atomo-0.4: prelude/comparable.atomo

a matches?: b := a == b

a <=> b :=
  condition: {
    a > b -> 1
    a < b -> -1
    otherwise -> 0
  }

x max: y :=
  if: (x > y) then: { x } else: { y }

x min: y :=
  if: (x < y) then: { x } else: { y }

for-macro regexp?: e :=
  e type match: {
    @primitive ->
      (evaluate: e) is-a?: Regexp

    @macro-quote ->
      e name == "r"

    _ -> False
  }

macro (x case-of: (bs: Block))
  { chain = bs contents reduce-right:
      { `(~test -> ~branch) x |
        condition: {
          regexp?: test ->
            `((~test match: !v) match: {
                @none -> ~x
                @(ok: !b) -> !b bindings join: { ~branch }
              })

          test == '_ -> branch

          otherwise ->
            `(if: (~test matches?: !v) then: { ~branch } else: { ~x })
        }
      } with: '@ok

    `({ !v | ~chain } call: ~x)
  } call