import Prelude ([](..))

[Simon Peyton-Jones]

Lists are regarded by Haskell 98 as "syntax", so you don't import or hide them.  The type [], the constructors [] and : are all not importable or hidable, any more than 'case' is.  So you can define your own prelude, but you can't redefine what list syntax means.

Simon

| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org [mailto:glasgow-haskell-users-
| bounces at haskell.org] On Behalf Of Martin Sjögren
| Sent: 07 November 2003 10:15
| To: glasgow-haskell-users at haskell.org
| Subject: import Prelude ([](..))
| 
| Hello ghc users!
| 
| In my experiments with analyzing Haskell programs, I frequently use my
| own Prelude variants but want to import parts of the real Prelude for
| simplicity.
| 
| In ghc 5, I could write:
|   import Prelude ([](..))
| and then use lists as usual. In ghc 6, though, I get:
|   "parse error on input `['"
| 
| Is there a secret way to import the list type that I don't know of? Is
| ghc 5 or ghc 6 wrong? :)
| 
| Using the "hiding" is not really an option, since I normally want just
| one or two types from the Prelude and then provide other things myself.
| 
| 
| Regards,
| Martin
| --
| Martin Sjögren
|   sjogren at debian.org -- marvin at dum.chalmers.se
|   GPG key: http://www.mdstud.chalmers.se/~md9ms/gpg.html
|   let hello = "hello" : hello in putStr (unlines hello)