coding-standard.txt

= Divmod Coding Standard =

Divmod uses [http://twistedmatrix.com/trac/browser/trunk/doc/development/policy/coding-standard.xhtml?format=raw the Twisted coding standard].

In addition, we are trying to make certain aspects of the Twisted coding standard stricter.  For example:

 * There should be 3 blank lines between module-level suites, such as classes and top-level functions.
 * There should be 2 blank lines between class-level suites, such as methods.
 * Within a class, the ordering of the elements is:
    1. docstring
    1. {{{implements()}}}
    1. class attributes
    1. Python special methods, starting with {{{__new__}}} if present, then {{{__init__}}}.
    1. Methods part of no interface
    1. Methods implementing an interface, grouped by interface, prefixed with a comment like this:
{{{
#!python
# IYourInterface
}}}
 * Be careful with code like:
{{{
#!python
def test():
    outer1, outer2 = something()
    class Stub(object):
        foo = frob(outer1)
        def bar(self):
            return outer2
}}}
   Due to [http://bugs.python.org/issue1569356 a bug] in Python ≤ 2.5, when run with tracing (such as `trial --coverage`), the closed bindings (`outer1`, `outer2`) leak into the class context, causing problems when they have special meaning there.[[BR]]
   Vulnerable names should be renamed to avoid conflict.  Vulnerable ''values'' require wrapping in an indirect reference, such as:
{{{
#!python
    class Foo(formless.TypedInterface):
        pass
    _indirectFoo = lambda: Foo
    class Bar(formless.TypedInterface):
        baz = formless.Object(interface=_indirectFoo())
}}}
   See also #2394.