[Haskell-beginners] having trouble with helloworld style program

[Antoine Latter]

On Mon, Aug 8, 2011 at 11:08 AM, David Place <d at vidplace.com> wrote:
>
> main =do
>
>   x<-getLine
>
>   y<-return x
>
>   print $ stringToInt y
>
> This is exactly equivalent to the other methods, but has the additional
> 'return', which is a no-op.  Please do not suggest such a style.
>
>
> Really?  Without the return it will not work. So, it isn't a noop.
> Stylistically, I like it better than the 'let' in 'do' notation.

I think he means that the entire line is a no-op.

The line:

> y <- return x

is equivalent to:

> let y = x

and since re-naming a value doesn't perform any computation, you may
as well delete the line and use 'x' everywhere you would have used
'y':

> main =do
>   x<-getLine
>   print $ stringToInt x


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