Re: [patch] top level page breaking directives

[Nicolas Sceaux]

Nicolas Sceaux <address@hidden> writes:

> Joe Neeman <address@hidden> writes:
>
>> It would be nice if this generalised to having \forcePageTurn and 
>> \forbidPageTurn commands. The problem is that you always set 
>> page-break-permission and page-turn-permission together. That means that 
>> something like \forbidPageTurn \forcePageBreak will never work because 
>> \forcePageBreak will set page-turn-permission, overriding everything that 
>> \forbidPageTurn does.
>
> Here is a corrected patch.
>
> \forbidPageBreak and \forcePageBreak incluence page breaking, although
> sometimes they are not, whereas \forbidPageTurn and \forcePageTurn seem
> to have no influence at all (using ly:page-turn-breaking).
>
> Are page break and page turn permissions handled by the page breakers as
> "must do" or "may do"? Should page-(turn|break)-penalty also be set?
>
> BTW, using '() as the value for forbidden permission causes some
> problems when using ly:music-property, because with this function '() is
> the value returned when the property is not set. Thus, we cannot
> discriminate between not set value and the actual '() value. That's why
> I've used 'forbid in the definition of the commands.
>
> nicolas

A new patch:

 - \pageBreak, \noPageBreak, etc, can be used at top-level or inside a
 score, as Mats suggested;

 - the issue regarding the (sometimes) ineffectiveness of \pageBreak at
 toplevel is fixed by specifying a line-break-permission='force, though
 I don't understand why it is required;

 - \pageTurn and \noPageTurn seem to be as effective at top-level as
 they are inside a score.

However, an issue is remaining: Composite_music is not allowed inside a
\book block, so the page breaking commands cannot be used between scores
inside a \book block. Side question: are regression tests containing
serveral \score blocks required to have a \book block?

nicolas

diff --git a/lily/book.cc b/lily/book.cc
index bf28d1b..265632a 100644
--- a/lily/book.cc
+++ b/lily/book.cc
@@ -20,6 +20,7 @@ using namespace std;
 #include "warn.hh"
 #include "performance.hh"
 #include "paper-score.hh"
+#include "page-marker.hh"
 
 #include "ly-smobs.icc"
 
