Examples

Here are some examples to get you started on usage of Altered States:

I/O redirection

>>> import sys
>>> from StringIO import StringIO
>>> from altered import state
>>> buf = StringIO()
>>> with(state(sys, stdout=buf)):
...     print 'foo'
>>> buf.getvalue()
'foo\n'

Faking an import

>>> import sys
>>> from altered import state, Expando
>>> with(state(sys.modules, fakey=Expando(foo='bar') )):
...     import fakey
...     print fakey.foo
bar

In-place patching

Module scope

>>> @state(globals(), injected='foo')
... def fn():
...     return injected
>>> fn()
'foo'

Local scope

>>> from altered import state, E
>>> with state(vars(), injected='foo'):
...    print injected
foo

Deny the existance of a module

It’d be much better if it would raise `ImportError` here. Maybee later.

>>> import sys
>>> from altered import state, forget
>>> with(state(sys.modules, shutil=forget)):
...     import shutil
Traceback (most recent call last):
KeyError: 'shutil'
>>> import shutil

Nested structure

>>> from altered import state, Expando
>>> ctx = Expando()
>>> idx = 0
>>> users = [Expando(name='Foo', get_token=lambda: 'xyz')]
>>> @state(ctx, users=users)
... def token(idx):
...     return ctx.users[idx].get_token()
>>> token(0)
'xyz'