The following extensions are provided by libscheme.

(defmacro NAME (ARG1 ARG2 ...) BODY)            ; syntax

	Add additional syntax.

(flush-output PORT)                             ; function

	Flush output to given port.

(define-struct NAME (FIELD1 FIELD2 ...))        ; syntax

	Defines a structure type and the following functions:

		(make-NAME INIT1 INIT2 ...)     ; constructor
		(NAME? obj)                     ; predicate
		(NAME-FIELD1 INSTANCE)          ; getter
		(NAME-FIELD2 INSTANCE)          ; getter
		(set-NAME-FIELD1! INSTANCE VAL) ; setter
		(set-NAME-FIELD2! INSTANCE VAL) ; setter

