macroexpand-1

Type:	-	function (subr)
Source:	-	xlbfun.c

Syntax

(macroexpand-1 form)

form - a macro form
returns - the macro expansion

Description

The 'macroexpand-1' function takes a 'form' and expands the first level of the macro definition used in the 'form'. The function returns the expansion. If the 'form' does not contain a macro, the form is returned unaltered.

Examples

(defmacro plus (n1 n2) `(+ ,n1 ,n2))   ; define PLUS macro
(plus 1 2)                             ; returns 3
(macroexpand '(plus 3 4))              ; returns (+ 3 4)
(macroexpand-1 '(plus 3 4))            ; returns (+ 3 4)

(defmacro pl (p1 p2) `(plus ,p1 ,p2))  ; define PL macro using PLUS
(pl 3 4)                               ; returns 7
(macroexpand '(pl 3 4))                ; returns (+ 3 4)
(macroexpand-1 '(pl 3 4))              ; returns (PLUS 3 4)

Common Lisp: Common Lisp returns 2 values for its result of 'macroexpand-1', the expanded form and a  T  or NIL value that indicates if the form was a macro. XLISP returns only the expanded form. Common Lisp also supports an optional argument in 'macroexpand-1' for the environment of the expansion. XLISP does not support this optional argument.

See the macroexpand-1 function in the XLISP 2.0 manual.

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