Function objects are created by function definitions. The only
operation on a function object is to call it:
func(argument-list)
.
There are really two flavors of function objects: built-in functions and user-defined functions. Both support the same operation (to call the function), but the implementation is different, hence the different object types.
The implementation adds two special read-only attributes:
f.func_code
is a function's code
object (see below) and f.func_globals
is
the dictionary used as the function's global namespace (this is the
same as m.__dict__
where m is the module in which
the function f was defined).
Function objects also support getting and setting arbitrary attributes, which can be used, for example, to attach metadata to functions. Regular attribute dot-notation is used to get and set such attributes. Note that the current implementation only supports function attributes on user-defined functions. Function attributes on built-in functions may be supported in the future.
Functions have another special attribute f.__dict__
(a.k.a. f.func_dict
) which contains the namespace used to
support function attributes. __dict__
and func_dict
can
be accessed directly or set to a dictionary object. A function's
dictionary cannot be deleted.
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