Short Levenshtein distance implementation in Scala

EditDistance.scala

package net.tixxit.levenshtein

import scala.math.min

object EditDistance {
  def editDist[A](a: Iterable[A], b: Iterable[A]) =
    ((0 to b.size).toList /: a)((prev, x) =>
      (prev zip prev.tail zip b).scanLeft(prev.head + 1) {
          case (h, ((d, v), y)) => min(min(h + 1, v + 1), d + (if (x == y) 0 else 1))
        }) last
}

This is a super awesome implementation and it works really well. I'm having a hard time figuring out what this line does:

(0 to b.size).toList /: a)((prev, x)

Specifically, I can't find anything when searching that describes the /: operator. Think you could lend some help?

@jasonleehodges http://www.scala-lang.org/api/2.12.3/scala/collection/Seq.html#/:[B](z:B)(op:(B,A)=>B):B

I'm not saying I know a lot about it BUT I am also looking it up and found this

edit: its just a fancy syntax for foldLeft.

/: is foldLeft

Could you please give an example of usage please?