small extension to `...` notation

In Haskell we write `f` in order to infixify the identifier f. In ABC the stuff between backquotes is not limited to an identifier, but any expression may occur there. This would allow one to write e.g. xs `zipWith (+)` ys In general <expr1> `<expr2>` <expr3> => (<expr2>) <expr1> <expr3> I think it is a small extension to Haskell, which does not break anything existing, and provides yet another opportunity to beautify one programs, especially in combination with programs like lhs2TeX. Doaitse Swierstra