Thanks a lot for your help I got the idea of this symbol now. It will be great if you can help me this time as well, this time is the symbol @
Here is the code that i got > evalExpr :: Expr -> Mem -> (Bool,Expr) > evalExpr (Val x) _ = (True,Val x) > evalExpr (Var n) env = if isNothing (lookup n env) then > (False,Var n) else (True,Val (envLookup n env)) > evalExpr c@(App op e1 e2) e = let (b1,v1) = (evalExpr e1 e) > (b2,v2) = (evalExpr e2 e) > > > in if b1 && b2 then (True,Val (eval c e)) else (False,App op v1 v2) > Thanks once more Best regard Maverick Stefan Holdermans wrote: > > Maverick, > >> Do you mind tell what is mean by the symbol $ in this piece of >> code? Thanks >> a lot. > > It denotes function application: > > infixr 1 $ > > ($) :: (a -> b) -> a -> b > f $ x = f x > > Note how its precedence and associativity is the opposite of that of > 'regular' function application. The ($) is typically used to limit > the number of parentheses needed in a piece of code: > > f (g (h x)) vs. f $ g $ h $ x > > There are other options though: > > (f . g . h) x > f . g . h $ x > > HTH, > > Stefan > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe > > -- View this message in context: http://www.nabble.com/symbol-%24-tf3701618.html#a10362633 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
