lib.compareLists

Compare two lists element-by-element with a comparison function cmp.

List elements are compared pairwise in order by the provided comparison function cmp, the first non-equal pair of elements determines the result.

Inputs

cmp

The comparison function a: b: ... must return:

• 0 if a and b are equal
• 1 if a is greater than b
• -1 if a is less than b

See lib.compare for a an example implementation.

a

The first list

b

The second list

Examples

compareLists lib.compare [] []
=> 0
compareLists lib.compare [] [ "a" ]
=> -1
compareLists lib.compare [ "a" ] []
=> 1
compareLists lib.compare [ "a" "b" ] [ "a" "c" ]
=> -1

Noogle detected

• lib.lists.compareLists

compareLists =
    cmp: a: b:
    if a == [ ] then
      if b == [ ] then 0 else -1
    else if b == [ ] then
      1
    else
      let
        rel = cmp (head a) (head b);
      in
      if rel == 0 then compareLists cmp (tail a) (tail b) else rel;