[Python-3000] No Container Literals

[Nick Coghlan]

Calvin Spealman wrote:
> Just throwing this out there, but I would love to see a complete
> dropping of container literals from Python. That is why I proposed the
> coercion syntax (ex: list from something) because it would allow
> things like list(1, 2, 3) and we can already do dict(ten=10,
> eleven=11), so what is the real need for literals as they are? With
> some proper compiler optimization we can deduce if list, dict, and
> such are in fact bound to the builtins we know, and build literals
> from these expressions just the same, but I feel they seem much more
> readable, and allow better addition of more literal compilations (set
> literals are fixed then, for example). I know no one will like this,
> but I have to make the idea known anyway.

To turn the idea around a bit, could that *syntax* be a way to get rid of the 
plethora of parentheses in set literals?

That is,

   NAME from TUPLE

Would be equivalent to:

   NAME((TUPLE))

To avoid the ambiguity problems suffered string % formatting, the item on the 
right would have to be a tuple (with a single value without a trailing comma 
being either implicitly converted to a singleton tuple or else raising a 
syntax error).

So instead of 'set((1, 2, 3))' you could write 'set from 1, 2, 3'.

This would be usable for any function that took an iterable as its sole 
required argument.

Instead of writing:

   if any((a, b, c)):
       # Do something

You could write:

   if any from a, b, c:
       # Do something

I don't personally think there's sufficient payoff in readability to justify 
the duplication of functionality, but figured I'd put the idea out there anyway.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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