[Haskell-cafe] Layout rule (was Re: PrefixMap: code reviewrequest)

[Jared Updike]

Layout only applies when something is less indented than previous
lines, I believe...

e.g.

> do
> c <- getContents "filename"
> putStrLn "blah"

or

>    do
>    x <- getContents "filename"
>    putStrLn "ok"

works fine but

>     do
> c <- blahAction
> putStrLn "blah"

obviously won't work

  Jared.

On 3/2/06, Brian Hulley <brianh at metamilk.com> wrote:
> Brian Hulley wrote:
> [snip]
> > So any solutions welcome :-)
>
> Thank to everyone who replied to my queries about this whole layout issue.
>
> One other thing I've been wanting to ask (not to change! :-)) for a while
> is: how is the following acceptable according to the rules in the Haskell98
> report where "where" is one of the lexemes, which when followed by a line
> more indented than the line the layout-starting-lexeme is on, should start
> an implicit block:
>
>        module M where
>        data T = .....            -- not indented!
>
> According to my understanding of the layout algorithm, the above code would
> have to be written:
>
>        module M where
>               data T = ....
>
> Can anyone shed some light on what the formal rule is that allows the first
> (and very useful) way of laying out code to be ok?
>
> Thanks, Brian.
>
>
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