tutorial.law

ob Base Point = { x: Float, y: Float }

ob Base Bool = [ true: {}, false: {} ]

ar not : Bool --> Bool =
  [ true  = {} false.,
    false = {} true. ]

ob Base ListF =
  [ empty: {},
    cons:  { head: Float, tail: ListF }
  ]

ob Base ListPoint =
  [ empty: {},
    cons:  { head: Point, tail: ListPoint }
  ]

ar zip : { xs: ListF, ys: ListF } --> ListPoint =
  @xs [ empty = {} empty.,
        cons  = @ys [ empty = {} empty.,
                      cons  = { head = { x = .xs .head,
                                         y = .ys .head },
                                tail = { xs = .xs .tail,
                                         ys = .ys .tail } zip
                              } cons. ] ]

ar ex : {} --> ListF =
  empty.
  { head = 0.0,   tail = } cons.
  { head = 1.2,   tail = } cons.
  { head = 100.0, tail = } cons.

ar main : {} --> ListPoint =
  { xs = ex, ys = ex } zip