flatten-module

-- do the w/w split
consider 'hanoi
{ load "../fib-tuple/WWSplitTactic.hss" }

{ consider 'work
  remember origwork

  any-call (unfold 'unwrap)

  -- establish the zero base case
  down ; down ; down ; down ; down
  case-split-inline 'n
  { 1 ; any-call (unfold 'f) ; simplify }

  -- establish the one base case
  { 2 ; down ; case-split-inline 'a
    { 1 ; any-call (unfold 'f) ; simplify
      any-call (unfold origwork)
      any-call (unfold-rule pc)
      any-call (unfold 'f)
      simplify
      any-call (unfold-rule "[] ++")
      any-call (unfold-rule "++ []")
    }
    { 2 ; any-call (unfold 'f) ; simplify

      any-call (unfold origwork)
      any-call (unfold-rule pc)
      any-call (unfold 'f)
      simplify

      -- recursion decrements by two, so must do this again
      any-call (unfold origwork)
      any-call (unfold-rule pc)

      -- time to let intro
      -- need a "occurance 'work" like consider
      { down
        { 1
          { 0 ; 1
            { 0 ; 1 ; let-intro 'u }
            { 1 ; 1 ; let-intro 'v }
          }
          { 1 ; 1 ; 0 ; 1 ; let-intro 'w }
        }
        innermost let-float
        any-call (fold 'u)
        any-call (fold 'v)
        any-call (fold 'w)
        let-tuple 'uvw
        any-call (fold 'unwrap)
        any-call (fold origwork)
      }
    }
  }
}
innermost dead-code-elimination