How to write List literals (Or: Differences between Arrays and Lists)

Sorry, (still) newbie here: How can I write List literals?

I know how to write Array literals:


But if I use that with Data.List.length I get the error “Could not match type List with type Array”. This makes sense, but how can I write Lists in my code?

If this is not possible, I might ask: Why is Array the basic data structure (with literals) and List not?

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There’s no literal syntax for List, you must use the operators provided: [3,8,17] translates to 3 : 8 : 17 : Nil. Arrays were chosen for the syntax as JavaScript has a built-in type for arrays, and has the same syntax.


There’s also Data.List - purescript-lists - Pursuit, to which you can pass an array (or any data type which has an instance of the Foldable type class), like so:

import Data.List as List

x = List.fromFoldable [3, 8, 17]

Ah, that’s cool. thanks!