On Mar 31, 2016, at 16:15 , David Roe wrote: > On Thu, Mar 31, 2016 at 7:11 PM, Justin C. Walker <jus...@mac.com> wrote: > >> >> On Mar 31, 2016, at 15:37 , Vincent Delecroix wrote: >> >>> On 31/03/16 18:22, Johannes wrote: >>>> On 31.03.2016 23:08, Justin C. Walker wrote: >>>>> 2. Is there a way to tell, when hasattr(X, "foo") returns True, >>>>> whether "X.foo" can be called? >>>> >>>> X.foo and x.foo.__call__ is None >>> >>> !? >>> >>> The only way to go here is >>> >>> if callable(X.foo): >>> print "X.foo is callable" >> >> Thanks for the all the responses. They help, but I'm sensing confusion >> (at least on my part): >> >> sage: Q >> Univariate Quotient Polynomial Ring in xbar over Rational Field with >> modulus x^2 >> >> sage: hasattr(Q,"is_integral_domain") >> True >> >> sage: Q.is_integral_domain >> <built-in method is_integral_domain of >> PolynomialQuotientRing_generic_with_category object at 0x19c8dcec0> >> >> sage: callable(Q.is_integral_domain) >> True >> >> sage: Q.is_integral_domain() >> --------------------------------------------------------------------------- >> NotImplementedError Traceback (most recent call last) >> <ipython-input-48-73145f43c3d0> in <module>() >> ----> 1 Q.is_integral_domain() >> NotImplementedError: >> >> Help and corrections much appreciated, as always. >> > > Just because a method is callable doesn't mean that it can't raise > exceptions, including NotImplementedErrors. There's no reasonable way to > tell if a method will raise an exception or not without calling it.
Shazbat! I was afraid of that. Thanks for the clarification. Back to the keyboard... -- Justin C. Walker, Curmudgeon at Large Institute for the Absorption of Federal Funds ----------- My wife 'n kids 'n dogs are gone, I can't get Jesus on the phone, But Ol' Milwaukee's Best is my best friend. ----------- -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
