Page:AIM-514.djvu/6

 this problem we invent a new notation: (QUOTE d) in a program represents the constant datum d. Thus we can write our test as "(EQ X (QUOTE FOO))". Similarly,

(APPEND X (LIST Y Z))

constructs a list from the values of Y and Z, and appends the result to the value of x, while

(APPEND X (QUOTE (LIST Y Z))

appends to the value of x the constant list "(LIST Y Z)". Because the QUOTE construction is used so frequently in LISP, we use an abbreviated notation: "'FOO" ("FOO" with a preceding quote-mark) is equivalent to "(QUOTE FOO)". This is only a notational convenience; the two notations denote the same list.