How do I convert a list of chars to a string in purescript

Question

I'm looking for an idiomatic way to write a function List Char -> String in Purescript.

This seems like a simple thing to do, but I'm new to Purescript and have been browsing documentation for a while now with no progress!

Background information: I am porting a simple function from Haskell to Purescript

generateId :: Int -> [Char]

This generates a String of specified length. It was quite easy to convert the code to use List Char operations (where List is from Data.List in Purescript). In Haskell [Char] is the same as String so no other processing is needed, however, I can't find a function to convert from List Char to a native String in Purescript!

~~My search lead me to fromCharArray :: Array Char -> String in Data.String, however I could not find a way to convert from List Char to an Array Char!~~

I could manually convert between them by folding over List Char and building an Array Char using snoc, but surely I must be missing an inbuilt solution for what seems like basic String manipulation in Purescript!

Edit: fromList works to convert from any Unfoldable (such as Arrays) to a List. Still leaving this question open in case there is a more idiomatic way of achieving this.

`Data.String.fromCharArray <<< Data.List.fromList` sounds pretty decent to me. `fromCharArray` is implemented in native JS with `array.join("")`. — stholzm, Jan 02 '16 at 13:45
Yup, I'll take that as the idiomatic way of achieving this. Thanks! — Anupam Jain, Jan 03 '16 at 03:10
@stholzm you should post that as an answer since it resolves the question... — sclv, Mar 19 '16 at 07:07

stholzm · Accepted Answer · 2016-03-26T09:13:24.243

6

I agree with your edit. Data.String.fromCharArray <<< Data.List.fromList sounds pretty decent to me. fromCharArray is implemented in native JS with array.join("").

Update: fromList is deprecated now - use toUnfoldable instead

edited Mar 26 '16 at 09:13

answered Mar 19 '16 at 18:27

stholzm

3,395
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score 2 · Answer 2 · answered Jan 01 '21 at 17:45

[Updated Jan 2021]

In PureScript 0.13.8:

import Prelude 

> import Data.Array (toUnfoldable)
> import Data.String.CodeUnits (fromCharArray)
> fromListChars = fromCharArray <<< toUnfoldable
> fromListChars ['2', '0', '2', '1']
"2021"

> fromListChars []
""

How do I convert a list of chars to a string in purescript

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