[Python-Dev] syntactic support for sets (original) (raw)

Ronald Oussoren ronaldoussoren at mac.com
Mon Feb 6 15:36:06 CET 2006

On Monday, February 06, 2006, at 03:12PM, Donovan Baarda <abo at minkirri.apana.org.au> wrote:

On Fri, 2006-02-03 at 20:02 +0100, "Martin v. Löwis" wrote:

Donovan Baarda wrote: > Before set() the standard way to do them was to use dicts with None > Values... to me the "{1,2,3}" syntax would have been a logical extension > of the "a set is a dict with no values, only keys" mindset. I don't know > why it wasn't done this way in the first place, though I missed the > arguments where it was rejected.

There might be many reasons; one obvious reason is that you can't spell the empty set that way. Hmm... how about "{,}", which is the same trick tuples use for the empty tuple?

Isn't () the empty tuple? I guess you're confusing this with a single element tuple: (1,) instead of (1) (well actually it is "1,")

BTW. I don't like your proposal for spelling the empty set as {,} because that is entirely non-obvious. If {1,2,3} where a valid way to spell a set literal, I'd expect {} for the empty set.

Ronald

-- Donovan Baarda <abo at minkirri.apana.org.au> http://minkirri.apana.org.au/~abo/

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