scalaVersion := "2.12.3"
name := "hbt"
organization := "com.lihaoyi"
libraryDependencies += "com.lihaoyi" %% "sourcecode" % "0.1.4"
sourceGenerators in Compile += Def.task {
val dir = (sourceManaged in Compile).value
val file = dir/"fasterparser"/"SequencerGen.scala"
// Only go up to 21, because adding the last element makes it 22
val tuples = (2 to 21).map{ i =>
val ts = (1 to i) map ("T" + _)
val chunks = (1 to i) map { n =>
s"t._$n"
}
val tsD = (ts :+ "D").mkString(",")
s"""
implicit def Sequencer$i[$tsD]: Sequencer[(${ts.mkString(", ")}), D, ($tsD)] =
Sequencer0((t, d) => (${chunks.mkString(", ")}, d))
"""
}
val output = s"""
package hbt
trait SequencerGen[Sequencer[_, _, _]] extends LowestPriSequencer[Sequencer]{
protected[this] def Sequencer0[A, B, C](f: (A, B) => C): Sequencer[A, B, C]
${tuples.mkString("\n")}
}
trait LowestPriSequencer[Sequencer[_, _, _]]{
protected[this] def Sequencer0[A, B, C](f: (A, B) => C): Sequencer[A, B, C]
implicit def Sequencer1[T1, T2]: Sequencer[T1, T2, (T1, T2)] = Sequencer0{case (t1, t2) => (t1, t2)}
}
""".stripMargin
IO.write(file, output)
Seq(file)
}