Source code in the logo programming language

to encode :str [:out "||] [:count 0] [:last first :str]
  if empty? :str [output (word :out :count :last)]
  if equal? first :str :last [output (encode bf :str :out :count+1 :last)]
  output (encode bf :str (word :out :count :last) 1 first :str)
end

to reps :n :w
  output ifelse :n = 0 ["||] [word :w reps :n-1 :w]
end
to decode :str [:out "||] [:count 0]
  if empty? :str [output :out]
  if number? first :str [output (decode bf :str :out 10*:count + first :str)]
  output (decode bf :str word :out reps :count first :str)
end

make "foo "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW
make "rle encode :foo
show equal? :foo decode :rle