Issue 5148/2: three-sided-box snippet: use #:properties keyword

diff --git a/Documentation/snippets/new/three-sided-box.ly b/Documentation/snippets/new/three-sided-box.ly
new file mode 100644 (file)
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--- /dev/null
+++ b/Documentation/snippets/new/three-sided-box.ly
@@ -0,0 +1,45 @@
+\version "2.18.0"
+
+\header {
+  lsrtags = "rhythms, scheme-language, text"
+
+  texidoc = "
+This example shows how to add a markup command to get a three sided box
+around some text (or other markup).
+
+"
+  doctitle = "Three-sided box"
+}
+% New command to add a three sided box, with sides north, west and south
+% Based on the box-stencil command defined in scm/stencil.scm
+% Note that ";;" is used to comment a line in Scheme
+#(define-public (NWS-box-stencil stencil thickness padding)
+   "Add a box around STENCIL, producing a new stencil."
+   (let* ((x-ext (interval-widen (ly:stencil-extent stencil X) padding))
+          (y-ext (interval-widen (ly:stencil-extent stencil Y) padding))
+          (y-rule (make-filled-box-stencil (cons 0 thickness) y-ext))
+          (x-rule (make-filled-box-stencil
+                   (interval-widen x-ext thickness) (cons 0 thickness))))
+     ;; (set! stencil (ly:stencil-combine-at-edge stencil X 1 y-rule padding))
+     (set! stencil (ly:stencil-combine-at-edge stencil X LEFT y-rule padding))
+     (set! stencil (ly:stencil-combine-at-edge stencil Y UP x-rule 0.0))
+     (set! stencil (ly:stencil-combine-at-edge stencil Y DOWN x-rule 0.0))
+     stencil))
+
+% The corresponding markup command, based on the \box command defined
+% in scm/define-markup-commands.scm
+#(define-markup-command (NWS-box layout props arg) (markup?)
+   #:properties ((thickness 0.1) (font-size 0) (box-padding 0.2))
+   "Draw a box round @var{arg}.  Looks at @code{thickness},
+@code{box-padding} and @code{font-size} properties to determine line
+thickness and padding around the markup."
+   (let ((pad (* (magstep font-size) box-padding))
+         (m (interpret-markup layout props arg)))
+     (NWS-box-stencil m thickness pad)))
+
+% Test it:
+
+\relative c' {
+  c1^\markup { \NWS-box ABCD }
+  c1^\markup { \NWS-box \note #"4" #1.0 }
+}