Thanks for the input. I tried with Lazy Racket in the language menu instead of #lang, but it does not really do what I want (ie. Haskell). Actually, apart from the fact that things are printed differently, the result is quite the same:
> ones (cons 1 (delay ...)) ;; ! is not enough > (! ones) (cons 1 (delay ...)) > (!! ones) (shared ((-0- (cons 1 -0-))) -0-) -- Éric On Nov 14, 2011, at 6:12 PM, Stephen Chang wrote: > The problem is that only applications are wrapped with the > toplevel-forcer. (And you don't actually need !!. Just the regular ! > should be sufficient.) > > For a short term solution, if you select Lazy Racket in the language > menu instead of #lang lazy, it will do what you want, due to a > subtlety in the way languages are implemented. Lazy Racket when > selected in the menu is implemented as a "tool", so top level > variables are wrapped with #%top, which gets forced. #lang languages > are module languages and module level variables have no such wrapping. > > ps racket-dev, should the #%top from lazy racket be removed? > > > > > On Mon, Nov 14, 2011 at 2:53 PM, Eric Tanter <etan...@dcc.uchile.cl> wrote: >> Hi, >> >> I'd like to tweak Lazy Racket such that the top-level interactions in the >> REPL always use `!!' (recursive force), in order to mimic Haskell's behavior >> as close as possible. >> >> If someone can help me in the very brief term, I would really appreciate it >> (I plan to start teaching on laziness using Lazy Racket tomorrow). >> >> Thanks in advance! >> >> -- Éric >> >> PS: Eli told me of some parameter that controls this behavior. I think it is >> `toplevel-forcer', but a) I'm not sure, b) even if I hack it manually (edit >> lazy.rkt), it does not work: >> >> ;; parameter is properly set to `!!' >>> (toplevel-forcer) >> #<procedure:!!> >> >>> ones >> #<promise:ones> >> >>> (!! ones) >> #0='(1 . #0#) >> >> I'd like the following behavior: >>> ones >> #0='(1 . #0#) >> _________________________________________________ >> For list-related administrative tasks: >> http://lists.racket-lang.org/listinfo/users >> > _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
