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>wrote:
> On 2013-07-27, Stavros Macrakis <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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