anchor.diff:        false)))
   
   (defun write-all! (path data)
  -  "Writes the string `data` to the file at `PATH`.
  +  "Writes the string `data` to the file at PATH.
      Creates a new file if it doesn't exist and overwrite the file if it does.
      Returns true if it succeeded or false if it failed.
   
  
positive.code:   (write-all-mode! path true false data))
  
  (defun append-lines! (path data)
    "Appends the lines (list of strings) `data` to the file at `PATH`.
     Creates a new file if it doesn't exist.
     Returns true if it succeeded or false if it failed.
  
  
negative.code:     data))
  
  (defun read-all! (path) 
    "Reads the data from the file at PATH and returns it as a string.
     Returns nil if it failed.
  
     ### Example
  