PEP 308: Pep Update

[Raymond Hettinger]

Amended the PEP to reflect some convergence on the newsgroup:

* Listed the downsides of the current proposal.

* Listed why '<cond> then <expr1> else <expr2>' is starting to
   be preferred over '<cond> and <expr1> or <expr2>'.

* After BDFL comments, I withdrew my c??a||b syntax
   and deleted the rejected c?a!b syntax.  The remaining
   punctuation based contender is c?a:b.

* After BDFL rejection of non-short-circuiting options,
   advocacy dropped sharply.  Removed it from the list of
   contenders.

The leading options on the table are:

*     (if <cond>: <expr1> else: >expr2>)
*     <cond> then <expr1> else <expr2>
*     <cond> ? <expr1> : <expr2>
*     no change


Raymond Hettinger