>>>>> "CY" == C Y <smustudent1@yahoo.com> writes:
CY> --- Daniel Lemire <daniel.lemire@acadiau.ca> wrote:
>> Ah! Yes, I didn't get the clue.
>>
>> As far as the original fellow is concerned though, chances are that
>> PLUS won't have been defined...
>>
>> There is something strong in this syntax though... isn't it???
>>
>> If it were me, I would *require* that one use 'PLUS and not PLUS...
>> I guess I don't know enough lisp to understand...?
CY> I'm confused - is there some reason PLUS shouldn't work? I'm quite
It does. Until you give PLUS a value.
CY> sure the natural impulse for most people would be to type PLUS rather
CY> than 'PLUS. I concede it doesn't work, but maybe we should fix it so
CY> that PLUS is acceptable in that instance? Or better still, allow left,
CY> right, plus and minus as arguements?
I think it has to do with evaluation. On a clean maxima, if I type X
at the prompt, I get X back because it's a variable. If I assign 42
to X, when I type X at the prompt, what do you want to happen? You
expect 42 to be printed. If you want "X" to be printed, you have to
say 'X.
This is what is happening with limit.
I suppose we add code so that plus and minus were special so that you
couldn't assign values to them, but this seems very ugly. Where do
you stop? And why should I be disallowed from giving values to my
variable named plus?
This is also similar to what you have to do with changevar. The first
arg needs to be quoted to prevent it from being evaluated before
getting passed on to changevar.
Ray