Doc: Clarify Context creation (3006)

[lilypond.git] / Documentation / extending / programming-interface.itely

diff --git a/Documentation/extending/programming-interface.itely b/Documentation/extending/programming-interface.itely
index 53134bbd8298b66f6404aa0ab09ca02d1aa7b291..9fd578b2bd6262f0a42963f64f32c70392f5271c 100644 (file)
--- a/Documentation/extending/programming-interface.itely
+++ b/Documentation/extending/programming-interface.itely
@@ -1028,19 +1028,18 @@ current bar number on the standard output during the compile:
 @cindex calling code on layout objects
 @funindex \applyOutput
 
-
 The most versatile way of tuning an object is @code{\applyOutput} which
 works by inserting an event into the specified context
 (@rinternals{ApplyOutputEvent}).  Its syntax is
 @example
-\applyOutput @var{context} @var{proc}
+\applyOutput @var{Context} @var{proc}
 @end example
 
 @noindent
 where @code{@var{proc}} is a Scheme function, taking three arguments.
 
 When interpreted, the function @code{@var{proc}} is called for
-every layout object found in the context @code{@var{context}} at
+every layout object found in the context @code{@var{Context}} at
 the current time step, with the following arguments:
 @itemize
 @item the layout object itself,
@@ -1069,6 +1068,14 @@ note-heads on the center-line and next to it:
 }
 @end lilypond
 
+To have @var{function} interpreted at the @code{Score} or @code{Staff}
+level use these forms
+
+@example
+\applyOutput #'Score #@var{function}
+\applyOutput #'Staff #@var{function}
+@end example
+
 
 @node Callback functions
 @section Callback functions
@@ -1281,9 +1288,10 @@ and @code{PaperColumn}.  They can be changed with the
 
 @example
 \overrideProperty
-Score.NonMusicalPaperColumn  % Grob name
-#'line-break-system-details     % Property name
-#'((next-padding . 20))         % Value
+Score.NonMusicalPaperColumn       % Grob name
+  . line-break-system-details     % Property name
+  . next-padding                  % Optional subproperty name
+  #20                             % Value
 @end example
 
 Note, however, that @code{\override}, applied to