I came really late to this discussion, so I assume someone has already proposed using (Control.Applicative.<|>) to select the first matching pattern of an unnamed cased object. Can someone point me to where that was proposed and why it was rejected? Dan Weston Isaac Dupree wrote:
Duncan Coutts wrote:
On Wed, 2007-08-15 at 18:23 +0100, Brian Hulley wrote:
Therefore I propose:
\of alts
which doesn't suffer this problem since the keyword "of" can never follow a '\' in the existing grammar.
Or how about:
\case of alts
which seems clearer to me.
Similarly, the keyword "case" can never follow a '\' in the existing grammar.
Mind you, this doesn't seem to save much over
\x -> case x of alts
It saves the writer using an explicit name which must be unique and the reader determining that the name is not used deeper in the expressions. (and a "->"). I tend to find myself wanting this after already having written a 'case' and decided I don't need/want a name for the thing being 'cased'. I wouldn't mind "case of", "\of" or "\case of", for using it.
Allowing multiple arguments - is syntactically difficult to reconcile with 'case' because it restricts what single-argument forms can be used? Such as:
case foo of Just n -> n is allowed but f Just n = n isn't.
Isaac _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe