2 music-iterator.hh -- declare Music_iterator
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
10 #ifndef MUSIC_ITERATOR_HH
11 #define MUSIC_ITERATOR_HH
13 #include "lily-proto.hh"
16 #include "virtual-methods.hh"
17 #include "interpretation-context-handle.hh"
23 Music_iterator is an object type that traverses the Music structure and
24 reports the events it finds to interpretation contexts. It is not yet
30 Conceptually a music-iterator operates on a queue of musical events
31 that are pending. This queue does not actually exist, but it is a
32 way of viewing and traversing music-expressions.
35 ok () -- events left ?
37 pending_mom () -- time tag of the next event to be processed.
38 PRECONDITION: this->ok () holds.
40 process (M) -- process all at M (Precondition: no events exist
41 before M, this->ok () holds). Side-effects:
43 * This removes all events at M from the pending queue.
45 * Typically this reports the music to an interpretation context,
46 thus changing the state of the interpretation context.
51 merge pending_moment and process?
60 DECLARE_SMOBS (Music_iterator,dummy);
61 Music_iterator (Music_iterator const&);
64 Moment music_get_length () const;
65 virtual Moment music_start_mom () const;
69 Do the reporting. Will try MUSIC_L_ in its own translator first,
70 then its children. Returns the iterator that succeeded
72 Music_iterator * try_music (Music *) const;
75 The translation unit that we this iterator is reporting to now.
77 Context * get_outlet () const;
79 void set_translator (Context *);
81 /** Get an iterator matching the type of MUS, and use TRANS to find
82 an accompanying translation unit
84 static SCM get_static_get_iterator (Music * mus);
85 void init_translator (Music *, Context *);
87 void substitute_outlet (Context * from, Context *to);
88 virtual void derived_substitute (Context *, Context *);
89 virtual Moment pending_moment () const;
90 virtual bool ok () const;
92 virtual bool run_always () const;
93 virtual void process (Moment until);
94 virtual void derived_mark ()const;
95 virtual void construct_children ();
98 Construct sub-iterators, and set the translator to
102 DECLARE_SCHEME_CALLBACK(constructor, ());
105 Get an iterator for MUS, inheriting the translation unit from THIS.
107 SCM get_iterator (Music *) const;
109 virtual Music_iterator* try_music_in_children (Music *) const;
111 Music * get_music () const;
113 virtual void do_quit();
114 void descend_to_child (Context*);
116 Interpretation_context_handle handle_;
120 bool is_child_context (Context *me, Context *child);
122 #define IMPLEMENT_CTOR_CALLBACK(Class) \
123 LY_DEFINE_MEMBER_FUNCTION(Class,constructor, #Class "::constructor",\
128 SCM val = (new Class)->self_scm(); \
129 scm_gc_unprotect_object (val);\
133 DECLARE_UNSMOB(Music_iterator, iterator);
135 #endif // MUSIC_ITERATOR_HH