binomial does not accept float

[sagetrac-Henryk-Trappmann]

sage: binomial(0.5r,5)
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call
last)

/home/bo198214/projects/<ipython console> in <module>()

/opt/sage-4.5-linux-32bit-ubuntu_10.04_lts-i686-Linux/local/lib/
python2.6/site-packages/sage/rings/arith.pyc in binomial(x, m)
   2887     if isinstance(x, (float, sage.rings.real_mpfr.RealNumber,
   2888                       sage.rings.real_mpfr.RealLiteral)):
-> 2889         P = x.parent()
   2890         if m < 0:
   2891             return P(0)

AttributeError: 'float' object has no attribute 'parent' 

CC: @kcrisman

Component: basic arithmetic

Author: Johan Bosman

Reviewer: Douglas McNeil, Karl-Dieter Crisman

Merged: sage-4.7.1.alpha0

Issue created by migration from https://trac.sagemath.org/ticket/9633

[sagetrac-johanbosman]

Author: Johan Bosman

[sagetrac-dsm]

comment:4

Two points: (1) I think "P = parent(x)" is simpler, if I'm reading sage.structure.parent correctly. (2) Doctest? :^)

[sagetrac-johanbosman]

Attachment: trac_9633_binomial_float.patch.gz

[sagetrac-johanbosman]

comment:5

Good points. :).

[kcrisman]

comment:6

Certainly looks good! Interesting that we didn't catch that when we put it in, even though it explicitly has 'float' in the previous version :(

Currently running tests in case there was something subtle about x.parent() that was different from parent(x), though I can't see what that would be ...

[kcrisman]

Reviewer: Douglas S. McNeil, Karl-Dieter Crisman

[kcrisman]

comment:7

Pass :) Good catch.

[jdemeyer]

Merged: sage-4.7.1.alpha0

[jdemeyer]

Changed reviewer from Douglas S. McNeil, Karl-Dieter Crisman to Douglas McNeil, Karl-Dieter Crisman