Inspect Python, Sage, and Cython objects#

This module extends parts of Python’s inspect module to Cython objects.

EXAMPLES:

sage: from sage.misc.sageinspect import *

>>> from sage.all import *
>>> from sage.misc.sageinspect import *

Test introspection of modules defined in Python and Cython files:

Cython modules:

sage: sage_getfile(sage.rings.rational)
'.../rational.pyx'
sage: sage_getdoc(sage.rings.rational).lstrip()
'Rational Numbers...'
sage: sage_getsource(sage.rings.rational)
'# distutils: ...Rational Numbers...'

>>> from sage.all import *
>>> sage_getfile(sage.rings.rational)
'.../rational.pyx'
>>> sage_getdoc(sage.rings.rational).lstrip()
'Rational Numbers...'
>>> sage_getsource(sage.rings.rational)
'# distutils: ...Rational Numbers...'

Python modules:

sage: sage_getfile(sage.misc.sageinspect)
'.../sageinspect.py'
sage: print(sage_getdoc(sage.misc.sageinspect).lstrip()[:40])
Inspect Python, Sage, and Cython objects
sage: sage_getsource(sage.misc.sageinspect).lstrip()[51:-1]
'Inspect Python, Sage, and Cython objects...'

>>> from sage.all import *
>>> sage_getfile(sage.misc.sageinspect)
'.../sageinspect.py'
>>> print(sage_getdoc(sage.misc.sageinspect).lstrip()[:Integer(40)])
Inspect Python, Sage, and Cython objects
>>> sage_getsource(sage.misc.sageinspect).lstrip()[Integer(51):-Integer(1)]
'Inspect Python, Sage, and Cython objects...'

Test introspection of classes defined in Python and Cython files:

Cython classes:

sage: sage_getfile(sage.rings.rational.Rational)
'.../rational.pyx'
sage: sage_getdoc(sage.rings.rational.Rational).lstrip()
'A rational number...'
sage: sage_getsource(sage.rings.rational.Rational)
'cdef class Rational...'

>>> from sage.all import *
>>> sage_getfile(sage.rings.rational.Rational)
'.../rational.pyx'
>>> sage_getdoc(sage.rings.rational.Rational).lstrip()
'A rational number...'
>>> sage_getsource(sage.rings.rational.Rational)
'cdef class Rational...'

Python classes:

sage: sage_getfile(BlockFinder)
'.../sage/misc/sageinspect.py'
sage: sage_getdoc(BlockFinder).lstrip()[:50]                                        # needs sphinx
'Provide a "tokeneater()" method to detect the end '
sage: sage_getsource(BlockFinder)
'class BlockFinder:...'

>>> from sage.all import *
>>> sage_getfile(BlockFinder)
'.../sage/misc/sageinspect.py'
>>> sage_getdoc(BlockFinder).lstrip()[:Integer(50)]                                        # needs sphinx
'Provide a "tokeneater()" method to detect the end '
>>> sage_getsource(BlockFinder)
'class BlockFinder:...'

Test introspection of functions defined in Python and Cython files:

Cython functions:

sage: sage_getdef(sage.rings.rational.make_rational, obj_name='mr')
'mr(s)'
sage: sage_getfile(sage.rings.rational.make_rational)
'.../rational.pyx'
sage: sage_getdoc(sage.rings.rational.make_rational).lstrip()
'Make a rational number ...'
sage: sage_getsource(sage.rings.rational.make_rational)
'@cython.binding(True)\ndef make_rational(s):...'

>>> from sage.all import *
>>> sage_getdef(sage.rings.rational.make_rational, obj_name='mr')
'mr(s)'
>>> sage_getfile(sage.rings.rational.make_rational)
'.../rational.pyx'
>>> sage_getdoc(sage.rings.rational.make_rational).lstrip()
'Make a rational number ...'
>>> sage_getsource(sage.rings.rational.make_rational)
'@cython.binding(True)\ndef make_rational(s):...'

Python functions:

sage: sage_getdef(sage.misc.sageinspect.sage_getfile, obj_name='sage_getfile')
'sage_getfile(obj)'
sage: sage_getfile(sage.misc.sageinspect.sage_getfile)
'.../sageinspect.py'
sage: sage_getdoc(sage.misc.sageinspect.sage_getfile).lstrip()
'Get the full file name associated to "obj" as a string...'
sage: sage_getsource(sage.misc.sageinspect.sage_getfile)[4:]
'sage_getfile(obj):...'

>>> from sage.all import *
>>> sage_getdef(sage.misc.sageinspect.sage_getfile, obj_name='sage_getfile')
'sage_getfile(obj)'
>>> sage_getfile(sage.misc.sageinspect.sage_getfile)
'.../sageinspect.py'
>>> sage_getdoc(sage.misc.sageinspect.sage_getfile).lstrip()
'Get the full file name associated to "obj" as a string...'
>>> sage_getsource(sage.misc.sageinspect.sage_getfile)[Integer(4):]
'sage_getfile(obj):...'

