On Sep 12, 2007, at 5:19 PM, William Stein wrote:
> On 9/12/07, Soroosh Yazdani <[EMAIL PROTECTED]> wrote:
>> BTW, I don't think this is a good idea:
>>>> sage: x, y=vars('x y')
>>>> sage: y + sin
>>>> y + sin(y)
>>>> sage: x + sin
>>>> x + sin(x)
>
> That's definitely not how SAGE works now, and now how
> it should work. This is what currently happens:
>
> sage: x,y = var('x y')
> sage: y + sin
> sin + y
> sage: x + sin
> sin + x
> sage: (x + sin)(5) # this is bad -- it's the trac ticket robert
> opened
> sin + 5 # should be sin(5) + 5.
Letting x + sin == x + sin(x) was my way of justifying (x + sin)(5)
== 5 + sin(5). I was thinking "sin" was a function of exactly one
variable, it just doesn't know/have a name for that variable yet.
Perhaps this was a bad idea, but then it is unclear what (x+sin) is.
For callable symbolic expressions I think it may be a bit clearer.
sage: f(x) = x^2
sage: f + sin
x^2 + sin(x) # because f.parent()(sin) = sin(x) ??
Also, what should (x+y+sin)(5) be? An error? 5+y+sin? What should
sin.variables() return? I think it should be a tuple with one
element, as it takes one argument... Or something special?
- Robert
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