Ha!, What you've done is redefine the (+) function.. try 10 + 30 and see what you get. Your local definition shadows the "real" (+) function defined in the prelude. let a + b = 3 is equivalent to let (+) a b = 3 ... Jinwoo Lee wrote:

Hi,

I'm a Haskell newbie.

I was trying several things with GHCi and found out that the expression "let a + b = 3" does not generate any errors.

Prelude> let a + b = 3 Prelude> a

<interactive>:1: Variable not in scope: `a' Prelude> b

<interactive>:1: Variable not in scope: `b' Prelude>

What does "let a + b = 3" mean in this case?

I also tries with GHC compiler using the code below, but it generates no error.

main :: IO () main = do let a + b = 3 putStrLn "Hello"

Could somebody answer this?

Jinwoo

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Jinwoo Lee wrote:

Hi,

I'm a Haskell newbie.

I was trying several things with GHCi and found out that the expression "let a + b = 3" does not generate any errors.

Prelude> let a + b = 3

Try this: Prelude> let a + b = 3 Prelude> 5+11 3 Your `let a+b=3' has redefined `+' to be a function always evaluating to 3. `a' and `b' are formal parameters of the newly defined function. Martin