Unfortunately, no argspec is extractable from builtins. Hence, we use a generic argspec:

sage: sage_getdef(''.find, 'find')
'find(*args, **kwds)'
sage: sage_getdef(str.find, 'find')
'find(*args, **kwds)'

>>> from sage.all import *
>>> sage_getdef(''.find, 'find')
'find(*args, **kwds)'
>>> sage_getdef(str.find, 'find')
'find(*args, **kwds)'

By Issue #9976 and Issue #14017, introspection also works for interactively defined Cython code, and with rather tricky argument lines:

sage: # needs sage.misc.cython
sage: cython('def foo(unsigned int x=1, a=\')"\', b={not (2+1==3):\'bar\'}, *args, **kwds): return')
sage: print(sage_getsource(foo))
def foo(unsigned int x=1, a=')"', b={not (2+1==3):'bar'}, *args, **kwds): return
sage: sage_getargspec(foo)
FullArgSpec(args=['x', 'a', 'b'], varargs='args', varkw='kwds', defaults=(1, ')"', {False: 'bar'}), kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> # needs sage.misc.cython
>>> cython('def foo(unsigned int x=1, a=\')"\', b={not (2+1==3):\'bar\'}, *args, **kwds): return')
>>> print(sage_getsource(foo))
def foo(unsigned int x=1, a=')"', b={not (2+1==3):'bar'}, *args, **kwds): return
>>> sage_getargspec(foo)
FullArgSpec(args=['x', 'a', 'b'], varargs='args', varkw='kwds', defaults=(1, ')"', {False: 'bar'}), kwonlyargs=[], kwonlydefaults=None, annotations={})

AUTHORS:

  • Originally taken from Fernando Perez’s IPython

  • William Stein: extensive modifications

  • William Stein: in _sage_getargspec_cython(), a modified version of inspect.getargspec from the Python Standard Library, which was taken from IPython for use in Sage

  • Nick Alexander: extensions, testing

  • Simon King: some extension for Cython, generalisation of SageArgSpecVisitor

  • Simon King: in sage_getsourcelines(), if a class has no docstring then let the class definition be found starting from the __init__ method.

  • Simon King: in sage_getsourcelines(), get source lines for dynamic classes

  • Simon King: in _sage_getargspec_cython(), return an ArgSpec, fix some bugs

  • Simon King (2011-09): added _sage_getsourcelines_name_with_dot()

  • Simon King (2013-02): in _sage_getargspec_cython(), recognise varargs and default values in cython code, and return an ArgSpec

class sage.misc.sageinspect.BlockFinder[source]#

Bases: object

Provide a tokeneater() method to detect the end of a code block.

This is the Python library’s inspect.BlockFinder modified to recognize Cython definitions.

tokeneater(type, token, srow_scol, erow_ecol, line)[source]#
class sage.misc.sageinspect.SageArgSpecVisitor[source]#

Bases: NodeVisitor

A simple visitor class that walks an abstract-syntax tree (AST) for a Python function’s argspec. It returns the contents of nodes representing the basic Python types: None, booleans, numbers, strings, lists, tuples, and dictionaries. We use this class in _sage_getargspec_from_ast() to extract an argspec from a function’s or method’s source code.

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: visitor.visit(ast.parse('[1,2,3]').body[0].value)
[1, 2, 3]
sage: v = visitor.visit(ast.parse("{'a':('e',2,[None,({False:True},'pi')]), 37.0:'temp'}").body[0].value)
sage: sorted(v.items(), key=lambda x: str(x[0]))
[(37.0, 'temp'), ('a', ('e', 2, [None, ({False: True}, 'pi')]))]
sage: v = ast.parse("jc = ['veni', 'vidi', 'vici']").body[0]; v
<...ast.Assign object at ...>
sage: attrs = [x for x in dir(v) if not x.startswith('__')]
sage: '_attributes' in attrs and '_fields' in attrs and 'col_offset' in attrs
True
sage: visitor.visit(v.targets[0])
'jc'
sage: visitor.visit(v.value)
['veni', 'vidi', 'vici']

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> visitor.visit(ast.parse('[1,2,3]').body[Integer(0)].value)
[1, 2, 3]
>>> v = visitor.visit(ast.parse("{'a':('e',2,[None,({False:True},'pi')]), 37.0:'temp'}").body[Integer(0)].value)
>>> sorted(v.items(), key=lambda x: str(x[Integer(0)]))
[(37.0, 'temp'), ('a', ('e', 2, [None, ({False: True}, 'pi')]))]
>>> v = ast.parse("jc = ['veni', 'vidi', 'vici']").body[Integer(0)]; v
<...ast.Assign object at ...>
>>> attrs = [x for x in dir(v) if not x.startswith('__')]
>>> '_attributes' in attrs and '_fields' in attrs and 'col_offset' in attrs
True
>>> visitor.visit(v.targets[Integer(0)])
'jc'
>>> visitor.visit(v.value)
['veni', 'vidi', 'vici']
visit_BinOp(node)[source]#

Visit a Python AST ast.BinOp node.

INPUT:

  • node – the node instance to visit

OUTPUT: the result that node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit(ast.parse(x).body[0].value)
sage: [vis(d) for d in ['(3+(2*4))', '7|8', '5^3', '7/3', '7//3', '3<<4']] #indirect doctest
[11, 15, 6, 2.3333333333333335, 2, 48]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit(ast.parse(x).body[Integer(0)].value)
>>> [vis(d) for d in ['(3+(2*4))', '7|8', '5^3', '7/3', '7//3', '3<<4']] #indirect doctest
[11, 15, 6, 2.3333333333333335, 2, 48]
visit_BoolOp(node)[source]#

Visit a Python AST ast.BoolOp node.

