Code style

Dragonfly’s code base generally follows the PEP 8 Style Guide for Python Code. There are some parts of Dragonfly that don’t follow that guide precisely, which is okay; it is only a guideline and blind adherence to it can actually be bad sometimes (see PEP 8 A Foolish Consistency is the Hobgoblin of Little Minds).

When making code submissions for Dragonfly, try to generally stick to the PEP 8 style guide.

Dragonfly’s source files have historically had a maximum line length of 76 characters, although up to 85 characters is fine (PEP 8). The exception to this rule is where a long URL is used in a comment or string. Long URLs should usually be on separate lines.

Documentation style

Most docstrings in Dragonfly generally follow the Sphinx docstring format. A different style is used in some places, mostly for constructor arguments:

class Grammar(object):
      Grammar class for managing a set of rules.

      Constructor arguments:
       - *name* -- name of this grammar
       - *description* (str, default: None) --
         description for this grammar
       - *context* (Context, default: None) --
         context within which to be active.  If *None*, the grammar will
         always be active.


The Sphinx docstring format is preferred, although the above format is also acceptable. The important thing is that the documentation is readable in the source file and in the various generated formats (e.g. HTML, PDF, man page).

Notice that the docstring’s content is also indented. This is done in a few places and is also acceptable.