William Stein wrote:
> On Wed, Sep 17, 2008 at 8:02 AM, Jason Merrill <[EMAIL PROTECTED]> wrote:
>> On Sep 17, 2:20 am, Jason Merrill <[EMAIL PROTECTED]> wrote:
>>> Here's a monkeypatch that makes this work(ish)
>>>
>>> from sage.calculus.calculus import SymbolicExpression
>>> class FormalSymbolicExpression(SymbolicExpression):
>>> def __init__(self,expr):
>>> self.expr = expr
>>> # just delegate everything to the input expression
>>> for m in dir(expr):
>>> self.m = m
>>> def _repr_(self,simplify=False):
>>> return self.expr._repr_(simplify=False)
>>> # implement a _latex_ method
>>>
>>> SymbolicExpression.formal = lambda self:
>>> FormalSymbolicExpression(self)
>>>
>>> def formal(expr):
>>> try:
>>> return expr.formal()
>>> except AttributeError:
>>> return expr
>> Right... so that delegation bit doesn't actually do anything. This
>> was leading to
>>
>> sage: simplify(formal(exp(I*pi)))
>> e^(pi*I)
>>
>> and presumably horrendous amounts of other strangeness. Here's
>> another try. It doesn't actually inherit from SymbolicExpression
>> anymore, which will probably cause some difficulty with isinstance
>> calls, but it's maybe a little closer
>>
>> from sage.calculus.calculus import SymbolicExpression
>> class FormalSymbolicExpression():
>> def __init__(self,expr):
>> self.expr = expr
>>
>> def __getattr__(self,attrib):
>> return getattr(self.expr,attrib)
>>
>> def __repr__(self,simplify=False):
>> return self.expr._repr_(simplify=False)
>>
>> SymbolicExpression.formal = \
>> lambda self: FormalSymbolicExpression(self)
>>
>> def formal(expr):
>> try:
>> return expr.formal()
>> except AttributeError:
>> return expr
>>
>> And now
>>
>> sage: simplify(formal(exp(I*pi)))
>> -1
>
> Jason,
>
> Just a heads up -- your code above is going to become pointless when we switch
> to using Ginac as a backend for symbolic manipulation, since Sage will no
> longer
> keep its own expression tree.
I looked at your ginac/pynac symbolic stuff last night. It appears that
you just call a Gex_to_str function (or something like that) to print
out the expression, which presumably is a ginac thing. Calling latex()
on any expression just returns \text{printed representation}. If Sage
will not maintain the expression tree, will it be able to access it to
print out a latex form? Does Ginac output latex versions of expressions?
Thanks,
Jason
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