Hello Ross, Monday, February 06, 2006, 2:35:40 PM, you wrote: RP> A patch implementing a relaxed termination constraint is at RP> http://www.soi.city.ac.uk/~ross/instance-termination.patch [this patch provides the following:] RP> With -fglasgow-exts but not -fallow-undecidable-instances RP> (1) no variable has more occurrences in the assertion than in the RP> head, and RP> (2) the assertion has fewer constructors and variables (taken together RP> and counting repetitions) than the head. i always thinks that existing rules too restrictive and something like just counting chars at the left and right should be used ;) one question - will be the same rules incorporated in Hugs? as you know, i'm trying to made Hugs+GHC compatible library, so this matters it will be even better if such improvement could be made to other Haskell compilers and included in Haskell-prime standard. class system of H98 and existing compilers is especially restricting flight of my imagination :) -- Best regards, Bulat mailto:bulatz@HotPOP.com