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Postings from October 2015
* Abigail <abigail@abigail.be> [2015-10-12T20:08:20]
> Bike-shedding:
>
> when:def {...} # !defined $_
> when:num (3) {...} # $_ == 3
> when:str ("foo") {...} # $_ eq "foo"
> when:pat (/bar/) {...} # /bar/
compare:
when (num(3)) { ... }
when (str("foo")) { ... }
This gets you the same behavior, but leaves the test value as a thing that can
be used as the rhs of a match, which means it can be passed around as a first
class predicate value.
The downside is that given a currently possible implementation of &num, it
would do a lot more work than being compiled down to an == operation in the op
tree.
On the other hand, a future &num could provide a faster magic value that ~~'s
implementation can know to directly resolve to a numeric comparison. I'd doubt
it would ever match custom when:num syntax in speed, but I think it is much
more generically useful because it enables tests to be arguments rather than
only in-place parts of the program source.
--
rjbs
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