INPUT:

  • node – the node instance to visit

OUTPUT: the result that node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit(ast.parse(x).body[0].value)
sage: [vis(d) for d in ['True and 1', 'False or 3 or None', '3 and 4']] #indirect doctest
[1, 3, 4]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit(ast.parse(x).body[Integer(0)].value)
>>> [vis(d) for d in ['True and 1', 'False or 3 or None', '3 and 4']] #indirect doctest
[1, 3, 4]
visit_Compare(node)[source]#

Visit a Python AST ast.Compare node.

INPUT:

  • node – the node instance to visit

OUTPUT: the result that node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Compare(ast.parse(x).body[0].value)
sage: [vis(d) for d in ['1<2==2!=3', '1==1>2', '1<2>1', '1<3<2<4']]
[True, False, True, False]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Compare(ast.parse(x).body[Integer(0)].value)
>>> [vis(d) for d in ['1<2==2!=3', '1==1>2', '1<2>1', '1<3<2<4']]
[True, False, True, False]
visit_Dict(node)[source]#

Visit a Python AST ast.Dict node.

INPUT:

  • node – the node instance to visit

OUTPUT: the dictionary the node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Dict(ast.parse(x).body[0].value)
sage: v = [vis(d) for d in ['{}', "{1:one, 'two':2, other:bother}"]]
sage: [sorted(d.items(), key=lambda x: str(x[0])) for d in v]
[[], [(1, 'one'), ('other', 'bother'), ('two', 2)]]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Dict(ast.parse(x).body[Integer(0)].value)
>>> v = [vis(d) for d in ['{}', "{1:one, 'two':2, other:bother}"]]
>>> [sorted(d.items(), key=lambda x: str(x[Integer(0)])) for d in v]
[[], [(1, 'one'), ('other', 'bother'), ('two', 2)]]
visit_List(node)[source]#

Visit a Python AST ast.List node.

INPUT:

  • node – the node instance to visit

OUTPUT: the list the node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_List(ast.parse(x).body[0].value)
sage: [vis(l) for l in ['[]', "['s', 't', 'u']", '[[e], [], [pi]]']]
[[], ['s', 't', 'u'], [['e'], [], ['pi']]]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_List(ast.parse(x).body[Integer(0)].value)
>>> [vis(l) for l in ['[]', "['s', 't', 'u']", '[[e], [], [pi]]']]
[[], ['s', 't', 'u'], [['e'], [], ['pi']]]
visit_Name(node)[source]#

Visit a Python AST ast.Name node.

INPUT:

  • node – the node instance to visit

OUTPUT: None, True, False, or the node’s name as a string

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Name(ast.parse(x).body[0].value)
sage: [vis(n) for n in ['foo', 'bar']]
['foo', 'bar']
sage: [type(vis(n)) for n in ['foo', 'bar']]
[<class 'str'>, <class 'str'>]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Name(ast.parse(x).body[Integer(0)].value)
>>> [vis(n) for n in ['foo', 'bar']]
['foo', 'bar']
>>> [type(vis(n)) for n in ['foo', 'bar']]
[<class 'str'>, <class 'str'>]
visit_NameConstant(node)[source]#

Visit a Python AST ast.NameConstant node.

This is an optimization added in Python 3.4 for the special cases of True, False, and None.

INPUT:

  • node – the node instance to visit

OUTPUT: None, True, False

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_NameConstant(ast.parse(x).body[0].value)
sage: [vis(n) for n in ['True', 'False', 'None']]
[True, False, None]
sage: [type(vis(n)) for n in ['True', 'False', 'None']]
[<class 'bool'>, <class 'bool'>, <class 'NoneType'>]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_NameConstant(ast.parse(x).body[Integer(0)].value)
>>> [vis(n) for n in ['True', 'False', 'None']]
[True, False, None]
>>> [type(vis(n)) for n in ['True', 'False', 'None']]
[<class 'bool'>, <class 'bool'>, <class 'NoneType'>]
visit_Num(node)[source]#

Visit a Python AST ast.Num node.

INPUT:

  • node – the node instance to visit

OUTPUT: the number the node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Num(ast.parse(x).body[0].value)
sage: [vis(n) for n in ['123', '0.0']]
[123, 0.0]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Num(ast.parse(x).body[Integer(0)].value)
>>> [vis(n) for n in ['123', '0.0']]
[123, 0.0]

Note

On Python 3 negative numbers are parsed first, for some reason, as a UnaryOp node.

visit_Str(node)[source]#

Visit a Python AST ast.Str node.

INPUT:

  • node – the node instance to visit

OUTPUT: the string the node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Str(ast.parse(x).body[0].value)
sage: [vis(s) for s in ['"abstract"', "'syntax'", r'''r"tr\ee"''']]
['abstract', 'syntax', 'tr\\ee']

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Str(ast.parse(x).body[Integer(0)].value)
>>> [vis(s) for s in ['"abstract"', "'syntax'", r'''r"tr\ee"''']]
['abstract', 'syntax', 'tr\\ee']
visit_Tuple(node)[source]#

Visit a Python AST ast.Tuple node.

INPUT:

  • node – the node instance to visit

OUTPUT: the tuple the node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_Tuple(ast.parse(x).body[0].value)
sage: [vis(t) for t in ['()', '(x,y)', '("Au", "Al", "Cu")']]
[(), ('x', 'y'), ('Au', 'Al', 'Cu')]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_Tuple(ast.parse(x).body[Integer(0)].value)
>>> [vis(t) for t in ['()', '(x,y)', '("Au", "Al", "Cu")']]
[(), ('x', 'y'), ('Au', 'Al', 'Cu')]
visit_UnaryOp(node)[source]#

Visit a Python AST ast.BinOp node.

