type
block([%i:5],%i);
It gives an error: assignment: cannot assign to %i.
Try it with %pi instead of %i and you get a different error:
cannot assign to %pi; it is a declared numeric quantity.
I think this tends to set a tone ...by what Maxima already does.
using a constant as a programming variable is a no-no.
Note it is ok to ask
solve(%pi*r^2=A,%pi)
RJF
On 7/29/13 9:40 PM, Stavros Macrakis wrote:
> So what is your proposed value for diff(%i^2,%i)? ... I could
> /imagine/ a system where %i^2 would not simplify to -1 before 'diff'
> saw it, but that is a very different system from the existing Maxima.
>
> What is the value of integrate(sqrt(%i),%i,-1,0) in your system? Is
> it 2/3*%i? The "outer" %i denotes something different from the
> "inner" %i. That seems... confusing.
>
>
> On Mon, Jul 29, 2013 at 11:50 PM, Robert Dodier
> <robert.dodier at gmail.com <mailto:robert.dodier at gmail.com>> wrote:
>
> On 2013-07-27, Stavros Macrakis <macrakis at alum.mit.edu
> <mailto:macrakis at alum.mit.edu>> wrote:
>
> > I hope you're pulling my leg.
>
> Of course not.
>
> > Although Maxima is a permissive system in many ways -- and that
> is a good
> > thing -- allowing nonsensical operations without warning is
> bound to cause
> > problems. If the user really wants to use the symbol %pi for a
> variable,
> > they can subst something else for it.
>
> It isn't nonsense -- the sense of it is that the symbol is being
> used in
> a limited context with some meaning other than the one that generally
> prevails. I claim that plot2d, as do sum and integrate,
> establishes such
> a context. The difficulty, of course, is that Maxima is pretty clumsy
> about handling context in general. But it is still useful to daydream
> about what Maxima could do in a perfect world.
>
> "Everybody" knows that %pi represents the ratio of circumference to
> diameter, but what if you use a more obscure symbol?
> What if one share package declares %foo as a constant and another
> package uses it as a variable? Whose problem is it to change the
> symbol?
>
> > Besides the question of inconsistent results, there is the
> simple pragmatic
> > issue that I'm pretty confident that in the vast majority of
> cases where
> > users try to use %i, etc. as variables, that is not actually
> their intent.
>
> That is precisely the reason to allow it -- the user is, in effect,
> declaring that they don't care about the special properties of the
> symbol.
>
> best
>
> Robert Dodier
>
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