I am having problem in entering multi-line commands in ghci.
The following 2-line code works from a file:
addTwo :: Int -> Int -> Int
addTwo x y = x + y
But when I enter in ghci, I get an error:
<interactive>:1:1: error:
Variable not in scope: addTwo :: Int -> Int -> Int
I also tried putting the code inside :{ ... :}
, but they are also not working for this example, because this is just appending the lines into one line, which should not be the case.
I am using WinGHCi, version 2011.2.0.1
Most of the time, you can rely on type inference to work out a signature for you. In your example, the following is sufficient:
If you really want a definition with a type signature, or your definition spans over multiple lines, you can do this in ghci:
Note that you can also squeeze this onto one line:
You can find out more about interacting with ghci on the Interactive evaluation at the prompt section of the documentation.