On Sat, Feb 04, 2006 at 02:52:20PM -0000, Brian Hulley wrote:
Hi - In the Haskell98 report section 4.4.2 $ is specified as being right associative. This means that f $ a0 a1 $ b0 b1 would parse as f (a0 a1 (b0 b1)) which seems rather strange to me. Surely it would be much more useful if $ were defined as left associative so that it could be used to separate the args to f?
Does anyone know why this strange associativity was chosen?
Probably it was anticipated that right associative version will be more useful. You can use it to create a chain of transformations, similar to a chain of composed functions: (f . g . h) x = f $ g $ h $ x Example: map f $ group $ sort $ filter g $ l But of course, left associative version can also be useful. Some time ago I used a left associative version of the strict application operator, which I named (!$). Anyway, you can't always remove all parentheses. And why would you want to? Everybody is used to them. Best regards Tomasz -- I am searching for programmers who are good at least in (Haskell || ML) && (Linux || FreeBSD || math) for work in Warsaw, Poland