We had some discussion recently about reforming the for-loop syntax
since we'll be switching it to external iterators and it's a bit
deceptive to the user to be writing a lambda-pattern there.
Have we yet considered C++11's approach to this?
for <name> : <expr> { ... }
This seems pretty consistent to me at first glance, considering how we
use a similar syntax to declare and initialize fields. Consider <name>
being initialized by <expr> for each value in <expr>.
- No-pattern form now requires a dummy pattern. That is, we can't do:
for 10.times { ... }
anymore, rather we have to write:
for _ in 10.times() { ... }
If we do go this route, I think this new idiom is actually a good thing.
`for 10.times { }` seems a bit too clever, whereas the latter is
entirely predictable, albeit slightly more verbose.; it's also entirely
consistent with our usage of _ elsewhere. What would be the trait tied
to 'in' that allowed any user-created container to be iterated in this
manner?
I found it more interesting to note that, should we take 'in' as a new
keyword, it's a perfectly reasonable keyword to reuse for the putative
"allocation expressions" we've been talking about needing for
supporting C++-like placement-new.
That's a really good idea and seems entirely logical, coming from C++.
J
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