fooling around with sbt settings

does not properly implement equals.scala

import sbt._
import Keys._

object Blah extends Build {
  val mySettings = Project.defaultSettings ++ Seq[Setting[_]](
    crossScalaVersions := Seq("2.9.2", "2.10.4")
  )

  val moreSettings: Seq[Setting[_]] = (mySettings filter { setting: Setting[_] =>
    setting != (crossScalaVersions := Seq("2.9.2", "2.10.4"))
  })

  lazy val one = Project(
    id = "one",
    base = file("."),
    settings = mySettings
  )

  lazy val two = Project(
    id = "two",
    base = file("./src"),
    settings = moreSettings
  )
}

~= operator to the rescue.scala

import sbt._
import Keys._

object Blah extends Build {
  val mySettings = Project.defaultSettings ++ Seq[Setting[_]](
    crossScalaVersions := Seq("2.9.2", "2.10.4")
  )

  val moreSettings: Seq[Setting[_]] = mySettings :+
    (crossScalaVersions ~= { seq => seq.filter(_ != "2.9.2") })

  lazy val one = Project(
    id = "one",
    base = file("."),
    settings = mySettings
  )

  lazy val two = Project(
    id = "two",
    base = file("./src"),
    settings = moreSettings
  )
}