INPUT:

  • node – the node instance to visit

OUTPUT: the result that node represents

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: visitor = sms.SageArgSpecVisitor()
sage: vis = lambda x: visitor.visit_UnaryOp(ast.parse(x).body[0].value)
sage: [vis(d) for d in ['+(3*2)', '-(3*2)']]
[6, -6]

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> visitor = sms.SageArgSpecVisitor()
>>> vis = lambda x: visitor.visit_UnaryOp(ast.parse(x).body[Integer(0)].value)
>>> [vis(d) for d in ['+(3*2)', '-(3*2)']]
[6, -6]
visit_arg(node)[source]#

Visit a Python AST ast.arg node.

This node type is only on Python 3, where function arguments are more complex than just an identifier (e.g. they may also include annotations).

For now we simply return the argument identifier as a string.

INPUT:

  • node – the node instance to visit

OUTPUT: the argument name

EXAMPLES:

sage: import ast, sage.misc.sageinspect as sms
sage: s = "def f(a, b=2, c={'a': [4, 5.5, False]}, d=(None, True)):\n    return"
sage: visitor = sms.SageArgSpecVisitor()
sage: args = ast.parse(s).body[0].args.args
sage: [visitor.visit_arg(n) for n in args]
['a', 'b', 'c', 'd']

>>> from sage.all import *
>>> import ast, sage.misc.sageinspect as sms
>>> s = "def f(a, b=2, c={'a': [4, 5.5, False]}, d=(None, True)):\n    return"
>>> visitor = sms.SageArgSpecVisitor()
>>> args = ast.parse(s).body[Integer(0)].args.args
>>> [visitor.visit_arg(n) for n in args]
['a', 'b', 'c', 'd']
sage.misc.sageinspect.formatannotation(annotation, base_module=None)[source]#

This is taken from Python 3.7’s inspect.py; the only change is to add documentation.

INPUT:

  • annotation – annotation for a function

  • base_module – (default: None)

This is only relevant with Python 3, so the doctests are marked accordingly.

EXAMPLES:

sage: from sage.misc.sageinspect import formatannotation
sage: import inspect
sage: def foo(a, *, b:int, **kwargs):
....:     pass
sage: s = inspect.signature(foo)

sage: a = s.parameters['a'].annotation
sage: a
<class 'inspect._empty'>
sage: formatannotation(a)
'inspect._empty'

sage: b = s.parameters['b'].annotation
sage: b
<class 'int'>
sage: formatannotation(b)
'int'

>>> from sage.all import *
>>> from sage.misc.sageinspect import formatannotation
>>> import inspect
>>> def foo(a, *, b:int, **kwargs):
...     pass
>>> s = inspect.signature(foo)

>>> a = s.parameters['a'].annotation
>>> a
<class 'inspect._empty'>
>>> formatannotation(a)
'inspect._empty'

>>> b = s.parameters['b'].annotation
>>> b
<class 'int'>
>>> formatannotation(b)
'int'
sage.misc.sageinspect.is_function_or_cython_function(obj)[source]#

Check whether something is a function.

This is a variant of inspect.isfunction(): We assume that anything which has a genuine __code__ attribute (not using __getattr__ overrides) is a function. This is meant to support Cython functions.

Think twice before using this function (or any function from the inspect or sage.misc.sageinspect modules). Most uses of inspect.isfunction() in ordinary library code can be replaced by callable().

EXAMPLES:

sage: from sage.misc.sageinspect import is_function_or_cython_function
sage: def f(): pass
sage: is_function_or_cython_function(f)
True
sage: is_function_or_cython_function(lambda x:x)
True
sage: from sage.categories.coercion_methods import _mul_parent
sage: is_function_or_cython_function(_mul_parent)
True
sage: is_function_or_cython_function(Integer.digits)     # unbound method
False
sage: is_function_or_cython_function(Integer(1).digits)  # bound method
False

>>> from sage.all import *
>>> from sage.misc.sageinspect import is_function_or_cython_function
>>> def f(): pass
>>> is_function_or_cython_function(f)
True
>>> is_function_or_cython_function(lambda x:x)
True
>>> from sage.categories.coercion_methods import _mul_parent
>>> is_function_or_cython_function(_mul_parent)
True
>>> is_function_or_cython_function(Integer.digits)     # unbound method
False
>>> is_function_or_cython_function(Integer(Integer(1)).digits)  # bound method
False
sage.misc.sageinspect.isclassinstance(obj)[source]#

Check if argument is instance of non built-in class

INPUT:

  • obj – object

EXAMPLES:

sage: from sage.misc.sageinspect import isclassinstance
sage: isclassinstance(int)
False
sage: class myclass: pass
sage: isclassinstance(myclass())
True
sage: isclassinstance(myclass)
False
sage: class mymetaclass(type): pass
sage: class myclass2(metaclass=mymetaclass): pass
sage: isclassinstance(myclass2)
False

>>> from sage.all import *
>>> from sage.misc.sageinspect import isclassinstance
>>> isclassinstance(int)
False
>>> class myclass: pass
>>> isclassinstance(myclass())
True
>>> isclassinstance(myclass)
False
>>> class mymetaclass(type): pass
>>> class myclass2(metaclass=mymetaclass): pass
>>> isclassinstance(myclass2)
False
sage.misc.sageinspect.sage_formatargspec(args, varargs=None, varkw=None, defaults=None, kwonlyargs=(), kwonlydefaults=None, annotations={}, formatarg=<class 'str'>, formatvarargs=None, formatvarkw=None, formatvalue=None, formatreturns=None, formatannotation=None)[source]#

Format an argument spec from the values returned by getfullargspec.

