Dominic J Steinitz Dominic.J.Steinitz@BritishAirways.com writes:

Can anyone tell me why this behaves as it does? In Hugs, I get

C:\My Documents\functional\ldapsck1\buffer.hs Main> main

Illegal operation (561 reductions, 1029 cells)

..program elided...

The reason for the behaviour you're seeing is that Hugs doesn't report you reading past the end of the file as an EOF error (Hugs never reports EOF errors, but maps them to illegal ops instead). So, to have it work with both Hugs and GHC, you need to change the 'Left' branch of the case expression in 'main' from Left e -> if isEOFError e then do .... else do ... to Left e -> if isEOFError e || isIllegalOperation e then do .... else do ... hth --sigbjorn