FWIW, the constructs with the initial biggest win for us (in converting procedural thinking) were pattern matching and option types. For pattern matching, the guidelines were
- Don't do any processing after the pattern match within a function; break into smaller functions
- Reach for pattern matching before if/else
- Avoid the use of var
- Avoid dropping through to wildcard pattern. (This tip was from Yaron Minsky of OCaml fame)
In conjunction with preferring the use of combinators over loops, and using Option (and being forced to think about None), we got surprisingly functional Scala code in a short time.
