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copied!<p>Assuming you want the process signature not to change...</p> <pre><code>// continuing from the ops psuedocode def process(data: Seq[Int], b1:Boolean, b2:Boolean, b3:Boolean): Seq[Int] = { @tailrec def loop (acc: Seq[Int], ops: List[Seq[Int] => Seq[Int]]): Seq[Int] = { ops match { case List () => acc case head :: tail => loop (head(acc), tail) } } loop (data, List(( b1,op1 _), (b2,op2 _),(b3,op3 _)).filter{ _._1 }.map{ _._2 }) } </code></pre> <p>The solution is to pair the op with the correct Boolean, in a List, filter out the pairs with untrue Booleans, map the filtered pairs to a list of ops (basically dropping the boolean part of each surviving pair), Then accumulate your transformations recursively over your input data.</p> <p>Here's what it results with some simple operators: import scala.annotations.tailrec</p> <pre><code>def op1(s: Seq[Int]) = s map {_ + 1} def op2(s: Seq[Int]) = s map {_ * 2} def op3(s: Seq[Int]) = s map {_ - 5} def process(data: Seq[Int], b1:Boolean, b2:Boolean, b3:Boolean): Seq[Int] = { @tailrec def loop (acc: Seq[Int], ops: List[Seq[Int] => Seq[Int]]): Seq[Int] = { ops match { case List () => acc case head :: tail => loop (head(acc), tail) } } loop (data, List(( b1,op1 _), (b2,op2 _),(b3,op3 _)).filter{ _._1 }.map{ _._2 }) } process(Seq(1,2,3), true, false, true) // Seq[Int] = List(-3, -2, -1) process(Seq(1,2,3), true, false, false) // Seq[Int] = List(2, 3, 4) process(Seq(1,2,3), false, true, false) // Seq[Int] = List(2, 4, 6) </code></pre>

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