Re: [Chicken-users] is case-lambda expensive?

[Kon Lovett]

On May 24, 2006, at 9:25 AM, Matthew David Parker wrote:

> Hi I've got functions for my SDL layer that I want to put like this:
>
> (define msdl.pixel
>         (case-lambda
>                 (() (printf "(msdl.pixel x y rgb alpha [img])\n"))
>                 ((x y rgb alpha)
>                         (R_msdl.pixel (int x) (int y) (int rgb) (int alpha) 0))
>                 ((x y rgb alpha img)
>                         (R_msdl.pixel (int x) (int y) (int rgb) (int alpha) 
> img))))
>
> This way the user can type in:
> > (msdl.pixel)
> (msdl.pixel x y rgb alpha [img])
>
> so that it's easy to see how to use the command.  However, if there is
> some program where the user wants to draw 1000 pixels quickly, will  
> the
> case-lambda make it significantly slower?

Try ,x (case-lambda ...) w/ csi to see what code is actually  
generated. Assuming you compile w/ (inline) this isn't too bad.

Are you sure you want to saddle all your public procedures w/ the  
lambda docu? If you compile w/ the default debugging level it will  
add lambda info for you.

Ex: (w/ csi)

#;1> (define (msdl.pixel x y rgb alpha #!optional (img 0)) 'foo)
#;2> (procedure-information msdl.pixel)
(msdl.pixel x y rgb alpha #!optional (img 0))
#;3> (msdl.pixel 3)
Error: too few arguments - received 1 but expected 4: #<procedure  
(msdl.pixel x y rgb alpha #!optional (img 0))>

        Call history:

        <eval>          (msdl.pixel 3)  <--

And (w/ csc)

Error: too few arguments - received 1 but expected 4: #<procedure  
(msdl.pixel x3 y4 rgb5 alpha6 . g27)>

        Call history:

        t1.scm: 3    msdl.pixel                 <--

> Thanks,
> Matt
>
> (btw, "msdl" is just a temporary name, as there is already an  
> "msdl" for
> SDL)
>
>
> _______________________________________________
> Chicken-users mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/chicken-users