On 12/18/05, Daniel Carrera
Hello all,
I'm trying to write the simplest possible Haskell program, and I'm not getting anywhere.
I have installed Hugs, GHC and GHCI. I want to run the following program:
fac :: Integer -> Integer fac 0 = 1 fac n | n > 0 = n * fac (n-1)
This is what I see:
$ hugs Hugs.Base> fac :: Integer -> Integer ERROR - Undefined variable "fac" Hugs.Base> fac 0 = 1 ERROR - Syntax error in input (unexpected `=')
$ ghci Prelude> fac :: Integer -> Integer
<interactive>:1:0: Not in scope: `fac' Prelude> fac 0 = 1 <interactive>:1:6: parse error on input `='
$ # Write the program to fac.hs $ ghc fac.hs
fac.hs:1:0: The main function `main' is not defined in module `Main' When checking the type of the main function `main'
GHC is a compiler. If you want to compile to a binary then you must define a function called 'main'. Otherwise just load the file in ghci (`ghci fac.hs`). -- Friendly, Lemmih