Unlike most programming languages, Lisp supports parse-time execution of programs, called "read macros" or "reader macros". These are used to extend the syntax either in universal or program-specific ways. For example, the
quoted form (quote
x) operator can be abbreviated as
x. The ' operator can be defined as a read macro which reads the following list and wraps it with quote. Similarly, the
backquote operator (` ) can be defined as a read macro. ==References==