How does the first form work out as an inline function argument? I'm not familiar with Haskell's syntax.

I think I misunderstood you before. I thought you were talking about putting multiple statements on a line.

But Haskell can pass around code blocks as well, with or without significant whitespace.

For example, I can define a function called 'forever' to run a sequence of actions forever like so:

  forever x = x >> forever x

Where 'x' is any sequence of actions. You can pronounce '>>' as "followed by". (These are monadic actions, actually, but nevermind that.)

I can invoke it like so:

  myFunc = forever (do {this; that; other})

or:

  myFunc = forever $ do
    this
    that
    other

The dollar sign is a function that lets you dispense with some parentheses. Think of it like an opening paren that closes at the end of the subexpression it's in.

If the block is a function rather than a sequence of actions, Haskell uses '\' as a lambda for introducing anonymous functions.

For example, the function 'map' takes a unary function and calls it with each value from a list. Below I'll call it with an anonymous function which returns double its argument:

  map (\x -> x * 2) [1,2,3]

This results in a new list [2,4,6].

Another good example:

    forM_ [1..9] $ \i -> do
      this i
      that
      other