The first seven arguments are (args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations). The other five arguments are the corresponding optional formatting functions that are called to turn names and values into strings. The last argument is an optional function to format the sequence of arguments.

This is taken from Python 3.7’s inspect.py, where it is deprecated. The only change, aside from documentation (this paragraph and the next, plus doctests), is to remove the deprecation warning.

Sage uses this function to format arguments, as obtained by sage_getargspec(). Since sage_getargspec() works for Cython functions while Python’s inspect module does not, it makes sense to keep this function for formatting instances of inspect.FullArgSpec.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_formatargspec
sage: args = ['a', 'b', 'c']
sage: defaults = [3]
sage: sage_formatargspec(args, defaults=defaults)
'(a, b, c=3)'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_formatargspec
>>> args = ['a', 'b', 'c']
>>> defaults = [Integer(3)]
>>> sage_formatargspec(args, defaults=defaults)
'(a, b, c=3)'
sage.misc.sageinspect.sage_getargspec(obj)[source]#

Return the names and default values of a function’s arguments.

INPUT:

  • obj – any callable object

OUTPUT:

A named tuple FullArgSpec is returned, as specified by the Python library function inspect.getfullargspec().

NOTE:

If the object has a method _sage_argspec_, then the output of that method is transformed into a named tuple and then returned.

If a class instance has a method _sage_src_, then its output is studied to determine the argspec. This is because currently the CachedMethod decorator has no _sage_argspec_ method.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getargspec
sage: def f(x, y, z=1, t=2, *args, **keywords):
....:     pass
sage: sage_getargspec(f)
FullArgSpec(args=['x', 'y', 'z', 't'], varargs='args', varkw='keywords',
            defaults=(1, 2), kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getargspec
>>> def f(x, y, z=Integer(1), t=Integer(2), *args, **keywords):
...     pass
>>> sage_getargspec(f)
FullArgSpec(args=['x', 'y', 'z', 't'], varargs='args', varkw='keywords',
            defaults=(1, 2), kwonlyargs=[], kwonlydefaults=None, annotations={})

We now run sage_getargspec on some functions from the Sage library:

sage: sage_getargspec(identity_matrix)                                          # needs sage.modules
FullArgSpec(args=['ring', 'n', 'sparse'], varargs=None, varkw=None,
            defaults=(0, False), kwonlyargs=[], kwonlydefaults=None,
            annotations={})
sage: sage_getargspec(factor)
FullArgSpec(args=['n', 'proof', 'int_', 'algorithm', 'verbose'],
            varargs=None, varkw='kwds', defaults=(None, False, 'pari', 0),
            kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> sage_getargspec(identity_matrix)                                          # needs sage.modules
FullArgSpec(args=['ring', 'n', 'sparse'], varargs=None, varkw=None,
            defaults=(0, False), kwonlyargs=[], kwonlydefaults=None,
            annotations={})
>>> sage_getargspec(factor)
FullArgSpec(args=['n', 'proof', 'int_', 'algorithm', 'verbose'],
            varargs=None, varkw='kwds', defaults=(None, False, 'pari', 0),
            kwonlyargs=[], kwonlydefaults=None, annotations={})

In the case of a class or a class instance, the FullArgSpec of the __new__, __init__ or __call__ method is returned:

sage: P.<x,y> = QQ[]
sage: sage_getargspec(P)                                                        # needs sage.libs.singular
FullArgSpec(args=['base_ring', 'n', 'names', 'order'],
            varargs=None, varkw=None, defaults=('degrevlex',),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
sage: sage_getargspec(P.__class__)                                              # needs sage.libs.singular
FullArgSpec(args=['self', 'x'], varargs='args', varkw='kwds', defaults=(0,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> P = QQ['x, y']; (x, y,) = P._first_ngens(2)
>>> sage_getargspec(P)                                                        # needs sage.libs.singular
FullArgSpec(args=['base_ring', 'n', 'names', 'order'],
            varargs=None, varkw=None, defaults=('degrevlex',),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
>>> sage_getargspec(P.__class__)                                              # needs sage.libs.singular
FullArgSpec(args=['self', 'x'], varargs='args', varkw='kwds', defaults=(0,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})

The following tests against various bugs that were fixed in Issue #9976:

