28.3. __builtin__ — Built-in objects¶

This module provides direct access to all ‘built-in’ identifiers of Python; for example, __builtin__.open is the full name for the built-in function open(). See Built-in Functions and Built-in Constants for documentation.

This module is not normally accessed explicitly by most applications, but can be useful in modules that provide objects with the same name as a built-in value, but in which the built-in of that name is also needed. For example, in a module that wants to implement an open() function that wraps the built-in open(), this module can be used directly:

import __builtin__
def open(path):
 f = __builtin__.open(path, 'r')
 return UpperCaser(f)
class UpperCaser:
 '''Wrapper around a file that converts output to upper-case.'''
 def __init__(self, f):
 self._f = f
 def read(self, count=-1):
 return self._f.read(count).upper()
 # ...

CPython implementation detail: Most modules have the name __builtins__ (note the 's') made available as part of their globals. The value of __builtins__ is normally either this module or the value of this modules’s __dict__ attribute. Since this is an implementation detail, it may not be used by alternate implementations of Python.