Findpath Representation

We will use a Cons representation in which a symbol or String is a file or directory name and a list is a directory whose first element is the directory name and whose rest is the contents.

findpath has two arguments:

• dirtree is a directory tree, a list of items:
  (item₁ ... item_n). Each item_i is:
  • a subdirectory: a list (name item₁ ... item_n)
    (fall06 prog2.r prog1.r grades)
  • a file name: prog2.r
• path is a list of names.
  (/usr bill course cop3212 fall06 grades)

What findpath does is to look through its list to find some item that matches the first name in path:

• If a subdirectory matches, go into that subdirectory.
• If a file matches, done: return that entry.
• If a file does not match, skip it; go to next entry.