[ikarus-users] junctive macro

[Eduardo Cavazos]

Hello,

Here's another approach to the "junctive comparisons". A junctive macro:

(define-syntax junctive

  (syntax-rules ()

    ( (junctive compare (f args-1) (g args-2))

      (f (lambda (a)
           (g (lambda (b)
                (compare a b))
              args-2))
         args-1) )

    ( (junctive compare arg (g args-2))

      (junctive compare (any (list arg)) (g args-2)) )

    ( (junctive compare (f args-1) arg)

      (junctive compare (f args-1) (any (list arg))) )))

It's simpler than it looks. Only the first clause is essential, the
last two are for the special cases of a single element.

Couple of examples from the note on the Perl 6 list:

    $dice_sum == 7 | 11

would be:

    (junctive = dice-sum (any '(7 11)))

any(@new_values) > all(@existing_values)

    (junctive > (any new-values) (every existing-values))

Ed