Re: Error when ($) is used, but no error without

Brian Hulley wrote:

In contrast, (forall s. ST s a) is not a true existential, since we are here just simulating an existential by making use of the ST constructor to store the info about what 's' was used so that it can be recovered by pattern matching.

Sorry the above paragraph is wrong ;-) (But see my previous post for how to simulate existentials by a data type (to hide the forall) and use them with $ if this is what you wanted to do) Regards, Brian.