I always thought the builtin objects were those we can get from the
`builtins` module, that is those always available. In fact the "Built-in
Functions" documentation:
https://docs.python.org/3/library/functions.html
says: """The Python interpreter has a number of functions and types
built into it that are always available. They are listed here in
alphabetical order""". The functions in the documentation list, as
expected, are the same functions we get from the `builtins` module.
Now, is `math.sin` builtin? Of course not, because it is not an
attribute of builtins:
>>> import builtins
>>> hasattr(builtins, 'sin')
False
and in fact it is not always available:
>>> sin
Traceback (most recent call last):
...
NameError: name 'sin' is not defined
But what happens if I want to check by using `inspect.isbuiltin()`? The
answer surprises me:
>>> import inspect
>>> print(inspect.isbuiltin.__doc__.split('\n')[0])
Return true if the object is a built-in function or method.
>>> import math
>>> inspect.isbuiltin(math.sin)
True
That's because the term "built-in" here means "written in C", as
explained in the doc:
https://docs.python.org/3/library/types.html#types.BuiltinMethodType
So, we have built-in objects that are always available, whose names live
in the builtin namespace, and other built-in objects that do not live in
the builtin namespace :/ By using the same word (built-in) to indicate
either objects written in C or objects referenced by the builtin
namespace could be a bit muddler for everyone, beginner or not. Is it
too late for changing the name of the `builtin` namespace in something
like, for instance, `root` namespace, or using the name "core"
(inspect.iscore(), types.CoreFunctionType, ecc.) to indicate "written in
C or whatever underlying language"?
--
Marco Buttu
INAF-Osservatorio Astronomico di Cagliari
Via della Scienza n. 5, 09047 Selargius (CA)
Phone: 070 711 80 217
Email: mbu...@oa-cagliari.inaf.it
--
https://mail.python.org/mailman/listinfo/python-list
