2 music-iterator.hh -- declare Music_iterator
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2003 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.
48 get_pending_events (M) -- return all events starting at M (pre: no events
49 before M). No side-effects
51 skip (M) -- remove all events starting before M (leave the ones that
52 start M). no side-effects on interpretation context
57 merge pending_moment and process?
66 DECLARE_SMOBS (Music_iterator,dummy);
68 VIRTUAL_COPY_CONS (Music_iterator);
70 Moment music_get_length () const;
71 Moment music_start_mom () const;
73 Music_iterator (Music_iterator const&);
76 Do the reporting. Will try MUSIC_L_ in its own translator first,
77 then its children. Returns the iterator that succeeded
79 Music_iterator * try_music (Music *) const;
82 The translation unit that we this iterator is reporting to now.
84 Translator_group* report_to () const;
86 void set_translator (Translator_group*);
88 /** Get an iterator matching the type of MUS, and use TRANS to find
89 an accompanying translation unit
91 static SCM get_static_get_iterator (Music * mus);
92 void init_translator (Music *, Translator_group *);
96 virtual Moment pending_moment () const;
97 virtual bool ok () const;
99 virtual bool run_always () const;
100 virtual SCM get_pending_events (Moment until)const;
101 virtual void process (Moment until);
102 virtual void skip (Moment until);
103 virtual void derived_mark ()const;
104 virtual void construct_children ();
107 Construct sub-iterators, and set the translator to
111 DECLARE_SCHEME_CALLBACK(constructor, ());
114 Get an iterator for MUS, inheriting the translation unit from THIS.
116 SCM get_iterator (Music *) const;
118 virtual Music_iterator* try_music_in_children (Music *) const;
120 Music * get_music () const;
122 virtual void do_quit();
124 Interpretation_context_handle handle_;
129 #define IMPLEMENT_CTOR_CALLBACK(Class) \
130 LY_DEFINE_MEMBER_FUNCTION(Class,constructor, #Class "::constructor",\
133 "Construct a @code{" #Class "} music iterator")\
135 SCM val = (new Class)->self_scm(); \
136 scm_gc_unprotect_object (val);\
140 DECLARE_UNSMOB(Music_iterator, iterator);
142 #endif // MUSIC_ITERATOR_HH