I think global=False would be a nice option, also because there seem
to be more differences between a symbolic variable created using "var"
and "new_var" than just the scope; I noticed that while "var" creates
a symbolic variable, "new_var" creates an expression (class
'sage.symbolic.expression.Expression') which cannot be used in the
same way, e.g. solve_mod(3*x == 1, 10) is ok for x created using "var"
but causes an error for x created using "new_var".
On Jun 16, 9:53 pm, Utpal Sarkar <doe...@gmail.com> wrote:
> Thanks!
>
> On Jun 16, 9:30 pm, William Stein <wst...@gmail.com> wrote:
>
> > On Tue, Jun 16, 2009 at 9:12 PM, Utpal Sarkar<doe...@gmail.com> wrote:
>
> > > Hi,
>
> > > It looks like locally defined symbolic variables are always global, in
> > > particular they overwrite globally defined variables of the same name:
> > > sage: d = 0
> > > sage: def f():
> > > ....: d = var('d')
> > > ....: d = 1
> > > ....:
> > > sage: d
> > > 0
> > > sage: f()
> > > sage: d
> > > d
> > > (I put the d = 1 in the function definition to show the difference in
> > > behaviour)
>
> > Use new_var:
>
> > sage: d=0
> > sage: def foo(n):
> > ... d = sage.calculus.var.new_var('d')
> > ... print d^n
> > ...
> > ...
> > sage: foo(10)
> > d^10
> > sage: d
> > 0
>
> > Maybe var(global=False) should be an option?
>
> > William
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