# [luatex] Changing catcodes in \directlua

Manuel Pégourié-Gonnard mpg at elzevir.fr
Tue Jul 6 10:58:33 CEST 2010

Le 06/07/2010 08:34, Paul Isambert a écrit :
> \directlua{tex.print("a\noexpand\alpha b")}
> [...] But what surprises me is the space
> before the b''. Where does it come from? I'd think \alpha'' when it
> was still a command would have gobbled it...?
>
The space is first gobbled, then another space is generated when TeX converts
the unexpanded '\alpha' token to a string of characters. If you don't want any
space, you can use \string\alpha.

This is exactly the same as \write and other TeX82 primitives. Try

\write20{|\noexpand\alpha|\string\alpha|}

and look at the terminal (or log).

Manuel.