On Tuesday, November 15, 2016 at 4:36:01 AM UTC+1, Nils Bruin wrote:
>
> ... The "abs" in the global namespace is just the generic python one:
> abs(a) dispatches to a.__abs__()
>
> sage: class A(object):
> ....: def __abs__(self):
> ....: return "abs"
> ....:
> sage: a=A()
> sage: abs(a)
> 'abs'
> sage: sage.functions.all.abs_symbolic(a)
> TypeError: cannot coerce arguments: no canonical coercion from <class
> '__main__.A'> to Symbolic Ring
>
However, using the #21657 branch where abs is imported from functions.other
I get
sage: abs(a)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-3-6ae1d92eec8c> in <module>()
----> 1 abs(a)
/home/ralf/sage/src/sage/symbolic/function.pyx in sage.symbolic.function.
BuiltinFunction.__call__ (build/cythonized/sage/symbolic/function.cpp:11333
)()
993 res = self._evalf_try_(*args)
994 if res is None:
--> 995 res = super(BuiltinFunction, self).__call__(
996 *args, coerce=coerce, hold=hold)
997
/home/ralf/sage/src/sage/symbolic/function.pyx in sage.symbolic.function.
Function.__call__ (build/cythonized/sage/symbolic/function.cpp:6218)()
471 if callable(method):
472 return method()
--> 473 raise TypeError("cannot coerce arguments: %s" % (err
))
474
475 else: # coerce == False
TypeError: cannot coerce arguments: no canonical coercion from <class
'__main__.A'> to Symbolic Ring
so it seems the Python abs can be overridden.
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