[Haskell-cafe] emacs haskell-mode indentation

[Jeremy Shaw]

At Tue, 1 Jun 2004 19:04:56 -0400,
Nathan Weston wrote:
> 
> I am learning haskell from "The Haskell School of Expression", and finding the 
> indentation in the emacs mode rather unhelpful. When I try to type in the 
> following example from the book:
> 
> main = runGraphics (
>        do w <- openWindow "Graphics" (300,300)
>           drawInWindow w (text(100,200) "Hello, world!")
>           k <- getKey w
>           closeWindow w       
> 		   )
> 
> emacs wants to indent it like so:
> 
> main = runGraphics (
>        do w <- openWindow "Graphics" (300,300)
>        drawInWindow w (text(100,200) "Hello, world!")
>        k <- getKey w
>        closeWindow w       
> 		   )
> 
> (For those not using a fixed-width font, in the first example, everything 
> lines up under the 'w <-', in the second, everything lines up under the 'do')
> 
> If I let emacs have its way, I get a syntax error.
> Am I doing something wrong here? Is the emacs mode broken?

The emacs mode definately leaves much to be desired, you could try
formatting the code like this instead:

main = runGraphics $
       do w <- openWindow "Graphics" (300,300)
	  drawInWindow w (text(100,200) "Hello, world!")
	  k <- getKey w
	  closeWindow w

The type signature for $ is:

($) :: forall b a. (a -> b) -> a -> b

I think the ($) operator was invented entirely for rewriting
expressions without parens...

Jeremy Shaw.
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