail/ntg-context/2010/047018.html
 
 -- 
 Best regards,
 
 Li Yanrui (???)

I see!

From the info found there
-
there are two user hooks:

tasks.appendaction(processors,before,modules.mine.whatever_a)
tasks.appendaction(processors,after,modules.mine.whatever_b)
-
it is not clear for me how to use this.

So it seems that the luatex reference is useless for a context user.
Is there an other documentation on this?

I have found an other mechanism in 'luat-cbk.lua' which offers a pair 
of functions 'callbacks.push()' and 'callbacks.pop()'. But I have not 
made any attempts to use them. Are they useable or are they disabled 
too?

Wolfgang
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Re: [NTG-context] callback.register

[Wolfgang Werners-Lucchini]

 Hello,
 
 Here a patch for luat-cbk.lua:
 
 function callbacks.register(name,func,freeze)
 if frozen[name] then
 if trace_callbacks then
 frozenmessage(registering,name)
 end
 return nil, name ..  is frozen
 elseif freeze then
 frozen[name] = (type(freeze) == string and freeze) or
 registered
 return register_callback(name,func)
 else
 return register_callback(name,func)
 end
 end
 
 function callback.register(name,func) -- original
 if frozen[name] then
 if trace_callbacks then
 frozenmessage(registering,name)
 end
 return nil, name ..  is frozen
 else
 return register_callback(name,func)
 end
 end
 
 (Untested...)
 
 Cheers, Peter

and

function callbacks.report()
local list = callback.list()
for name, func in table.sortedpairs(list) do
local str = frozen[name]
if str then
logs.report(callbacks,%s: %s - 
%s,state(name),name,str)
else
logs.report(callbacks,%s: %s,state(name),name)
end
end
end

Wolfgang
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Re: [NTG-context] callback.register

[Wolfgang Werners-Lucchini]

 there are two user hooks:
 
 tasks.appendaction(processors,before,modules.mine.whatever_a)
 tasks.appendaction(processors,after,modules.mine.whatever_b)
 -

My example looks now

\starttext
\startluacode
function MyPreLB(head,gc)
  texio.write(\n)
  for n in node.traverse(head) do
if node.type(n.id) == glyph then
  texio.write(string.char(n.char))
elseif node.type(n.id) == glue then
  texio.write(' ')
end
  end
  texio.write(\n)
  return head
end
tasks.appendaction(processors,before,MyPreLB)
\stopluacode
Dies ist ein Test.
\stoptext

Is it correct to return 'head'?

Wolfgang
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Re: [NTG-context] callback.register

[李延瑞]

2010/4/10 Wolfgang Werners-Lucchini w...@musensturm.de:
 there are two user hooks:

 tasks.appendaction(processors,before,modules.mine.whatever_a)
 tasks.appendaction(processors,after,modules.mine.whatever_b)
 -

 My example looks now

 \starttext
 \startluacode
 function MyPreLB(head,gc)
  texio.write(\n)
  for n in node.traverse(head) do
    if node.type(n.id) == glyph then
      texio.write(string.char(n.char))
    elseif node.type(n.id) == glue then
      texio.write(' ')
    end
  end
  texio.write(\n)
  return head
 end
 tasks.appendaction(processors,before,MyPreLB)
 \stopluacode
 Dies ist ein Test.
 \stoptext

 Is it correct to return 'head'?


Maybe 'return head, true', because I found a few functions in the beta
do so. Such as 'scripts.preprocess'.

-- 
Best regards,

Li Yanrui (李延瑞)
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Re: [NTG-context] callback.register

[Peter Münster]

On Thu, Apr 08 2010, Wolfgang Werners-Lucchini wrote:

 [...]
 
 but MyPreLB() is not called.
 What I am doing wrong here?

Hello Wolfgang,

I don't know, but I've played a bit with your example file:

\starttext
\startluacode
local OldPreLB
function MyPreLB(head,gc)
  tex.print(Here I am!)
  return OldPreLB(head,gc)
end
local id, error = callback.register('pre_linebreak_filter', MyPreLB)
if id == nil then
   tex.print(Error string:, type(error), \\par)
end
\stopluacode
Problem: callback.register returns nil, but no error message.
\stoptext

Cheers, Peter

-- 
Contact information: http://pmrb.free.fr/contact/


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Re: [NTG-context] callback.register

[李延瑞]

2010/4/9 Wolfgang Werners-Lucchini w...@musensturm.de:
 Hallo,

 I tried the following

 --
 \starttext
 \startluacode
 local OldPreLB

 function MyPreLB(head,gc)
  texio.write_nl(### Here I am!)
  OldPreLB(head,gc)
 end

 OldPreLB = callback.find('pre_linebreak_filter')
 callback.register('pre_linebreak_filter',MyPreLB)
 \stopluacode

 Test
 \stoptext
 --

 but MyPreLB() is not called.
 What I am doing wrong here?

Hi Wolfgang,

see http://www.ntg.nl/pipermail/ntg-context/2010/047018.html

-- 
Best regards,

Li Yanrui (李延瑞)
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