lily/include/music-iterator.hh

   1 /*
   2   music-iterator.hh -- declare Music_iterator
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2001 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9
  10 #ifndef MUSIC_ITERATOR_HH
  11 #define MUSIC_ITERATOR_HH
  12
  13 #include "lily-proto.hh"
  14 #include "array.hh"
  15 #include "moment.hh"
  16 #include "virtual-methods.hh"
  17 #include "interpretation-context-handle.hh"
  18 #include "cxx-function-smob.hh"
  19
  20 /**
  21   Conceptually a music-iterator operates on a queue of musical events
  22   that are pending. This queue does not actually exist, but it is a
  23   way of viewing and traversing music-expressions.
  24
  25
  26   ok () -- events left ?
  27
  28   pending_mom () -- time tag of the next event to be processed.
  29     PRECONDITION: this->ok () holds.
  30
  31   process (M) -- process all at M (Precondition: no events exist
  32     before M, this->ok () holds).  Side-effects:
  33
  34     * This removes all events at M from the pending queue.
  35
  36     * Typically this reports the music to an interpretation context,
  37     thus changing the state of the interpretation context.
  38
  39   get_music (M) -- return all events starting at M (pre: no events
  40     before M). No side-effects
  41
  42   skip (M) -- remove all events starting before M (leave the ones that
  43     start M).  no side-effects on interpretation context
  44
  45
  46   TODO:
  47
  48   merge pending_moment and process?
  49
  50 */
  51 class Music_iterator
  52 {
  53 protected:
  54   Moment music_length_;
  55   Moment start_mom_;
  56 public:
  57   VIRTUAL_COPY_CONS (Music_iterator);
  58
  59   Moment music_length_mom () const;
  60   Moment music_start_mom () const;
  61   Music_iterator ();
  62   Music_iterator (Music_iterator const&);
  63   virtual ~Music_iterator ();
  64
  65   /**
  66      Do the reporting.  Will try MUSIC_L_ in its own translator first,
  67      then its children. Returns the iterator that succeeded
  68   */
  69   Music_iterator *  try_music (Music  *) const;
  70
  71   /**
  72     The translation unit that we this iterator is reporting  to now.
  73    */
  74   Translator_group* report_to_l () const;
  75
  76   void set_translator (Translator_group*);
  77
  78   /** Get an iterator matching the type of MUS, and use TRANS to find
  79     an accompanying translation unit
  80    */
  81   static Music_iterator* static_get_iterator_p (Music * mus);
  82   void init_translator (Music  *, Translator_group *);
  83
  84   virtual Moment pending_moment () const;
  85   virtual bool ok () const;
  86   virtual SCM get_music (Moment until)const;
  87   virtual void process (Moment until);
  88   virtual void skip (Moment until);
  89
  90   /**
  91     Construct sub-iterators, and set the translator to
  92     report to.
  93    */
  94   virtual void construct_children ();
  95   static SCM constructor_cxx_function;
  96
  97   /**
  98     Get an iterator for MUS, inheriting the translation unit from THIS.
  99    */
 100   Music_iterator* get_iterator_p (Music *) const;
 101
 102   virtual Music_iterator* try_music_in_children (Music *) const;
 103
 104   Music * music_l () const;
 105 private:
 106   Interpretation_context_handle handle_;
 107   Music  * music_l_;
 108 };
 109
 110
 111 /*
 112   implement Class::constructor, a SCM function that
 113   returns an encapsulated factory function.
 114  */
 115 #define IMPLEMENT_CTOR_CALLBACK(Class)          \
 116 static void *                                           \
 117 Class ## _ctor (SCM)                            \
 118 {                                               \
 119   return new Class ;                            \
 120 }                                               \
 121 SCM Class :: constructor_cxx_function;\
 122 void                                            \
 123 Class ## _constructor_init ()                           \
 124 {                                               \
 125   SCM s = smobify_cxx_function (& Class ## _ctor);      \
 126   scm_permanent_object (s);\
 127   gh_define (#Class "::constructor", s);\
 128   Class :: constructor_cxx_function = s;\
 129 }\
 130 ADD_SCM_INIT_FUNC (Class ## _ctor_init, Class ## _constructor_init);
 131
 132
 133
 134
 135
 136
 137
 138 #endif // MUSIC_ITERATOR_HH