On 02/15/2018 11:55 PM, Nick Coghlan wrote:
On 16 February 2018 at 12:19, rym...@gmail.com wrote:
I don't know...to me this looks downright ugly and an awkward special case.
It feels like it combines reading difficulty of inline assignment with the
awkwardness of a magic word and the ugliness of using ?. Basically, every
con of the other proposals combined...
Yeah, it's tricky to find a spelling that looks nice without being
readily confusable with other existing constructs (most notably
keyword arguments).
The cleanest *looking* idea I've come up with would be to allow
arbitrary embedded assignments to ordinary frame local variables using
the "(expr as name)" construct:
-1 to ?it
+1 to (name as expr)
However, while I think that looks nicer in general, we'd still have to
choose between two surprising behaviours:
* implicitly delete the statement locals after the statement where
they're set (which still overwrites any values previously bound to
those names, similar to what happens with exception clauses)
If we're overwriting locals anyway, don't delete it. The good reason for
unsetting an exception variable doesn't apply here.
* skip deleting, which means references to subexpressions may last
longer than expected (and we'd have the problem where embedded
assignments could overwrite existing local variables)
Odds are good that we'll want/need that assignment even after the immediate
expression it's used in. Let it stick around.
--
~Ethan~
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