@@ -153,7 +154,8 @@ Book::process (Output_def *default_paper
              outputs = scm_cdr (outputs);
            }
        }
-      else if (Text_interface::is_markup (scm_car (s)))
+      else if (Text_interface::is_markup (scm_car (s))
+              || unsmob_page_marker (scm_car (s)))
        paper_book->add_score (scm_car (s));
       else
        assert (0);
diff --git a/lily/include/page-marker.hh b/lily/include/page-marker.hh
new file mode 100644
index 0000000..a925a6c
--- /dev/null
+++ b/lily/include/page-marker.hh
@@ -0,0 +1,30 @@
+/*
+  page-marker.hh -- declare Page_marker
+
+  source file of the GNU LilyPond music typesetter
+
+  (c) 2007 Nicolas Sceaux <address@hidden>
+*/
+
+#ifndef PAGE_MARKER_HH
+#define PAGE_MARKER_HH
+
+#include "smobs.hh"
+
+class Page_marker
+{
+  DECLARE_SMOBS (Page_marker);
+
+  SCM symbol_; /* either 'page-turn-permission or 'page-break-permission */
+  SCM permission_;  /* 'force, 'allow, or '() */
+
+public:
+  Page_marker (SCM symbol, SCM permission);
+  
+  SCM permission_symbol ();
+  SCM permission_value ();
+};
+
+DECLARE_UNSMOB (Page_marker, page_marker)
+
+#endif /* PAGE_MARKER_HH */
diff --git a/lily/page-marker-scheme.cc b/lily/page-marker-scheme.cc
new file mode 100644
index 0000000..3278a7b
--- /dev/null
+++ b/lily/page-marker-scheme.cc
@@ -0,0 +1,19 @@
+/*
+  page-marker-scheme.cc -- implement Page_marker bindings.
+
+  source file of the GNU LilyPond music typesetter
+
+  (c) 2007 Nicolas Sceaux <address@hidden>
+*/
+
+#include "page-marker.hh"
+
+LY_DEFINE (ly_make_page_marker, "ly:make-page-marker",
+          2, 0, 0,
+          (SCM symbol, SCM permission),
+          "Return page marker with page breaking and turning permissions.")
+{
+  LY_ASSERT_TYPE (ly_is_symbol, symbol, 1);
+  Page_marker *page_marker = new Page_marker (symbol, permission);
+  return page_marker->unprotect ();
+}
diff --git a/lily/page-marker.cc b/lily/page-marker.cc
new file mode 100644
index 0000000..dd43c35
--- /dev/null
+++ b/lily/page-marker.cc
@@ -0,0 +1,55 @@
+/*
+  page-marker.cc -- implement Page_marker
+
+  source file of the GNU LilyPond music typesetter
+
+  (c) 2007 Nicolas Sceaux <address@hidden>
+*/
+
+#include "page-marker.hh"
+#include "ly-smobs.icc"
+
+Page_marker::Page_marker (SCM symbol, SCM permission)
+{
+  symbol_ = symbol;
+  permission_ = permission;
+  smobify_self ();
+}
+
+Page_marker::~Page_marker ()
+{
+}
+
+IMPLEMENT_SMOBS (Page_marker);
+IMPLEMENT_DEFAULT_EQUAL_P (Page_marker);
+IMPLEMENT_TYPE_P (Page_marker, "ly:page-marker?");
+
+SCM
+Page_marker::mark_smob (SCM smob)
+{
+  Page_marker *pm = (Page_marker *) SCM_CELL_WORD_1 (smob);
+  scm_gc_mark (pm->symbol_);
+  scm_gc_mark (pm->permission_);
+  return SCM_EOL;
+}
+
+int
+Page_marker::print_smob (SCM smob, SCM port, scm_print_state*)
+{
+  Page_marker *pm = (Page_marker *) SCM_CELL_WORD_1 (smob);
+  (void)pm;
+  scm_puts ("#<Page_marker>", port);
+  return 1;
+}
+
+SCM
+Page_marker::permission_symbol ()
+{
+  return symbol_;
+}
+
+SCM
+Page_marker::permission_value ()
+{
+  return permission_;
+}
diff --git a/lily/paper-book.cc b/lily/paper-book.cc
index c6bcccd..95be368 100644
--- a/lily/paper-book.cc
+++ b/lily/paper-book.cc
@@ -17,6 +17,7 @@
 #include "text-interface.hh"
 #include "warn.hh"
 #include "program-option.hh"
+#include "page-marker.hh"
 
 #include "ly-smobs.icc"
 
