[with patch, positive review] is_Blah functions: deprecate and then remove them from top level imports

[jhpalmieri]

Functions like is_FractionField should not be imported at the top level, since they don't necessarily make sense mathematically, only programmatically. Thus, situations like

sage: is_FractionField(FractionField(ZZ))
False

might confuse people.

See the discussion in #4149. I think the best solution, as propounded there by cremona and robertwb, is to have is_Blah methods which are, as much as possible, mathematically correct. In contrast, is_Blah functions should be data-checks, existing primarily for use in the code.

mhansen has volunteered to do at least some of this work.

[mhansen]

There still might be some failures due to ones that I missed, but I think I got most of them.

[mabshoff]

Mike,

you missed a couple (this is with -long):

sage -t -long devel/sage/sage/calculus/calculus.py
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/calculus.py", line 5587:
    sage: is_CallableSymbolicExpression(f)
Expected:
    True
Got:
    doctest:1: DeprecationWarning: 
    Using is_CallableSymbolicExpression from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    True
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/calculus.py", line 431:
    sage: is_SymbolicExpression(SR(I))
Expected:
    True
Got:
    doctest:1: DeprecationWarning: 
    Using is_SymbolicExpression from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    True
**********************************************************************
2 items had failures:
   1 of   8 in __main__.example_159
   1 of   9 in __main__.example_7
***Test Failed*** 2 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_calculus.py

parent_old.pyx:

sage -t -long devel/sage/sage/structure/parent_old.pyx      
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/parent_old.py", line 45:
    sage: is_Parent(Primes())
Expected:
    True
Got:
    False
**********************************************************************
1 items had failures:
   1 of   6 in __main__.example_1
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_parent_old.py
         [3.1 s]
exit code: 1024

schemes.py:

sage -t -long devel/sage/sage/schemes/generic/scheme.py     
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/scheme.py", line 41:
    sage: from sage.scheme.generic.scheme import is_Scheme
Exception raised:
    Traceback (most recent call last):
      File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/local/lib/python2.5/doctest.py", line 1228, in __run
        compileflags, 1) in test.globs
      File "<doctest __main__.example_1[2]>", line 1, in <module>
        from sage.scheme.generic.scheme import is_Scheme###line 41:
    sage: from sage.scheme.generic.scheme import is_Scheme
    ImportError: No module named scheme.generic.scheme
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/scheme.py", line 42:
    sage: is_Scheme(5)
Expected:
    False
Got:
    doctest:1: DeprecationWarning: 
    Using is_Scheme from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    False
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/scheme.py", line 505:
    sage: from sage.schemes.generic.schemes import is_AffineScheme
Exception raised:
    Traceback (most recent call last):
      File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/local/lib/python2.5/doctest.py", line 1228, in __run
        compileflags, 1) in test.globs
      File "<doctest __main__.example_23[2]>", line 1, in <module>
        from sage.schemes.generic.schemes import is_AffineScheme###line 505:
    sage: from sage.schemes.generic.schemes import is_AffineScheme
    ImportError: No module named schemes
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/scheme.py", line 506:
    sage: is_AffineScheme(5)
Expected:
    False
Got:
    doctest:1: DeprecationWarning: 
    Using is_AffineScheme from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    False
**********************************************************************
2 items had failures:
   2 of   6 in __main__.example_1
   2 of   6 in __main__.example_23
***Test Failed*** 4 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_scheme.py
         [11.2 s]
exit code: 1024

free_monoid.py:

sage -t -long devel/sage/sage/monoids/free_monoid.py        
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/free_monoid.py", line 75:
    sage: is_FreeMonoid(5)
Expected:
    False
Got:
    doctest:1: DeprecationWarning: 
    Using is_FreeMonoid from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    False
**********************************************************************
1 items had failures:
   1 of   6 in __main__.example_2
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_free_monoid.py
         [2.3 s]
exit code: 1024

free_ablian_monoid.py:

sage -t -long devel/sage/sage/monoids/free_abelian_monoid.py
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/free_abelian_monoid.py", line 98:
    sage: is_FreeAbelianMonoid(5)
Expected:
    False
Got:
    doctest:1: DeprecationWarning: 
    Using is_FreeAbelianMonoid from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    False
**********************************************************************
1 items had failures:
   1 of   6 in __main__.example_2
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_free_abelian_monoid.py
         [2.5 s]
exit code: 1024

A strange on in magma.py:

sage -t -long devel/sage/sage/interfaces/magma.py           
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/magma.py", line 1096:
    sage: R.assign_names(['x'])
Exception raised:
    Traceback (most recent call last):
      File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/local/lib/python2.5/doctest.py", line 1228, in __run
        compileflags, 1) in test.globs
      File "<doctest __main__.example_28[2]>", line 1, in <module>
        R.assign_names(['x'])###line 1096:
    sage: R.assign_names(['x'])
    AttributeError: type object 'R' has no attribute 'assign_names'
**********************************************************************
1 items had failures:
   1 of   3 in __main__.example_28
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_magma.py
         [3.3 s]

homset.py:

sage -t -long devel/sage/sage/categories/homset.py          
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/homset.py", line 190:
    sage: is_Endset(S)
Expected:
    True
Got:
    doctest:1: DeprecationWarning: 
    Using is_Endset from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    True
**********************************************************************
1 items had failures:
   1 of  10 in __main__.example_3
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_homset.py
         [2.3 s]
exit code: 1024

and finally functor.pyx:

sage -t -long devel/sage/sage/categories/functor.pyx        
**********************************************************************
File "/scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/functor.py", line 38:
    sage: is_Functor(F)
Expected:
    True
Got:
    doctest:1: DeprecationWarning: 
    Using is_Functor from the top level is deprecated since it was designed to be used by developers rather than end users.
    It most likely does not do what you would expect it to do.  If you really need to use it, import it from the module that it is defined in.
    True
**********************************************************************
1 items had failures:
   1 of  12 in __main__.example_1
***Test Failed*** 1 failures.
For whitespace errors, see the file /scratch/mabshoff/release-cycle/sage-3.1.3.alpha2/tmp/.doctest_functor.py
         [2.3 s]
exit code: 1024

Other than that the patch looks good.

Cheers,

Michael

[mhansen]

I've updated the patch to fix those issues.

[mabshoff]

Ok, things work now. Positive review. Followup work should be directed to new tickets.

Cheers,

Michael

[mabshoff]

Merged in Sage 3.1.3.alpha2