[dwc]

Erlang's pattern matching allows a great many things to be done in a declarative style. For some problems you end up with a lot of pattern stuff and not all that much "normal" code. Or you pattern match through what would ordinarily be a lot of flow control statements, for each case writing very simple code to handle that one thing.

Since Erlang isn't a declarative language in the larger sense, that's my guess what he meant.