@@ -226,8 +227,25 @@ Paper_book::score_title (SCM header)
   return title;
 }
 
+void
+set_page_permission (SCM sys, SCM symbol, SCM permission)
+{
+  if (Paper_score *ps = dynamic_cast<Paper_score*> (unsmob_music_output (sys)))
+    {
+      vector<Grob*> cols = ps->get_columns ();
+      if (cols.size ())
+       {
+         Paper_column *col = dynamic_cast<Paper_column*> (cols.back ());
+         col->set_property (symbol, permission);
+         col->find_prebroken_piece (LEFT)->set_property (symbol, permission);
+       }
+    }
+  else if (Prob *pb = unsmob_prob (sys))
+    pb->set_property (symbol, permission);
+}
+
 /* read the breakbefore property of a score block and set up the preceding
-   system-spec to honour it. That is, SYM should be the system spec that
+   system-spec to honour it. That is, SYS should be the system spec that
    immediately precedes the score (from which HEADER is taken)
    in the get_system_specs () list */
 void
@@ -239,26 +257,19 @@ set_system_penalty (SCM sys, SCM header)
       if (SCM_VARIABLEP (force)
          && scm_is_bool (SCM_VARIABLE_REF (force)))
        {
-         bool b = to_boolean (SCM_VARIABLE_REF (force));
-         SCM sym = b ? ly_symbol2scm ("force") : SCM_EOL;
-
-         if (Paper_score *ps = dynamic_cast<Paper_score*> (unsmob_music_output 
(sys)))
+         if (to_boolean (SCM_VARIABLE_REF (force)))
            {
-             vector<Grob*> cols = ps->get_columns ();
-             if (cols.size ())
-               {
-                 Paper_column *col = dynamic_cast<Paper_column*> (cols.back 
());
-                 col->set_property ("page-break-permission", sym);
-                 col->find_prebroken_piece (LEFT)->set_property 
("page-break-permission", sym);
-               }
+             set_page_permission (sys, ly_symbol2scm ("page-break-permission"),
+                                  ly_symbol2scm ("force"));
+             set_page_permission (sys, ly_symbol2scm ("line-break-permission"),
+                                  ly_symbol2scm ("force"));
            }
-         else if (Prob *pb = unsmob_prob (sys))
-           pb->set_property ("page-break-permission", sym);
+         else
+           set_page_permission (sys, ly_symbol2scm ("page-break-permission"), 
SCM_EOL);
        }
     }
 }
 
-
 SCM
 Paper_book::get_score_title (SCM header)
 {
@@ -311,6 +322,14 @@ Paper_book::get_system_specs ()
          if (header_0_ == SCM_EOL)
            header_0_ = header;
        }
+      else if (Page_marker *page_marker = unsmob_page_marker (scm_car (s)))
+       {
+         /* a page marker: set previous element page break or turn permission 
*/
+         if (scm_is_pair (system_specs))
+           set_page_permission (scm_car (system_specs),
+                                page_marker->permission_symbol (),
+                                page_marker->permission_value ());
+       }
       else if (Music_output *mop = unsmob_music_output (scm_car (s)))
        {
          if (Paper_score *pscore = dynamic_cast<Paper_score *> (mop))
@@ -344,9 +363,6 @@ Paper_book::get_system_specs ()
          
          // TODO: init props
          Prob *ps = make_paper_system (SCM_EOL);
-         /* we don't have a way of specifying page-{break,turn} on
-            markup blocks, so for now we just set everything turnable
-           and breakable by default */
          ps->set_property ("page-break-permission", ly_symbol2scm ("allow"));
          ps->set_property ("page-turn-permission", ly_symbol2scm ("allow"));
          
diff --git a/ly/declarations-init.ly b/ly/declarations-init.ly
index 1732952..41c3c14 100644
--- a/ly/declarations-init.ly
+++ b/ly/declarations-init.ly
@@ -38,15 +38,8 @@ center = #0
 %% rather name \newline, \pageBreak ?
 break = #(make-event-chord (list (make-music 'LineBreakEvent 'break-permission 
'force)))
 noBreak = #(make-event-chord (list (make-music 'LineBreakEvent 
'break-permission '())))
-pageBreak = #(make-event-chord (list
-                               (make-music 'LineBreakEvent 'break-permission 
'force)
-                               (make-music 'PageBreakEvent 'break-permission 
'force)))
-noPageBreak = #(make-event-chord (list (make-music 'PageBreakEvent 
'break-permission '())))
-pageTurn = #(make-event-chord (list
-                               (make-music 'LineBreakEvent 'break-permission 
'force)
-                               (make-music 'PageBreakEvent 'break-permission 
'force)
-                               (make-music 'PageTurnEvent 'break-permission 
'force)))
-noPageTurn = #(make-event-chord (list (make-music 'PageTurnEvent 
'break-permission '())))
+%% \pageBreak, \noPageBreak, \pageTurn, \noPageTurn, \allowPageTurn are defined
+%% as music functions
 allowPageTurn = #(make-event-chord (list (make-music 'PageTurnEvent 
'break-permission 'allow)))
 
 stopStaff = #(make-event-chord (list (make-span-event 'StaffSpanEvent STOP)))
diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly
index e6aad14..2a1fe13 100644
--- a/ly/music-functions-init.ly
+++ b/ly/music-functions-init.ly
@@ -349,6 +349,65 @@ or @code{\"GrobName\"}")
                        grob-name)
                       (set! (ly:grob-property grob property) value))))))
 
