[pdftex] Using value set via \typein

[Heiko Oberdiek]

On Fri, Oct 21, 2005 at 12:37:17PM +0200, Dario Teixeira wrote:

> I am using the \typein command with pdflatex to generate
> on demand a PDF file with/without colour links.
> 
> However, this does work: (the dots stand for the full
> hyperindex options)
> 
> \typein[\colouroutput]{Enter "true" or "false".}
> \hypersetup{pdftex,...,colorlinks=\colouroutput}
> 
> Interesting enough, if I test \colouroutput with
> \ifthenelse, then it works: (though obviously an
> ugly solution)
> 
> \ifthenelse{\equal{\colouroutput}{true}}{%
> \hypersetup{pdftex,...,colorlinks=true}}{%
> \hypersetup{pdftex,...,colorlinks=false}}
> 
> What am I missing?...

Surprising, that people complain, if all works ...,
however if you want to have problems:
It is safer to use expanded values: colorlinks=true instead
of colorlinks=\coloroutput. Otherwise it is difficult to know
for the key value parser, when the value must be expanded
and when it shouldn't. There are a lot of parsers, all
acting differently: LaTeX, keyval, xkeyval, ...

Thus the second version is fine. Alternative for hackers
without package ifthen:

\begingroup
  \edef\x{\endgroup
    \noexpand\hypersetup{colorlinks=\coloroutput}%
  }%
\x

Yours sincerely
  Heiko <oberdiek at uni-freiburg.de>
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