Re: Question about defining a math macro

[Aditya Mahajan <adityam@umich.edu>]

On Sat, 24 Feb 2007, Taco Hoekwater wrote:

> Aditya Mahajan wrote:
>> Hi,
>>
>> Can I define a math macro, say \EXP that does the following:
>>
>> 1) \EXP{something} gives me, say E(something)
>> 2) \EXP_a^b{something} gives my E_a^b(something)
>>
>> That is, I want to write a macro that will only be used in the math
>> mode, that does something with its argument. But, I also want it to
>> handle _ and ^ if they are present.
>>
>> The only method that I can think of is to check _ or ^ with
>> \ifnextcharacter and go through all 5 cases (nothing, only _, only ^,
>> _ followed by ^, ^ followed by _) but this seems very inefficient. Is
>> there a better way?
>
> Actually, there is, by using a bit of black magic in the
> macro definition:
>
>   \def\EXP#1#{\bgroup\def\EXParg{#1}\doEXP}
>   \def\doEXP#1{\mfunction{E}\EXParg({\rm #1})\egroup}
>
> That extra hash mark has the effect of putting everything
> upto the next explicit left brace into #1.

Wow Taco. This is great.

Thanks,
Aditya