Re: [NTG-context] Determing if the argument is one character or not

4 Feb 2009


      On Wed, 4 Feb 2009, Hans Hagen wrote:
...
Aditya Mahajan wrote:
...
Hi,
I want to write a macro which behaves differently depending on whether its 
argumet is a single character or not.
\MACRO[a] should give $X_{a}$
\MACRO[a:b] should give $X_{[a:b]}$
Any hints on how to do this?
\def\MACRO[#1#2]%
 {\doifelsenothing{#2}
    {$X_{#1}$}
    {$X_{[#1#2]}$}}
Duh. I should really try to understand TeX parsing rules some day.

Thanks,
Aditya