sage: from sage.rings.polynomial.real_roots import bernstein_polynomial_factory_ratlist     # needs sage.modules
sage: sage_getargspec(bernstein_polynomial_factory_ratlist.coeffs_bitsize)                  # needs sage.modules
FullArgSpec(args=['self'], varargs=None, varkw=None, defaults=None,
            kwonlyargs=[], kwonlydefaults=None, annotations={})
sage: from sage.rings.polynomial.pbori.pbori import BooleanMonomialMonoid       # needs sage.rings.polynomial.pbori
sage: sage_getargspec(BooleanMonomialMonoid.gen)                                # needs sage.rings.polynomial.pbori
FullArgSpec(args=['self', 'i'], varargs=None, varkw=None, defaults=(0,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
sage: I = P*[x,y]
sage: sage_getargspec(I.groebner_basis)                                         # needs sage.libs.singular
FullArgSpec(args=['self', 'algorithm', 'deg_bound', 'mult_bound', 'prot'],
            varargs='args', varkw='kwds', defaults=('', None, None, False),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
sage: cython("cpdef int foo(x,y) except -1: return 1")                          # needs sage.misc.cython
sage: sage_getargspec(foo)                                                      # needs sage.misc.cython
FullArgSpec(args=['x', 'y'], varargs=None, varkw=None, defaults=None,
            kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> from sage.rings.polynomial.real_roots import bernstein_polynomial_factory_ratlist     # needs sage.modules
>>> sage_getargspec(bernstein_polynomial_factory_ratlist.coeffs_bitsize)                  # needs sage.modules
FullArgSpec(args=['self'], varargs=None, varkw=None, defaults=None,
            kwonlyargs=[], kwonlydefaults=None, annotations={})
>>> from sage.rings.polynomial.pbori.pbori import BooleanMonomialMonoid       # needs sage.rings.polynomial.pbori
>>> sage_getargspec(BooleanMonomialMonoid.gen)                                # needs sage.rings.polynomial.pbori
FullArgSpec(args=['self', 'i'], varargs=None, varkw=None, defaults=(0,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
>>> I = P*[x,y]
>>> sage_getargspec(I.groebner_basis)                                         # needs sage.libs.singular
FullArgSpec(args=['self', 'algorithm', 'deg_bound', 'mult_bound', 'prot'],
            varargs='args', varkw='kwds', defaults=('', None, None, False),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
>>> cython("cpdef int foo(x,y) except -1: return 1")                          # needs sage.misc.cython
>>> sage_getargspec(foo)                                                      # needs sage.misc.cython
FullArgSpec(args=['x', 'y'], varargs=None, varkw=None, defaults=None,
            kwonlyargs=[], kwonlydefaults=None, annotations={})

If a functools.partial() instance is involved, we see no other meaningful solution than to return the argspec of the underlying function:

sage: def f(a, b, c, d=1):
....:     return a + b + c + d
sage: import functools
sage: f1 = functools.partial(f, 1, c=2)
sage: sage_getargspec(f1)
FullArgSpec(args=['a', 'b', 'c', 'd'], varargs=None, varkw=None, defaults=(1,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})

>>> from sage.all import *
>>> def f(a, b, c, d=Integer(1)):
...     return a + b + c + d
>>> import functools
>>> f1 = functools.partial(f, Integer(1), c=Integer(2))
>>> sage_getargspec(f1)
FullArgSpec(args=['a', 'b', 'c', 'd'], varargs=None, varkw=None, defaults=(1,),
            kwonlyargs=[], kwonlydefaults=None, annotations={})
sage.misc.sageinspect.sage_getdef(obj, obj_name='')[source]#

Return the definition header for any callable object.

INPUT:

  • obj – function

  • obj_name – string (default: ‘’)

obj_name is prepended to the output.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getdef
sage: sage_getdef(identity_matrix)                                              # needs sage.modules
'(ring, n=0, sparse=False)'
sage: sage_getdef(identity_matrix, 'identity_matrix')                           # needs sage.modules
'identity_matrix(ring, n=0, sparse=False)'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getdef
>>> sage_getdef(identity_matrix)                                              # needs sage.modules
'(ring, n=0, sparse=False)'
>>> sage_getdef(identity_matrix, 'identity_matrix')                           # needs sage.modules
'identity_matrix(ring, n=0, sparse=False)'

Check that Issue #6848 has been fixed:

sage: sage_getdef(RDF.random_element)
'(min=-1, max=1)'

>>> from sage.all import *
>>> sage_getdef(RDF.random_element)
'(min=-1, max=1)'

If an exception is generated, None is returned instead and the exception is suppressed.

sage.misc.sageinspect.sage_getdoc(obj, obj_name='', embedded=False)[source]#

Return the docstring associated to obj as a string.

If obj is a Cython object with an embedded position in its docstring, the embedded position is stripped.

The optional boolean argument embedded controls the string formatting. It is False by default.

INPUT:

  • obj – a function, module, etc.: something with a docstring.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getdoc
sage: sage_getdoc(identity_matrix)[87:124]                                      # needs sage.modules
'Return the n x n identity matrix over'
sage: def f(a,b,c,d=1): return a+b+c+d
...
sage: import functools
sage: f1 = functools.partial(f, 1,c=2)
sage: f.__doc__ = "original documentation"
sage: f1.__doc__ = "specialised documentation"
sage: sage_getdoc(f)
'original documentation\n'
sage: sage_getdoc(f1)
'specialised documentation\n'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getdoc
>>> sage_getdoc(identity_matrix)[Integer(87):Integer(124)]                                      # needs sage.modules
'Return the n x n identity matrix over'
>>> def f(a,b,c,d=Integer(1)): return a+b+c+d
...
>>> import functools
>>> f1 = functools.partial(f, Integer(1),c=Integer(2))
>>> f.__doc__ = "original documentation"
>>> f1.__doc__ = "specialised documentation"
>>> sage_getdoc(f)
'original documentation\n'
>>> sage_getdoc(f1)
'specialised documentation\n'
sage.misc.sageinspect.sage_getdoc_original(obj)[source]#

Return the unformatted docstring associated to obj as a string.

If obj is a Cython object with an embedded position or signature in its docstring, the embedded information is stripped. If the stripped docstring is empty, then the stripped docstring of obj.__init__ is returned instead.

Feed the results from this into the function sage.misc.sagedoc.format() for printing to the screen.

