[Haskell-cafe] buildExpressionParser prefix recursion

[Warren Harris]

I was wondering why Parsec's buildExpressionParser doesn't allow  
prefix expressions to be handled recursively, e.g. given a prefix "!"  
operation, it seems that "!!a" could parse without requiring  
parentheses ("!(!a)"). Is there an easy way to extend it? (I have a  
rich expression grammar I'd like to parse which includes several  
prefix forms, and it would be a shame to have to abandon  
buildExpressionParser since it is so concise and convenient.) Thanks,

Warren