This doesn't work, but if it did you could simplify the switch statement to: switch v:= x.(type) { case int32, int64, float32, float64: if v <

This doesn't work, but if it did you could simplify the switch statement to: switch v:= x.(type) { case int32, int64, float32, float64: if v < 0 { return -v } } Go has some neat improvements to the switch statement: http://golang.org/doc/effective_go.html#switch http://golang.org/doc/effective_go.html#switch