[metapost] How to ignore a comma?

[L. Nobre G.]

Hint: forget about an arbitrary number of "text" arguments (I know
that forgetting is not so easy).

def somefunc( expr eone, etwo )( text tone )( text ttwo ) =
      [...]
enddef;

beginfig(1);
    pair vectors[];
    path a;
    pen b;
    [...]
    vectors0 = (23,34);
    somefunc( a, b )( dashed evenly )( vectors );
endfig;

On 04/02/07, Mojca Miklavec <mojca.miklavec.lists at gmail.com> wrote:
> Hello,
>
> This might be easy to do, but I don't know how. I would like to write
> a few simple macros accepting an arbitrary number of arguments.
> Arguments are usually passed to metapost with a comma inbetween, but
> if one sends "text" arguments, comma of course doesn't work. I could
> put semicolon or a space between, but it looks a bit unnatural.
>
> How can I ask metapost for ignoring the next character if it happens
> to be a comma? See the example below:
>
> beginfig(1);
>
> def do_something(expr xx, yy)(text t) =
>
>         % default values
>         save c; color c; c = black;
>         save d; numeric d; d = 5pt;
>
>         def set_color(expr col) =
>                 c := col;
>         enddef;
>
>         def set_size(expr size) =
>                 d := size;
>         enddef;
>
>         t;
>
>         fill fullcircle scaled d shifted (xx,yy) withcolor c;
> enddef;
>
> % simple examples
> do_something(1cm,2cm,set_color(blue));
> do_something(2cm,1cm,set_size(10pt));
>
> % this works OK
> do_something(2.5cm,1.5cm,set_color(red) set_size(8pt));
>
> % this works OK
> do_something(2cm,2.5cm,set_color(green);set_size(8pt));
>
> % but the following syntax would look better
> % do_something(2.5cm,1.5cm,set_color(red),set_size(8pt));
>
> draw unitsquare scaled 3cm;
>
> endfig;
> end.
>
>
> I would be very grateful for any hints about how to make the last
> example work. (I believe that it should be possible to do so.)
>
> Thanks a lot,
>     Mojca
> _______________________________________________
> metapost mailing list
> http://tug.org/mailman/listinfo/metapost
>


-- 
L. Nobre G. - http://lnobreg.googlepages.com/
--
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assume, and deny." Richard Heinberg in Powerdown