On 12 Feb 2002, Pixel wrote:
eurk
ERROR "/usr/share/hugs/lib/exts/ST.hs":48 - Syntax error in type expression (unexpected `.')
isn't there a way ST.hs would require the extensions? a pragma or something? someone not knowing the "-98" would wonder for a long time about what to do :-(
That could be nice, at least for ST.hs (in ghc the equivalent of hugs option "-98" isn't needed)
anyway, the simplest examples i found:
show $ runST (do { x <- newSTRef 2; writeSTRef x 3 ; readSTRef x })
so i can write:
newSTRef in "reference (pointer)" "creation" readSTRef writeSTRef in "reference (pointer)" "dereference"
WDYT?
If you understand your explanations for newSTRef etc. that's fine with me. My code in this thread (which coincidentally is a no-op) emphasizes which ones you would use "<-" with. So let me make one final adjustment so that: do{ x<-newSTRef 3; y <-readSTRef x; writeSTRef x (y+4);readSTRef x} Too long?
PS: show $ runST $ do { x <- newSTRef 2; writeSTRef x 3 ; readSTRef x } is not working :'-( _______________________________________________
Does typing in the following work? runST (do { x <- newSTRef 2; writeSTRef x 3 ; readSTRef x }) I can't explain and dont understand the error I get from the compiler with your code. (the haskell compilers I've used are not very helpful in error messages) Btw to get it to work in ghci you'd have to start: 1. ghci -package lang 2. load in some dummy file with 2 lines (so both Prelude and ST functions are available) ...(lines starting below!).... import ST main = print "hi" ....(lines ending)...... 3. type in runST ( ... ) Somebody would have to fill in the details for me about doing stuff in hugs. Jay