Re: ConTeXt Marcro Quesiton

[Aditya Mahajan <adityam@umich.edu>]

On Mon, 5 Feb 2007, Aditya Mahajan wrote:

> Hi,
>
> I wand to write a macro, that handles both [] and {} as optional
> arguments. For example, I have a command with three optionl arguments
>
> [#1][#2]#3
>
> I want
>
> \command                to give #1=\empty, #2 = \empty, #3 = \empty
>
> \command [1]            to give #1=1, #2 empty, #3 empty,
>
> \command [1] {3}        to give #1=1, #2 empty, #3 = 3
>
> \command [1] [2] {3}    to give #1=1, #2=2, #3=3
>
> \command {3}            to give #1=empty, #2=empty, #3=3.
>
> I tried the following macro, it works except for \command[1][2]{3}.
>
> \def\finalcommand[#1][#2]#3%
>   {1 :-> (#1), 2 :-> (#2), 3 :-> (#3)}
>
> \def\command%
>   {\dodoubleempty\docommand}
>
> \def\docommand[#1][#2]%
>   {\dodoublegroupempty{\finalcommand[#1][#2]}}
>
> \starttext
>
> \command
>
> \command [1]
>
> \command [1] {3}
>
> \command [1] [2] {3}
>
> \command {3}
>
> \stoptext
>
> which gives
>
> 1 :-> (), 2 :-> (), 3 :-> ()
> 1 :-> (1), 2 :-> (), 3 :-> ()
> 1 :-> (1), 2 :-> (), 3 :-> (3)
> 1 :-> (1), 2 :-> (2), 3 :-> () 3 <--------- This does not work
> 1 :-> (), 2 :-> (), 3 :-> (3)
>
> Can someone suggest a better way to do this?

I found another way, I hope that it has no gotcha's

\def\finalcommand[#1][#2]#3%
   {1 :-> (#1), 2 :-> (#2), 3 :-> (#3)}

\def\command%
   {\dodoubleempty\docommand}

\def\docommand[#1][#2]%
   {\def\useoneargument##1{\finalcommand[#1][#2]{##1}}
    \def\fakeoneargument{\finalcommand[#1][#2]{}}
    \doifnextcharelse\bgroup{\useoneargument}{\fakeoneargument}}

Aditya