Brett Cannon wrote:
On Mon, Jan 19, 2009 at 19:02, Scott Dial
<scott+python-...@scottdial.com> wrote:
Brett Cannon wrote:
3. Are brackets for optional arguments (e.g. ``def fxn(a [, b=None [,
c=None]])``) really necessary when default argument values are
present? And do we really need to nest the brackets when it is obvious
that having on optional argument means the rest are optional as well?
I can't think of an example off the top of my head, but I'm certain the
point of nesting the brackets is to delimit the optional arguments into
groups. Documenting your fxn() examples as "fxn(a [, b=None, c=None])"
would imply that if you provide 'b' then you must provide 'c', or if we
abandon nested brackets, it's ambiguous as to the requirements. Imagine
seeing "foo(a [, b=None, c=None [, d=None]])" and I think the rationale
for such notation becomes clear.
Well, that is such a rare case that I don't know if it warrants the
line noise in the argument declaration. That argument also doesn't
make sense in the face of ``fxn(a [, a=None [, b=None]])`` where 'b'
almost always has no connection to 'a', but is still supposed to be
listed that way because of positional arguments being optional. I
understand using them for C functions where there is no such thing as
a default argument, but it just doesn't make a ton of sense for Python
code. I don't know of anyone who was confused by what help() spit out
and not having fancy bracketing.
I think the square bracketing is ugly and does nothing for clarity or
readability. The sooner it can be phased out the better.
Function annotations should probably only be used in API descriptions
where those annotations actually exist - otherwise when there are real
annotations you have a conflict on how to indicate that in the
documentation.
Michael
-Brett
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