On Tue, 29 Oct 2002, David Whipp wrote:
: Larry Wall [mailto:larry@;wall.org] wrote:
: > : unary (postfix) operators:
: > : ... - [maybe] same as ..Inf [Damian votes Yes]
: >
: > I wonder if we can possibly get the Rubyesque leaving out of
: > endpoints by saying something like 1..!10.
:
: Perhaps we could use the less-than symbol: 1 ..< 10
:
: Similarly: 1 >..< 10 == 2..9
That front one is backwards--it would have to be 1 <..< 10.
But the biggest problem is that 1..<$iterator> is valid syntax.
Of course, ..! and ..^ have the same problem. But it just seems like
it's really unlikely that someone would use a unary ! or ^ on the
endpoint term. So with 1..!$x or 1..^$x it's likely to be right if
we guess (per the longest token rule) that the operator is ..! or ..^.
The same can't be said of ..<, alas. But at least it might produce
a syntax error when it tries to parse the >. Or no, it wouldn't
necessarily. This parses:
1..<$iterator> + 1;
but wrongly as
1 ..< $iterator > +1;
Ick.
Of course, Real Mathematicians will want [1..10) and (1..10] instead.
Double ick.
I kind like ..^ the best because ^ is currently read "exclusive of"
anyway, sort of...
And the arrow can be read "up to", at least on that end of it. I think
that ..^ is going to be much, much more common than ^.. will be.
There's also an issue of what (1..10) - 1 would or should mean, if anything.
Does it mean (1..9)? Does 1 + (1..10) mean (2..10)?
And what would ('a' .. 'z') - 1 mean?
I think I'd better go to bed now...
Larry
