Range expressions in Elm

Question

Elm supports [1..100], but if I try ['a'..'z'], the compiler gives me a type mismatch (expects a number, gets a Char). Is there any way do make this work?

Answer 1

Just create a range of numbers and map it to chars:

List.map Char.fromCode [97..122]

Edit, or as a function:

charRange : Char -> Char -> List Char
charRange from to =
  List.map Char.fromCode [(Char.toCode from)..(Char.toCode to)]

charRange 'a' 'd' -- ['a','b','c','d'] : List Char

Edit, from elm 0.18 and up, List.range is finally a function:

charRange : Char -> Char -> List Char
charRange from to =
  List.map Char.fromCode <| List.range (Char.toCode from) (Char.toCode to)