+.y yields a two-element list of the real and imaginary parts of
its argument. For example, +.3j5 is 3 5,
and +.3 is 3 0 .
x+.y is the greatest common divisor of x
and y .If the arguments are boolean (0 or 1),
the functions +. and *. are equivalent to logical or
and and. The function-.similarly restricted
is not.
The greatest common divisor divides both of its
arguments x and y to produce results that have
no common factor, that is, the GCD of the quotients is 1.
Moreover, these quotients represent the fraction x%y in lowest form.
For example:
Since the functions =| and =<.
(tests for non-negative and for integer) produce boolean results,
the phrase (=|)+.(=<.) is a test for non-negative or
integer:
(test=: (=|) +. (=<.)) _2 _2.4 3 3.5
1 0 1 1
The duality of or and and may be shown as follows: