Robert Bradshaw wrote:
> On Dec 3, 2008, at 10:28 AM, adrian wrote:
>
>> In the following code:
>> sage: x=CC['x'].gen()
>> sage: type(x)
>> <class
>> 'sage.rings.polynomial.polynomial_element_generic.Polynomial_generic_d
>> ense_field'>
>> sage: f(x)=sin(x)
>> sage: type(x)
>> <class 'sage.calculus.calculus.SymbolicVariable'>
>>
>> Is this intended?
>
> Yes. Otherwise one would need to write var('x') before writing f(x) =
> sin(x).
Wow, Sage will redefine symbols that are already existing to accommodate
what should be a dummy variable? This looks seriously wrong and looks
like it could really mess things up.
For example:
sage: f(sage) = sin(sage)
sage: type(sage)
<class 'sage.calculus.calculus.SymbolicVariable'>
sage: f(i) = i^2
sage: type(i)
<class 'sage.calculus.calculus.SymbolicVariable'>
sage: i^2
i^2
I would strongly prefer that this is wrapped so that a local symbolic
variable is used that is not tied to anything, or even just so that the
value of x is reset after the function is assigned. Are we using
sage.calculus.calculus.var in the code so that we don't inject into the
global namespace, just like the docstring of var says?
Jason
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