+%% These are music functions (iso music indentifiers), because music 
identifiers
+%% are not allowed at top-level.
+pageBreak =
+#(define-music-function (location parser) ()
+   (_i "Force a page break. May be used at toplevel (ie between scores or
+markups), or inside a score.")
+   (make-music 'EventChord
+              'page-marker #t
+              'line-break-permission 'force
+              'page-break-permission 'force
+              'elements (list (make-music 'LineBreakEvent
+                                          'break-permission 'force)
+                              (make-music 'PageBreakEvent
+                                          'break-permission 'force))))
+
+noPageBreak =
+#(define-music-function (location parser) ()
+   (_i "Forbid a page break. May be used at toplevel (ie between scores or
+markups), or inside a score.")
+   (make-music 'EventChord
+              'page-marker #t
+              'page-break-permission 'forbid
+              'elements (list (make-music 'PageBreakEvent
+                                          'break-permission '()))))
+
+pageTurn =
+#(define-music-function (location parser) ()
+   (_i "Force a page turn between two scores or top-level markups.")
+   (make-music 'EventChord 
+              'page-marker #t
+              'line-break-permission 'force
+              'page-break-permission 'force
+              'page-turn-permission 'force
+              'elements (list (make-music 'LineBreakEvent
+                                          'break-permission 'force)
+                              (make-music 'PageBreakEvent
+                                          'break-permission 'force)
+                              (make-music 'PageTurnEvent
+                                          'break-permission 'force))))
+
+noPageTurn =
+#(define-music-function (location parser) ()
+   (_i "Forbid a page turn. May be used at toplevel (ie between scores or
+markups), or inside a score.")
+   (make-music 'EventChord
+              'page-marker #t
+              'page-turn-permission 'forbid
+              'elements (list (make-music 'PageTurnEvent
+                                          'break-permission '()))))
+
+allowPageTurn =
+#(define-music-function (location parser) ()
+   (_i "Allow a page turn. May be used at toplevel (ie between scores or
+markups), or inside a score.")
+   (make-music 'EventChord
+              'page-marker #t
+              'page-turn-permission 'forbid
+              'elements (list (make-music 'PageTurnEvent
+                                          'break-permission 'allow))))
 
 removeWithTag = 
 #(define-music-function
diff --git a/scm/lily-library.scm b/scm/lily-library.scm
index e6215b9..2758825 100644
--- a/scm/lily-library.scm
+++ b/scm/lily-library.scm
@@ -64,10 +64,28 @@
    (cons score (ly:parser-lookup parser 'toplevel-scores))))
 
 (define-public (collect-music-for-book parser music)
-  ;; discard music if its 'void property is true.
-  (let ((void-music (ly:music-property music 'void)))
-    (if (or (null? void-music) (not void-music))
-        (collect-scores-for-book parser (scorify-music music parser)))))
+  (define (music-property symbol)
+    (let ((value (ly:music-property music symbol)))
+      (if (not (null? value))
+         value
+         #f)))
+  (cond ((music-property 'page-marker)
+        ;; a page marker: set page break/turn permissions
+        (for-each (lambda (symbol)
+                    (let ((permission (music-property symbol)))
+                      (if (symbol? permission)
+                          (collect-scores-for-book
+                           parser
+                           (ly:make-page-marker symbol
+                                                (if (eqv? 'forbid permission)
+                                                    '()
+                                                    permission))))))
+                  (list 'line-break-permission 'page-break-permission
+                         'page-turn-permission)))
+       ((not (music-property 'void))
+        ;; a regular music expression: make a score with this music
+        ;; void music is discarded
+        (collect-scores-for-book parser (scorify-music music parser)))))
 
 (define-public (scorify-music music parser)
   "Preprocess MUSIC."