Scala type-safety vs overhead (type vs class) -


i have graph, each vertex has both id (which never changes) , label (which changes frequently). both represented longs.

currently, define following types:

type vertexid = long type vertexlabel = long

however, discovered bug today passing in vertexlabel function expected vertexid. seems type of thing scala compiler should able prevent.

i considered doing instead:

case class vertexid(id: long) case class vertexlabel(label: long)

but there's overhead of "boxing" , "unboxing" , memory usage.

is there anyway best of both worlds? define both types longs in such way compiler prevent using 1 other?

yes, can use value classes:

case class vertexid(val id: long) extends anyval case class vertexlabel(val label: long) extends anyval

see http://docs.scala-lang.org/overviews/core/value-classes.html


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