The first match through a stream pipeline

#!ek9
defines module site.flowControl.firstmatch

  defines function

    startsWithA() as pure
      -> item as String
      <- rtn as Boolean: item matches /^A.*/

  defines program

    FirstMatch()
      stdout <- Stdout()
      items <- ["Beta", "Alpha", "Avocado"]

      firstMatch <- cat items
        | filter by startsWithA
        | head 1
        | collect as List of String
      found <- not firstMatch.empty()
      stdout.println(found)

true