Hi John <snip>
Also, I defined this in my source file:
test :: forall a. (Num a) => a test = 2 * 5 + 3
Now, it can be used:
NumTest> test 13 NumTest> rpnShow test "2 5 * 3 +" NumTest> prettyShow test "(2*5)+3" NumTest> test + 5 18 <snip>
I had newer seen anybody use "forall a." in function signatures before, and therefore was curious about its effect. This is probably do to my inexperience regarding Haskell. However, I tried to remove it and wrote this instead: test :: (Num a) => a and the code still compiled and seems to run fine. Also using the prettyShow and rpnShow functions. So, why are you using the forall keyword? (this is not meant as a critique, i am just curious) I tried to find documentation about the use of the forall keyword in respect to functions (I do know about it in with respect to existentially quantified types), but with no luck. So, if anybody has some good pointers, please let med know about it. /Mads Lindstrøm