RE: List comprehensions
> Hello, > > Recently, I came accross this > expression: > [ x + y | x <- xs | y <- ys ] > > As far as I can see (Haskell Report), > this is not allowed by the haskell 98 > standard. So I assume it to be an ex- > tension. Where can I find information > about this? This is a parallel list comprehension, a GHC extension. See http://www.haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html#PA RALLEL-LIST-COMPREHENSIONS for more info. The code above does the same as zipWith (+) xs ys, basically. Cheers, Jan ### This message has been scanned by F-Secure Anti-Virus for Microsoft Exchange. For more information, connect to http://www.F-Secure.com/ ### ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: hashmap withdrawal and poor haskell style
> On Wed, 3 Apr 2002, D. Tweed wrote: > > > > main = do content <- getContents > > > let rpt letter = report content letter > > > loop rpt alphabet > > > I'm a bit confused how this can have worked... in Haskell `let' is used in > > the context of a `let ..<1>.. in ..<2>..' where the code ellided in <1> > > binds some names to values which are then used in the expression <2> (as > > in `let x=sqrt 2 in exp x') and so the contents of main isn't (unless I'm > > missing something) syntactically Haskell. > > Beats me, but it was the only (or at least the first) way I > could find to create a function inside a do block... You don't need to create a function, you could use partial parametrization instead: | main = |do content <- getContents | loop (report content) alphabet [snip] HTH, Jan de Wit ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: newtype/datatype (was efficiency)
Hi, > data T -- has 1 value: _|_ Minor nitpick: that Hugs and GHCi accept it, doesn't mean it's legal Haskell'98. Otherwise we would have existential and universal quantified types as well :-) Cheers, Jan ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
