Fix ugly output from make-parenthesis-stencil for increased thickness

[lilypond.git] / Documentation / extending / scheme-tutorial.itely

diff --git a/Documentation/extending/scheme-tutorial.itely b/Documentation/extending/scheme-tutorial.itely
index bad8d261b214cd4e6fc1aff56dafbed1af3b6938..8588ff268515d80c7a6d930887cbf00db898c34f 100644 (file)
--- a/Documentation/extending/scheme-tutorial.itely
+++ b/Documentation/extending/scheme-tutorial.itely
@@ -8,7 +8,7 @@
     Guide, node Updating translation committishes..
 @end ignore
 
-@c \version "2.17.11"
+@c \version "2.19.22"
 
 @node Scheme tutorial
 @chapter Scheme tutorial
@@ -275,9 +275,10 @@ Abelson, see
 @node Lists
 @unnumberedsubsubsec Lists
 
-A very common Scheme data structure is the @emph{list}.  Formally, a
-list is defined as either the empty list (represented as @code{'()},
-or a pair whose @code{cdr} is a list.
+A very common Scheme data structure is the @emph{list}.  Formally,
+a @q{proper} list is defined to be either the empty list with its
+input form @code{'()} and length@tie{}0, or a pair whose
+@code{cdr} in turn is a shorter list.
 
 There are many ways of creating lists.  Perhaps the most common is
 with the @code{list} procedure:
@@ -1134,23 +1135,30 @@ will display
 
 By default, LilyPond will print these messages to the console along
 with all the other messages.  To split up these messages and save
-the results of @code{\display@{STUFF@}}, redirect the output to
-a file.
+the results of @code{\display@{STUFF@}}, you can specify an optional
+output port to use:
 
 @example
-lilypond file.ly >display.txt
+@{
+  \displayMusic #(open-output-file "display.txt") @{ c'4\f @}
+@}
 @end example
 
-With a combined bit of Lilypond and Scheme magic, you can actually
-let Lilypond direct just this output to a file of its own:
-
+This will overwrite a previous output file whenever it is called; if you
+need to write more than one expression, you would use a variable for
+your port and reuse it:
 @example
 @{
-  #(with-output-to-file "display.txt"
-      (lambda () #@{ \displayMusic @{ c'4\f @} #@}))
+  port = #(open-output-file "display.txt")
+  \displayMusic \port @{ c'4\f @}
+  \displayMusic \port @{ d'4 @}
+  #(close-output-port port)
 @}
 @end example
 
+Guile's manual describes ports in detail.  Closing the port is actually
+only necessary if you need to read the file before Lilypond finishes; in
+the first example, we did not bother to do so.
 
 A bit of reformatting makes the above information easier to read:
 
@@ -1256,7 +1264,7 @@ The note pitch can be changed by setting this @code{'pitch} property,
        (ly:make-pitch 0 1 0)) ;; set the pitch to d'.
 \displayLilyMusic \someNote
 ===>
-d'
+d'4
 @end example
 
 
@@ -1323,7 +1331,7 @@ property, it is useful to know that an unset property is read out as
 put another element at the front of the @code{articulations} property.
 
 @example
-doubleSlur = #(define-music-function (parser location note) (ly:music?)
+doubleSlur = #(define-music-function (note) (ly:music?)
          "Return: @{ note ( note ) @}.
          `note' is supposed to be a single note."
          (let ((note2 (ly:music-deep-copy note)))
@@ -1499,7 +1507,7 @@ function (a matter of some syntactic sugar and a declaration of the type
 of its sole @q{real} argument).
 
 @example
-addAccent = #(define-music-function (parser location note-event)
+addAccent = #(define-music-function (note-event)
                                      (ly:music?)
   "Add an accent ArticulationEvent to the articulations of `note-event',
   which is supposed to be a NoteEvent expression."
@@ -1544,13 +1552,13 @@ TODO Find a simple example
 
 @ignore
 @lilypond[quote,verbatim,ragged-right]
-padText = #(define-music-function (parser location padding) (number?)
+padText = #(define-music-function (padding) (number?)
 #{
   \once \override TextScript.padding = #padding
 #})
 
-\relative c''' {
-  c4^"piu mosso" b a b
+\relative {
+  c'''4^"piu mosso" b a b
   \padText #1.8
   c4^"piu mosso" d e f
   \padText #2.6
@@ -1567,16 +1575,16 @@ We can use it to create new commands:
 
 
 @lilypond[quote,verbatim,ragged-right]
-tempoPadded = #(define-music-function (parser location padding tempotext)
+tempoPadded = #(define-music-function (padding tempotext)
   (number? markup?)
 #{
   \once \override Score.MetronomeMark.padding = #padding
   \tempo \markup { \bold #tempotext }
 #})
 
-\relative c'' {
+\relative {
   \tempo \markup { "Low tempo" }
-  c4 d e f g1
+  c''4 d e f g1
   \tempoPadded #4.0 "High tempo"
   g4 f e d c1
 }
@@ -1586,7 +1594,7 @@ tempoPadded = #(define-music-function (parser location padding tempotext)
 Even music expressions can be passed in:
 
 @lilypond[quote,verbatim,ragged-right]
-pattern = #(define-music-function (parser location x y) (ly:music? ly:music?)
+pattern = #(define-music-function (x y) (ly:music? ly:music?)
 #{
   #x e8 a b #y b a e
 #})