[luatex] Getting the extra primitives?

[Taco Hoekwater]

Joseph Wright wrote:
> On 16/02/2010 15:43, luigi scarso wrote:
>> On Tue, Feb 16, 2010 at 1:14 PM, Joseph 
>> Wright<joseph.wright at uea.ac.uk>  wrote:
>>> Hello all,
>>>
>>> Thanks for the help thus far. I'm now stuck on the next step, I'm 
>>> afraid.
>>> With a file to build a format something like:
>>>
>>> \catcode `\{ = 1 \relax
>>> \catcode `\} = 2 \relax
>>> \catcode `\# = 6 \relax
>>> \catcode `\^ = 7 \relax
>>> \catcode `\^^I = 10 \relax
>>> \begingroup\expandafter\expandafter\expandafter\endgroup
>>> \expandafter\ifx\csname directlua\endcsname\relax
>>> \else
>>>   \long\def\pdfstrcmp#1#2{%
>>>     \directlua
>>>       {%
>>>         joseph.strcmp("\luaescapestring{#1}","\luaescapestring{#2}")%
>>>       }%
>>>   }
>>>   \directlua
>>>     {
>>>       tex.enableprimitives('',tex.extraprimitives ())
>>>       module("joseph",package.seeall)
>>>       function strcmp(A, B)
>>>         if A == B then
>>>           tex.write("0")
>>>         elseif A<  B then
>>>           tex.write("-1")
>>>         else
>>>           tex.write("1")
>>>         end
>>>       end
>>>     }
>>> \fi
>>> \dump
>>>
>>> If I then try building the format and using it, with something as 
>>> simple as
>>>
>>> \ifnum\pdfstrcmp{a}{b}=0\TRUE\else\FALSE\fi
>>>
>>> I get:
>>>
>>> ! LuaTeX error<\directlua>:1: attempt to index global 'joseph' (a nil
>>> value)
>>> stack traceback:
>>>         <\directlua>:1: in main chunk.
>>> \pdfstrcmp ...ring {#1}","\luaescapestring {#2}")}
>>>
>>> <*>  \ifnum\pdfstrcmp{a}{b}
>>>                           =0 \TRUE\else\FALSE\fi
>>> ?
>>>
>>> Obviously I'm still getting something wrong.
>>
>> joseph  = joseph  or { }
>>
>> Next you need to implement strcmp function
>>
>> function joseph.strcmp(A,B)
>> -- your implementation here
> 
> Further testing suggests the issue may be slightly different to my 
> original explanation. As far as I can tell, if I use \pdfstrcmp as 
> defined above during the format-creation process then all is fine (for 
> example if I just stick \pdfstrcmp{a}{a} just before \dump): no errors. 
> However, if I try to use if after making a format then I get the error 
> as described. The conclusion is that the lua part of the set up does not 
> survive the format-creation process. This seems to be very odd: am I 
> getting something wrong? After all, the whole point of a format is that 
> it is a pre-compiled and self-contained entity.

Lua stuff is not saved in the format unless you put in a lua bytecode
register (wrapped in a function). This is inconvenient, I know, but
serializing a whole lua state is a lot of work and therefore not done
(yet?).

Best wishes,
Taco