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, union types, and module imports using normal Elm syntax.
> 1 + 1
2 : number
> "hello" ++ "world"
"helloworld" : String
The same can be done with definitions and union types:
> 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
You can import your modules too, so if you create a module named MyThing
in
your project, you can say import MyThing
in the REPL and get access to all the
values it exposes.