gistfile1.io

#fib with memoization
fakeClosure := Object clone
fakeClosure memo := Map clone
fakeClosure fibmemo := method(num,
  #I need this next line when i assign this method to a slot in the
  #outer object (see last line of this gist).
  #Feels like a 'this/self' binding issue. Otherwise i would have expected 
  #the memo slot on fakeClosure to be visible here
  memo := fakeClosure memo #not strictly necessary when calling 'fakeClosure fibmemo'
  memo atPut(0 asString, 0)
  memo atPut(1 asString, 1)
  fibhelp := method(num,
    one := memo at((num-1) asString)
    two := memo at((num-2) asString)
    if(one == nil
      , one = fibhelp(num-1,memo)
        memo atPut((num-1) asString, one)
      )
    if(two == nil
      , two = fibhelp(num-2,memo)
        memo atPut((num-2) asString, two)
      )
    one + two
  )
  fibhelp(num,memo)
)
#not really necessary, but i wanted it to be uniform with the other calls
#makes line 9 necessary
fibmemo := fakeClosure getSlot("fibmemo")