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re: Something I've come to appreciate about dynamic typing VIEW POST

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re: This case can be a Map.
 

Maps in statically typed languages require all the values to be the same type, though, unlike structs.

 

That's only a problem if a language doesn't have sum types. If we use OCaml again, with the person_info discriminated union above, it's easy to make a map with different types:

type person_info = Name of string | Age of int
module Person = Map.Make(String)
let p = 
  Person.empty 
  |> Person.add "name" (Name "Baby Yoda") 
  |> Person.add "age" (Age 50)
Person.find "name" p
- : person_info = Name "Baby Yoda"
Person.find "age" p
- : person_info = Age 50

Ooh. I don't know OCaml, but that looks interesting. I guess I could probably implement something similar in Haskell.

Exactly the same principle in Haskell:

import qualified Data.Map.Strict as Map

data PersonInfo = Name String | Age Integer

m = Map.fromList [("name", Name "Baby Yoda"), ("age", Age 50)]
Map.lookup "name" m
Just (Name name) = Map.lookup "name" m
name
-- => "Baby Yoda"
 

Some static languages have reflections and libraries for dynamism where you need them.

Scala have dynamic trait.
Haxe have dynamic types.
Java have reflection and libs to help.
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