Re:Just-In-Time Static Type Checking for Dynamic Languages
by ubertaco on Tuesday April 19, 2016 @05:11PM
(#11530461)
Alternatively, in MLs (this sample specifically is OCaml) :
type expression =
| Number of float
| Add of expression * expression
| Subtract of expression * expression
| Multiply of expression * expression
| Divide of expression * expression
let rec eval expr =
match expr with
| Number n -> n
| Add (expr1, expr2) -> (eval expr1) +. (eval expr2)
| Subtract (expr1, expr2) -> (eval expr1) -. (eval expr2)
| Multiply (expr1, expr2) -> (eval expr1) *. (eval expr2)
| Divide (expr1, expr2) -> (eval expr1) /. (eval expr2)
Hey look, I just built a calculator DSL. And everything is statically typed and typechecked (and if I left off the "Divide" case in my "eval" method, it would warn me).
Is objectively less readable than
def marketDataService = new Factory<MarketDataService<Stock>>()
And even the latter is not the best.
def MyClass(marketDataService){
}It's imho the most readable. If the name is self describing and there are unit tests that prove that I'm receiving the correct type I cannot care less about the type itself.