dataclass.edh

# similar to Python's PEP 557 -- Edh has Data Classes too
# https://www.python.org/dev/peps/pep-0557


# %%
# written as a data class
data D ( x, y= nan, ) {
  method __init__(*** _ ) {
    this.total = this.x + this.y
  }
}


# %%
# it satisfies
d = D( 3, 11 )
assert$ d < D( 3, 17 )
assert$ d == D( 3, 11 )
assert$ d is not D( 3, 11 )
d | show


# %%
# equivalent written as a normal class

class D {
  method __init__(
    x as this.x,
    y as this.y= nan,
  ) {
    this.total = this.x + this.y
  }

  method __repr__() {
    return 'D( ' ++ this.x ++ ', ' ++ this.y ++ ", )"
  }
  __str__ = __repr__

  method __eq__( other ) case other of {
    { { D:d' } } -> {
      ; | this.x != d'.x -> false
      ; | this.y != d'.y -> false
      true
    }
    _ -> false
  }

  method __compare__( other ) case other of {
    { { D:d' } } -> {
      case compare( this.x, d'.x ) of {
        EQ -> pass
        { [ LT, GT ] } -> { conclusion } -> return conclusion
        _ -> return NA
      }
      case compare( this.y, d'.y ) of {
        EQ -> pass
        { [ LT, GT ] } -> { conclusion } -> return conclusion
        _ -> return NA
      }
      EQ
    }
    _ -> NA
  }
}