ctags

--langdef=scala
--langmap=scala:.scala
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*(private[^]*|protected)?[ \t]*class[ \t]+([a-zA-Z0-9_]+)/\4/c,classes/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*(private[^]*|protected)?[ \t]*object[ \t]+([a-zA-Z0-9_]+)/\4/c,objects/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*(private[^]*|protected)?[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*case class[\t]+([a-zA-Z0-9_]+)/\6/c,case classes/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*(private[^]*|protected)?[ \t]*case object[ \t]+([a-zA-Z0-9_]+)/\4/c,case objects/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy)[ \t]*)*(private[^]*|protected)?[ \t]*trait[ \t]+([a-zA-Z0-9_]+)/\4/t,traits/
--regex-scala=/^[ \t]*type[ \t]+([a-zA-Z0-9_]+)/\1/T,types/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy|private[^]*(\[[a-z]*\])*|protected)[ \t]*)*def[ \t]+([a-zA-Z0-9_]+)/\4/m,methods/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy|private[^]*|protected)[ \t]*)*val[ \t]+([a-zA-Z0-9_]+)/\3/l,constants/
--regex-scala=/^[ \t]*((abstract|final|sealed|implicit|lazy|private[^]*|protected)[ \t]*)*var[ \t]+([a-zA-Z0-9_]+)/\3/l,variables/
--regex-scala=/^[ \t]*package[ \t]+([a-zA-Z0-9_.]+)/\1/p,packages/