||:: insert :items: (1 2 foo 3 4)
  :: search :for: (1 2 3 4 foo 1 2 3 4 bar)

||:@include: lib/rpn.nv

|:: insert? :items: $x|
	:front: $x
|:: insert|

|:: search? :for: $x|
	:: search for $x
|:: search|

|:: search for $x :found: $x? :bounce:|
|:: search for $x :found: $x?|

|:: search for $x? :target: front? :front: $x?|
	:found: $x
    :: count a step
|:: search for $x? :target: front? :front: $y|
	:back: $y
    :: count a step

|:: search for $x? :target: back? :back: $x?|
	:found: $x
    :: count a step
|:: search for $x? :target: back? :back: $y|
	:front: $y
    :: count a step

|:: search for $x :target: front :bounce:|
	:target: back
	:not found: $x
    :: count a step
|:: search for $x :target: back :bounce:|
	:target: front
	:not found: $x
    :: count a step

|:: search for $x? :target: front|
	:target: back
	:bounce:
|:: search for $x? :target: back|
	:target: front
	:bounce:

|:: search for $x?|
	:target: front

|:: count a step :@rpn data: $x|
    :steps: $x
|:: count a step? :steps: $x|
    :@rpn: ($x 1 +)
|:: count a step?|
    :steps: 0