Hi there! I'm trying to iterate through each character of a string (that part I can do!) however, I need to apply a transformation to each character...based on the previous character in the string! This is the part I have no clue how to do! I'm totally new to Haskell so I'm pretty sure I'm missing something obvious... I tried with list comprehensions...map... etc... but I can't figure out how I can access the previous character in my string in each "iteration".... to use simple pseudo code, what i need to do is: while i < my_string length: if my_string[i-1] == some_char: do something with my_string[i] else do something else with my_string[i] I'm using imperative programming here obviously since it's what I am familiar with...but any help as to how I could "translate" this to functional programming would be really appreciated! Jean-Nicolas Jolivet