Metaoperators — Z, X, R & hyper

Operators that transform other operators — zip, cross, reverse, and hyper.

A metaoperator modifies another operator. Z and X pair up lists, R reverses operands, and the hyper form »OP« applies an operator element-wise across a list. They compose with almost any infix.

Zip — Z and ZOP #

Z interleaves two lists into pairs; gluing an operator on (Z+) combines each pair with that operator instead.

say (1, 2, 3) Z (4, 5, 6);
say (1, 2, 3) Z+ (10, 20, 30);

((1 4) (2 5) (3 6))
(11 22 33)

Cross — X and XOP #

X forms every combination across its lists; XOP applies an operator to each combination.

say (1, 2) X (3, 4);
say (1, 2) X* (3, 4);

((1 3) (1 4) (2 3) (2 4))
(3 4 6 8)

Reverse — ROP #

R swaps an operator's operands: 10 R- 3 means 3 - 10.

say 10 R- 3;

-7

Hyper — »OP« #

The hyper metaoperator applies an operator to every element of a list (pairing up with a second list, or broadcasting a scalar).

say (1, 2, 3) >>+>> 10;
say (-1, 2, -3)>>.abs;

(11 12 13)
(1 2 3)

Notes #

• These stack with the reduction metaoperator: [Z+] reduces with zip-plus, and so on.
• Hyper operations are explicitly parallel-friendly and may run in any order, so the operator should be side-effect-free; the »« "pointing" arrows show which side may be extended to match lengths.
• >>.method hypers a method call across a list — a concise map: @words>>.uc upper-cases each element.