INPUT:

  • obj – a function, module, etc.: something with a docstring.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getdoc_original

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getdoc_original

Here is a class that has its own docstring:

sage: print(sage_getdoc_original(sage.rings.integer.Integer))

    The :class:`Integer` class represents arbitrary precision
    integers. It derives from the :class:`Element` class, so
    integers can be used as ring elements anywhere in Sage.
...

>>> from sage.all import *
>>> print(sage_getdoc_original(sage.rings.integer.Integer))
<BLANKLINE>
    The :class:`Integer` class represents arbitrary precision
    integers. It derives from the :class:`Element` class, so
    integers can be used as ring elements anywhere in Sage.
...

If the class does not have a docstring, the docstring of the __init__ method is used, but not the __init__ method of the base class (this was fixed in Issue #24936):

sage: from sage.categories.category import Category
sage: class A(Category):
....:     def __init__(self):
....:         '''The __init__ docstring'''
sage: sage_getdoc_original(A)
'The __init__ docstring'
sage: class B(Category):
....:     pass
sage: sage_getdoc_original(B)
''

>>> from sage.all import *
>>> from sage.categories.category import Category
>>> class A(Category):
...     def __init__(self):
...         '''The __init__ docstring'''
>>> sage_getdoc_original(A)
'The __init__ docstring'
>>> class B(Category):
...     pass
>>> sage_getdoc_original(B)
''

Old-style classes are supported:

sage: class OldStyleClass:
....:     def __init__(self):
....:         '''The __init__ docstring'''
....:         pass
sage: print(sage_getdoc_original(OldStyleClass))
The __init__ docstring

>>> from sage.all import *
>>> class OldStyleClass:
...     def __init__(self):
...         '''The __init__ docstring'''
...         pass
>>> print(sage_getdoc_original(OldStyleClass))
The __init__ docstring

When there is no __init__ method, we just get an empty string:

sage: class OldStyleClass:
....:     pass
sage: sage_getdoc_original(OldStyleClass)
''

>>> from sage.all import *
>>> class OldStyleClass:
...     pass
>>> sage_getdoc_original(OldStyleClass)
''

If an instance of a class does not have its own docstring, the docstring of its class results:

sage: sage_getdoc_original(sage.plot.colors.aliceblue) == sage_getdoc_original(sage.plot.colors.Color)          # needs sage.plot
True

>>> from sage.all import *
>>> sage_getdoc_original(sage.plot.colors.aliceblue) == sage_getdoc_original(sage.plot.colors.Color)          # needs sage.plot
True
sage.misc.sageinspect.sage_getfile(obj)[source]#

Get the full file name associated to obj as a string.

INPUT:

  • obj – a Sage object, module, etc.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getfile
sage: sage_getfile(sage.rings.rational)
'...sage/rings/rational.pyx'
sage: from sage.algebras.steenrod.steenrod_algebra import Sq                    # needs sage.combinat sage.modules
sage: sage_getfile(Sq)                                                          # needs sage.combinat sage.modules
'...sage/algebras/steenrod/steenrod_algebra.py'
sage: sage_getfile(x)                                                           # needs sage.symbolic
'...sage/symbolic/expression.pyx'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getfile
>>> sage_getfile(sage.rings.rational)
'...sage/rings/rational.pyx'
>>> from sage.algebras.steenrod.steenrod_algebra import Sq                    # needs sage.combinat sage.modules
>>> sage_getfile(Sq)                                                          # needs sage.combinat sage.modules
'...sage/algebras/steenrod/steenrod_algebra.py'
>>> sage_getfile(x)                                                           # needs sage.symbolic
'...sage/symbolic/expression.pyx'

The following tests against some bugs fixed in Issue #9976:

sage: obj = sage.combinat.partition_algebra.SetPartitionsAk                     # needs sage.combinat sage.modules
sage: sage_getfile(obj)                                                         # needs sage.combinat sage.modules
'...sage/combinat/partition_algebra.py'

>>> from sage.all import *
>>> obj = sage.combinat.partition_algebra.SetPartitionsAk                     # needs sage.combinat sage.modules
>>> sage_getfile(obj)                                                         # needs sage.combinat sage.modules
'...sage/combinat/partition_algebra.py'

And here is another bug, fixed in Issue #11298:

sage: P.<x,y> = QQ[]
sage: sage_getfile(P)                                                           # needs sage.libs.singular
'...sage/rings/polynomial/multi_polynomial_libsingular...'

>>> from sage.all import *
>>> P = QQ['x, y']; (x, y,) = P._first_ngens(2)
>>> sage_getfile(P)                                                           # needs sage.libs.singular
'...sage/rings/polynomial/multi_polynomial_libsingular...'

A problem fixed in Issue #16309:

sage: cython(                                                                   # needs sage.misc.cython
....: '''
....: class Bar: pass
....: cdef class Foo: pass
....: ''')
sage: sage_getfile(Bar)                                                         # needs sage.misc.cython
'...pyx'
sage: sage_getfile(Foo)                                                         # needs sage.misc.cython
'...pyx'

>>> from sage.all import *
>>> cython(                                                                   # needs sage.misc.cython
... '''
... class Bar: pass
... cdef class Foo: pass
... ''')
>>> sage_getfile(Bar)                                                         # needs sage.misc.cython
'...pyx'
>>> sage_getfile(Foo)                                                         # needs sage.misc.cython
'...pyx'

By Issue #18249, we return an empty string for Python builtins. In that way, there is no error when the user types, for example, range?:

sage: sage_getfile(range)
''

>>> from sage.all import *
>>> sage_getfile(range)
''
sage.misc.sageinspect.sage_getfile_relative(obj)[source]#

Get the file name associated to obj as a string.

This is the same as sage_getfile(), but if the source file is part of the sage.* namespace, it makes the file name relative so that it starts with sage/.

INPUT:

  • obj – a Sage object, module, etc.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getfile_relative
sage: sage_getfile_relative(sage.rings.rational)
'sage/rings/rational.pyx'
sage: from sage.algebras.steenrod.steenrod_algebra import Sq                    # needs sage.combinat sage.modules
sage: sage_getfile_relative(Sq)                                                 # needs sage.combinat sage.modules
'sage/algebras/steenrod/steenrod_algebra.py'
sage: sage_getfile_relative(x)                                                  # needs sage.symbolic
'sage/symbolic/expression.pyx'
sage: sage_getfile_relative(range)
''

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getfile_relative
>>> sage_getfile_relative(sage.rings.rational)
'sage/rings/rational.pyx'
>>> from sage.algebras.steenrod.steenrod_algebra import Sq                    # needs sage.combinat sage.modules
>>> sage_getfile_relative(Sq)                                                 # needs sage.combinat sage.modules
'sage/algebras/steenrod/steenrod_algebra.py'
>>> sage_getfile_relative(x)                                                  # needs sage.symbolic
'sage/symbolic/expression.pyx'
>>> sage_getfile_relative(range)
''
sage.misc.sageinspect.sage_getsource(obj)[source]#

Return the source code associated to obj as a string, or None.

INPUT:

  • obj – function, etc.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getsource
sage: sage_getsource(identity_matrix)[19:60]                                    # needs sage.modules
'identity_matrix(ring, n=0, sparse=False):'
sage: sage_getsource(identity_matrix)[19:60]                                    # needs sage.modules
'identity_matrix(ring, n=0, sparse=False):'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getsource
>>> sage_getsource(identity_matrix)[Integer(19):Integer(60)]                                    # needs sage.modules
'identity_matrix(ring, n=0, sparse=False):'
>>> sage_getsource(identity_matrix)[Integer(19):Integer(60)]                                    # needs sage.modules
'identity_matrix(ring, n=0, sparse=False):'
sage.misc.sageinspect.sage_getsourcelines(obj)[source]#

Return a pair ([source_lines], starting line number) of the source code associated to obj, or None.

INPUT:

  • obj – function, etc.

OUTPUT:

(source_lines, lineno) or None: source_lines is a list of strings, and lineno is an integer.

EXAMPLES:

sage: from sage.misc.sageinspect import sage_getsourcelines

sage: # needs sage.modules
sage: sage_getsourcelines(matrix)[1]
21
sage: sage_getsourcelines(matrix)[0][0]
'def matrix(*args, **kwds):\n'

>>> from sage.all import *
>>> from sage.misc.sageinspect import sage_getsourcelines

>>> # needs sage.modules
>>> sage_getsourcelines(matrix)[Integer(1)]
21
>>> sage_getsourcelines(matrix)[Integer(0)][Integer(0)]
'def matrix(*args, **kwds):\n'

Some classes customize this using a _sage_src_lines_ method, which gives the source lines of a class instance, but not the class itself. We demonstrate this for CachedFunction:

sage: # needs sage.combinat
sage: cachedfib = cached_function(fibonacci)
sage: sage_getsourcelines(cachedfib)[0][0]
'def fibonacci(n, algorithm="pari") -> Integer:\n'
sage: sage_getsourcelines(type(cachedfib))[0][0]
'cdef class CachedFunction():\n'

>>> from sage.all import *
>>> # needs sage.combinat
>>> cachedfib = cached_function(fibonacci)
>>> sage_getsourcelines(cachedfib)[Integer(0)][Integer(0)]
'def fibonacci(n, algorithm="pari") -> Integer:\n'
>>> sage_getsourcelines(type(cachedfib))[Integer(0)][Integer(0)]
'cdef class CachedFunction():\n'
sage.misc.sageinspect.sage_getvariablename(self, omit_underscore_names=True)[source]#

Attempt to get the name of a Sage object.

INPUT:

  • self – any object.

  • omit_underscore_names – boolean, default True.

OUTPUT:

If the user has assigned an object obj to a variable name, then return that variable name. If several variables point to obj, return a sorted list of those names. If omit_underscore_names is True (the default) then omit names starting with an underscore “_”.

EXAMPLES:

sage: # needs sage.modules
sage: from sage.misc.sageinspect import sage_getvariablename
sage: A = random_matrix(ZZ, 100)
sage: sage_getvariablename(A)
'A'
sage: B = A
sage: sage_getvariablename(A)
['A', 'B']

>>> from sage.all import *
>>> # needs sage.modules
>>> from sage.misc.sageinspect import sage_getvariablename
>>> A = random_matrix(ZZ, Integer(100))
>>> sage_getvariablename(A)
'A'
>>> B = A
>>> sage_getvariablename(A)
['A', 'B']

If an object is not assigned to a variable, an empty list is returned:

sage: sage_getvariablename(random_matrix(ZZ, 60))                               # needs sage.modules
[]

>>> from sage.all import *
>>> sage_getvariablename(random_matrix(ZZ, Integer(60)))                               # needs sage.modules
[]