This tool lets you interact with values and functions directly.
Install Elm Platform to get elm-repl
. Then make sure you have
node.js installed because it is needed to
evaluate the generated JS.
You can type in expressions, definitions, ADTs, and module imports using normal Elm syntax.
> 1 + 1
2 : number
> "hello" ++ "world"
"helloworld" : String
The same can be done with definitions and ADTs:
> fortyTwo = 42
42 : number
> f n = n + 1
<function> : number -> number
> f 41
42 : number
> factorial n = \
| if n < 1 then 1 \
| else n * factorial (n-1)
<function> : number -> number
> factorial 5
120 : number
> type Either a b = Left a | Right b
> case Left 32 of \
| Left n -> 2 * n \
| Right m -> m + 1
64 : number
You can import standard libraries and any library
reachable from the directory where elm-repl
is running:
> import String
> String.length "hello"
5 : Int
> String.reverse "flow"
"wolf" : String