Re: LOGO-L> QUESTION ON CONDITIONAL OUTPUTS

[George Mills <mills@softronix.com>]

You could also add more error checking to the library
procedure itself, so that it can report some potential
problems.

Error checking is also something that I think I see
way to little of.

For example in the ADDLISTS example.
A VERY obvious error check would be both lists
contain the same amount of elements.
Also check that each element contains something
that can be "added".

If this function ADDLISTS became a library procedure
it would be extremely helpful for a new user of the procedure.

MSWLogo/UCBLogo have some wonderful error handling abilities.

jstclair@omsd.cerf.fred.org wrote:
> 
> Please reply to bh@anarres.CS.Berkeley.EDU (Brian Harvey)  or
> logo-l@gsn.org   NOT   logo-list@gsn.org  or  me.
> 
>                         -John-
> --Message below re-posted by <jstclair@omsd.cerf.fred.org>
> Date - 22 Apr 1998 03:30:53 GMT
> >From - bh@anarres.CS.Berkeley.EDU (Brian Harvey)
> To - jcstclair@omsd
> Subject - Re: LOGO-L> QUESTION ON CONDITIONAL OUTPUTS
> Usenet: comp.lang.logo
> ------------------
> Post Usenet mail to comp-lang-logo@ucbvax.berkeley.edu
> ------------------
> 
> Yehuka <yehuka@beitberl.ac.il> writes:
> >    ? doesn't like 3 as input  in map1
> >    [output combine (apply :map.template firsts :template.lists) (map1 bfs
> >:template.lists :template.number+1)]
> >This sort of message "frightens" the average user.
> 
> Yeah, on my list of unfinished projects is a way to allow a user-defined
> procedure to be treated as a primitive for error-message purposes, so that
> the message will refer to the caller of the library procedure instead of
> something inside it.  But it's not high on the list because it means
> poking at the part of the interpreter I hate most.  :-)

-- 
===============================================================
George Mills
email: mills@softronix.com
http://www.softronix.com
The www page contains some very powerful educational software.
Our single most important investment is our kids.
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