[Python-Dev] [Python-ideas] Proposed addtion to urllib.parse in 3.1 (and urlparse in 2.7)
mrts.pydev at gmail.com
Sun Apr 19 10:38:05 CEST 2009
On Sun, Apr 19, 2009 at 2:06 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> That said, I'm starting to wonder if an even better option may be to
> just drop the kwargs support from the function and require people to
> always supply a parameters dictionary. That would simplify the signature
> to the quite straightforward:
> def add_query_params(url, params, allow_dups=True, sep='&')
That's the most straightforward and I like this more than the one below.
> I agree that isn't a good option, but mapping True/False/None to those
> specific behaviours also seems rather arbitrary (specifically, it is
> difficult to remember which of "allow_dups=False" and "allow_dups=None"
> means to ignore any duplicate keys and which means to ignore only
> duplicate items).
I'd say it's less of a problem when using named arguments, i.e. you read it as:
allow_dups=True : yes
allow_dups=False : effeminately no :),
allow_dups=None : strictly no
which more or less corresponds to the behaviour.
> It also doesn't provide a clear mechanism for
> extension (e.g. what if someone wanted duplicate params to trigger an
> Perhaps the extra argument should just be a key/value pair filtering
> function, and we provide functions for the three existing behaviours
> (i.e. allow_duplicates(), ignore_duplicate_keys(),
> ignore_duplicate_items()) in the urllib.parse module.
This would be the most flexible and conceptually right (ye olde
strategy pattern), but would clutter the API.
> Note that your implementation and docstring currently conflict with each
> other - the docstring says "pass them via a dictionary in second
> argument:" but the dictionary is currently the third argument (the
> docstring also later refers to passing OrderedDictionary as the second
It's a mistake that exemplifies once again that positional args are awkward :).
So, gentlemen, either
def add_query_params(url, params, allow_dups=True, sep='&')
def add_query_params(url, params, strategy=allow_duplicates, sep='&')
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