Re: [Haskell-cafe] Pattern matching does not work like this?

On Jul 15, 2009, at 9:59 PM, minh thu wrote:

2009/7/15 Magicloud Magiclouds :

...

Hi, I do not notice this before. "fun ([0, 1] ++ xs) = .." in my code could not be compiled, parse error.

++ is a function; you can't pattern-match on that.

Doesn't matter, it's not trying to. Part of Erlang syntax is that in a pattern [c1,...,cn] ++ P is equivalent to [c1,...,cn|P] For example, wee(X) -> F = fun ([0,1] ++ L) -> L end, F(X). is perfectly legal. The problem might be the "xs", or it might be the "=". Presumably it should be fun ([0,1] ++ Xs) -> ...