ternary operator like expression

ternary_like.sml

datatype 'a ternarylikeop = TrueExpression of 'a | FalseExpression

fun op ? (true, y)  = TrueExpression y
  | op ? (_, y)     = FalseExpression
infix 6 ?;

fun op :- (TrueExpression x, _) = x
  | op :- (FalseExpression, y)  = y
infix 6 :-;

val test01 = (35 < 3) ? 2 :- 1;
val test02 = (35 > 3) ? 2 :- 1;

(*
- [opening /Users/smly/gitws/practice/smlnj/ternary_operation.sml]
datatype 'a ternarylikeop = FalseExpression | TrueExpression of 'a
val ? = fn : bool * 'a -> 'a ternarylikeop
infix 6 ?
val :- = fn : 'a ternarylikeop * 'a -> 'a
infix 6 :-
val test01 = 1 : int
val test02 = 2 : int
*)