On Thu, Feb 17, 2005 at 02:18:55AM -0600, Rod Adams wrote:
: The simple if is:
:
: if $x ~~ (1,2,3,4) {...} # parens needed here since , is lower than ~~
: in precedence.
That is asking if $x is a list containing 1,2,3,4.
: Same for unless/while/until. And all of this from the entirely useful C<
: ~~ >. The S04 code describing @Array ~~ $Scalar (for Num/Str) uses
: junctions, but I'd argue a better implementation would be a short
: circuiting C< for > loop, even if junctions exist. It's just plain
: faster that way.
Junctions can short circuit when they feel like it, and might in some
cases do a better job of picking the evaluation order than a human.
: So what I see now for utility of junctions is thus:
:
: - Common cases which C< ~~ > appears to handle for us suitably well.
Only if we make lists second-class citizens. The need for junctions
first became evident when we found ourselves filling the ~~ tables
with various sorts of weird non-symmetries.
: - Edge cases which, IMHO, do not merit the huffman level of several
: single character operators. All of which can be accomplished without the
: use of junctions, though not as gracefully.
Grace is important. Even more important is mapping naturally to human
linguistic structures, to the extent that it can be done unambiguously.
: I see no need for junctions in core.
I do, and I'm not likely to change my mind on this one. Sorry.
Larry
