At 11:32 AM 01-24-2002 -0500, Dan Sugalski wrote: >At 4:19 PM +0000 1/24/02, Dave Mitchell wrote: >>Dan Sugalski <[EMAIL PROTECTED]> wrote: >>> That was my biggest objection. I like the thought of having a scheme >>> pair data type. The interpreter should see it, and it should be >>> accessed, as a restricted array, one with only two entries. >> >>Is this then the same datatype as a Perl6 pair (cf '=>' op in Apo 3) ?? > >Good point. it probably is, yes. (Though there may be potential >differences--depends on whether the scheme pair can only have scalars on >each side, or should allow other things)
In scheme, at least, pairs can contain any data on either side. The notation for a pair is (value . value), and standard list notation (a b c d e f g) is simply syntactic sugar for (a . (b . (c . (d . (e . (f . (g . '()))))))). Although only the cdr of these pairs contain pairs, in a list like ((a a) (b b)) (also written as "((a . (a . '())) . ((b . (b . '())) . '()))"), both the car and cdr of the outermost pair contain pairs.
