Re: [luatex] Getting the extra primitives?

[Joseph Wright]

On 16/02/2010 11:13, Taco Hoekwater wrote:
Straight from pdftexmds:
\long\def\...@strcmp#1#2{%
   \directlua0{%
     oberdiek.pdftexcmds.strcmp("\luaescapestring{#1}",%
         "\luaescapestring{#2}")%
   }%
}%

With:

function strcmp(A, B)
   if A == B then
     tex.write("0")
   elseif A<  B then
     tex.write("-1")
   else
     tex.write("1")
   end
end

In lua, you can simply compare strings using the math operators.

Hello Taco,

Thanks for that (and to Manuel too): I was not sure if there were any 
"pitfalls". Also, that simulates \pdfstrcmp itself, but I was wondering 
about doing the entire functions (missing out all of the \ifnum and 
\expandafter stuff). In partial pseudo-code (and using LaTeX3-style 
function naming):

function strcmp:xxTF (A,B,C,D)
  if A == B then
    [Leave C on input stream]
  else
    [Leave D on input stream]
  end
end

(Also, am I correct in thinking that there is no way to avoid needing 
\unexpanded to get the string comparison "as is"?)
--
Joseph Wright