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(librep.info)Macros

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Macros
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   "Macros" are used to extend the Lisp language. They consist of a
function which instead of returning a computed value, transform their
unevaluated arguments into a new form that, when evaluated, produces
the actual value of the original form.

   For example, the `when' macro (Note: Conditional Structures)
implements a new conditional operation by transforming its arguments
into a `cond' statement. That is,

     (when CONDITION FORM ...)
         ==> (cond (CONDITION FORM ...))

   Since macros do not evaluate their arguments, instead just
transforming them, they may be expanded at _compile-time_. The
resulting form is then compiled as usual.

 - Function: macrop arg
     Returns true if ARG is a macro object.

Defining Macros

Macros are defined like functions

Backquoting

Creating macros from templates

Macro Expansion

How macros are used by the evaluator

Compiling Macros

The compiler expands macros at compile-

time.