the dreaded offside rule

[Malcolm Wallace]

"Simon Marlow" <simonmar at microsoft.com> wrote:

> Here's another couple that just occurred to me:
> 
>   f x | let y = x = y
>   f x = case x of _ | let y = x -> y
> 
> granted these are unlikely to occur in practice.

Are these Haskell'98?  I'm afraid I don't understand how a let binding
(without "in") can occur in a guard for a function decl or case branch.
In Ben's examples, the vertical bar was not a guard, but the separator
in a comprehension (although he omitted to show the surrounding
brackets...)

    [ ... | let x, y :: T
              x = 3
              y = 4,
            ... ]

    [ ... | let x = 3, ... ]

Regards,
  Malcolm