type

gistfile1.txt

;; map function
(define $map : [$A $B] ([(A -> B) {A}] -> {B})
  (lambda [$fn $xs]
    (match xs (list something)
      {[<nil> {}]
       [<cons $x $rs> {(fn x) @(map fn rs)}]})))
       
;; Ord type class
(type $Ordering {<Less> <Equal> <Greater>})

(define $ordering : (Matcher Ordering)
  (algebraic-data-matcher
    {<less> <equal> <greater>}))

(class $Ord $A :: Eq
  {$lt? : ([A A] -> Bool)}
  {[$lte? : ([A A] -> Bool) (lambda [$x $y] (or (lt? x y) (eq? x y)))]
   [$gte? : ([A A] -> Bool) (lt? $2 $1)]
   [$gt? : ([A A] -> Bool) (lte? $2 $1)]
   [$compare : ([A A] -> Ordering)
    (lambda [$m $n]
      (if (lt? m n)
        <Less>
        (if (eq? m n)
          <Equal>
          <Greater>)))]})

(instance Integer Ord {[$lt? lt-integer?]})