[Python-Dev] [Python-ideas] Proposed addtion to urllib.parse in 3.1 (and urlparse in 2.7) (original) (raw)

Steven Bethard steven.bethard at gmail.com
Sun Apr 19 17:54:12 CEST 2009

On Sun, Apr 19, 2009 at 1:38 AM, Mart Sõmermaa <mrts.pydev at gmail.com> wrote:

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 addqueryparams(url, params, allowdups=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 "allowdups=False" and "allowdups=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: allowdups=True : yes allowdups=False : effeminately no :), allowdups=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 exception?) Perhaps the extra argument should just be a key/value pair filtering function, and we provide functions for the three existing behaviours (i.e. allowduplicates(), ignoreduplicatekeys(), ignoreduplicateitems()) 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 argument). It's a mistake that exemplifies once again that positional args are awkward :). --- So, gentlemen, either def addqueryparams(url, params, allowdups=True, sep='&') or def allowduplicates(...) def removeduplicatevalues(...) ... def addqueryparams(url, params, strategy=allowduplicates, sep='&')

+1 for the strategy approach.

Steve

I'm not in-sane. Indeed, I am so far out of sane that you appear a tiny blip on the distant coast of sanity. --- Bucky Katt, Get Fuzzy

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