[Maxima] Representing the case "no result"
drdieterkaiser at web.de
Mon Jun 8 15:59:10 CDT 2009
Am Montag, den 08.06.2009, 06:10 -0700 schrieb Richard Fateman:
> Robert Dodier wrote:
> > ...
> > Why invent this special convention at all? Why go to the
> > trouble of it, when we can just as easily have a symbol
> > or expression which explicitly indicates an error?
> If the error looks like a return value, say "error43" then maxima will
> do arithmetic with it, including
> error43-error43 --> 0.
Yes, this was one of my main problems. What expression we can return
which Maxima does not use for further calculations.
> >> By the way: I am thinking about a way to support the user with
> >> additional information about the calculation. One way could be to write
> >> messages in a global list, which can be inspected by the user.
> This would not be a bad idea, in my opinion, as an additional
> technique: e.g.
> save all error messages optionally in a global list during a
> computation. Then at the end, the list could
> be inspected, even if all the messages were squelched during the
> computation. Then the list
> could be reset. E.g. set error messages "off" but save them on a list
> would be an option.
> Mathematica sort of has this when it says something like
> error xxx
> error xxx
> ... there were 43 more errors error xxx during this computation.
As written in another posting my first idea was to implement a standard
function to print a user message. Such a standard function like
user_message() could be extended very easy to support new
More information about the Maxima