Determing if the argument is one character or not

Determing if the argument is one character or not

[Aditya Mahajan]

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?

Thanks,
Aditya
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Re: Determing if the argument is one character or not

[Hans Hagen]

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}
      {$X_{#1}$}
      {$X_{[#1#2]}$}}


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If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________

Re: Determing if the argument is one character or not

[Wolfgang Schuster]

Am 04.02.2009 um 00:11 schrieb Aditya Mahajan:

> 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?

To test for the number argument use \counttoken(s) and to check
if the string contains a ":" use \doifinstring/\doifinstringelse.

Wolfgang

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Re: Determing if the argument is one character or not

[Aditya Mahajan]

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
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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archive  : https://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Determing if the argument is one character or not

[Aditya Mahajan]

On Wed, 4 Feb 2009, Wolfgang Schuster wrote:

>
> Am 04.02.2009 um 00:11 schrieb Aditya Mahajan:
>
>> 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?
>
> To test for the number argument use \counttoken(s) and to check
> if the string contains a ":" use \doifinstring/\doifinstringelse.

Thanks. For the moment, I will go with Hans's solution, since it is much 
simpler.

Aditya
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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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archive  : https://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________