Import guile-1.8 as multiple upstream tarball component

[lilypond.git] / guile18 / examples / box-dynamic-module / box-mixed.scm

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+;;; examples/box-dynamic-module/box-mixed.scm -- Scheme module using some
+;;;   functionality from the shared library libbox-module, but do not
+;;;   export procedures from the module.
+
+;;; Commentary:
+
+;;; This is the Scheme module box-mixed.  It uses some functionality
+;;; from the shared library libbox-module, but does not export it.
+
+;;; Code:
+
+;;; Author: Thomas Wawrzinek
+;;; Date: 2001-06-08
+;;; Changed: 2001-06-14 by martin, some commenting, cleanup and integration.
+
+(define-module (box-mixed))
+
+;; First, load the library.
+;;
+(load-extension "libbox-module" "scm_init_box")
+
+;; Create a list of boxes, each containing one element from ARGS.
+;;
+(define (make-box-list . args)
+  (map (lambda (el)
+        (let ((b (make-box)))
+          (box-set! b el) b))
+       args))
+
+;; Map the procedure FUNC over all elements of LST, which must be a
+;; list of boxes.  The result is a list of freshly allocated boxes,
+;; each containing the result of an application of FUNC.
+(define (box-map func lst)
+  (map (lambda (el)
+        (let ((b (make-box)))
+          (box-set! b (func (box-ref el)))
+          b))
+       lst))
+
+;; Export the procedures, so that they can be used by others.
+;;
+(export make-box-list box-map)
+
+;;; End of file.