Key Entry

We use the angle bracket convention to indicate typing actual key on the keyboard. For instance, when the reader sees <ENTER> they should interpret this as an actual key they should type. Note that all keys are given in upper-case. If the reader is expected to use an upper-case "C" instead of a lower-case "c", they will be presented with the key combination <SHIFT><C>.


Color syntax highlighting is used in this text to display blocks of code. The formatting of this display is done in such a way as to invoke in the mind of the reader the feeling of a terminal, thus making an obvious visual distinction in the text. For instance:

(defun fib
  ((0) 0)
  ((1) 1)
    (+ (fib (- n 1))
       (fib (- n 2)))))

Examples such as this one are readily copied and may be pasted without edit into a file or even the LFE REPL itself.

For interactive code, we display the default LFE prompt the reader will see when in the REPL:

lfe> (integer_to_list 42 2)
;; "101010"

We also distinguish the output from the entered LFE code using code comments displayed afer the command.

For shell commands, the commands to enter at the prompt are prefixed by a $ for the prompt. Input and any relevant output are provided as comment strings:

$ echo "I am excited to learn LFE"
# I am excited to learn LFE


This is a severly hoopy frood. With an attitude. He pops up from time to time, generally with good advice. Or simply as a marker for something the authors hope you will pay special note.

Messages of Note

From time to time you will see call-out boxes, aimed at drawing your attention to something of note. There are four differnt types of these:

  • ones that share useful info (blue)
  • ones that highlight something of a momentus nature (green)
  • ones that offer warnings to tred carefully (orange)
  • ones that beg you not to follow a particular path (red)

These messages will take the following forms:


Here you will see a message of general interest that could have a useful or even positive impact on your experience in programming LFE.

The icon associated with this type of message is the "i" in a circle.


Here you will see a message of general celebration for sitations that warrant it, above and beyond the general celebration you will feel writing programs in a distributed Lisp.

The icon assocated with this type of message is that of LiffyBot.


Here you will see a message indicating a known isssue or practice you should avoid if possible.

The icon assocated with this type of message is the "!" in a caution triangle.


Here you will see a message indicating something that could endanger the proper function of an LFE system or threaten the very existence of the universe itself.

The icon assocated with this type of message is "do not enter".