Let me tone down my statement. There should be a way to have a function
return nothing, sort of like programming languages that allow subroutines as
well as functions. I don't like having to always return a value, it forces
me to return something random that could cause problems later. It is not a
panacea but it is a possible improvement in the programming language.
Rich
----- Original Message -----
From: "Barton Willis" <willisb at unk.edu>
To: "Richard Hennessy" <rich.hennessy at verizon.net>
Cc: "Maxima List" <maxima at math.utexas.edu>
Sent: Monday, October 05, 2009 6:20 AM
Subject: Re: [Maxima] Void in Maxima
Many of the functions in abs_integrate, for example, return false when the
function is unable to determine an antiderivative. Oh sure, silly things
such as integrate(1,x,0,false) break this scheme. Fixing this in some
sturdy way isn't worthwhile, I think. If you want a function to indicate
failure by returning %void instead of false or a nounform, that's fine.
You could even tell Maxima that assignments to %void aren't allowed.
Barton
-----maxima-bounces at math.utexas.edu wrote: -----
>To: "Stavros Macrakis" <macrakis at alum.mit.edu>
>From: "Richard Hennessy" <rich.hennessy at verizon.net>
>Sent by: maxima-bounces at math.utexas.edu
>Date: 10/04/2009 09:06PM
>cc: Maxima List <maxima at math.utexas.edu>
>Subject: Re: [Maxima] Void in Maxima
>
>
>
>
>
>
>
>What about the possibility of creating a new system
>variable called void or %void that would have the properties that I
>described. I think this is desirable because many times I think a
>function
>should not return a value when the function fails at its job. This
>might be a way to resolve how to handle all of the problems with 'und,
>'ind,
>'inf and 'minf.
>
>Rich
>
>
> ----- Original Message -----
> From:
> Stavros
> Macrakis
> To: Richard Hennessy
> Cc: Maxima List
> Sent: Sunday, October 04, 2009 11:00
> AM
> Subject: Re: [Maxima] Void in
>Maxima
>
>
> On Sun, Oct 4, 2009 at 9:09 AM, Richard Hennessy
><rich.hennessy at verizon.net>
> wrote:
>
> Is there a way to cause a function to have no return
> value.
>
>No.
>
>It is possible to create a symbol
> of length 0 using ?intern("$") which has a zero-length printed form, but
>this
> has none of the properties you
> want.
>
> -s
>
>
>
>
>
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