2 music-iterator.hh -- declare Music_iterator
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2001 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"
18 #include "cxx-function-smob.hh"
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.
26 ok () -- events left ?
28 pending_mom () -- time tag of the next event to be processed.
29 PRECONDITION: this->ok() holds.
31 process (M) -- process all at M (Precondition: no events exist
32 before M, this->ok() holds). Side-effects:
34 * This removes all events at M from the pending queue.
36 * Typically this reports the music to an interpretation context,
37 thus changing the state of the interpretation context.
39 get_music (M) -- return all events starting at M (pre: no events
40 before M). No side-effects
42 skip (M) -- remove all events starting before M (leave the ones that
43 start M). no side-effects on interpretation context
48 merge pending_moment and process?
57 VIRTUAL_COPY_CONS (Music_iterator);
59 Moment music_length_mom () const;
61 Music_iterator (Music_iterator const&);
62 virtual ~Music_iterator ();
65 Do the reporting. Will try MUSIC_L_ in its own translator first,
66 then its children. Returns the iterator that succeeded
68 Music_iterator * try_music (Music *) const;
71 The translation unit that we this iterator is reporting to now.
73 Translator_group* report_to_l () const;
75 void set_translator (Translator_group*);
77 /** Get an iterator matching the type of MUS, and use TRANS to find
78 an accompanying translation unit
80 static Music_iterator* static_get_iterator_p (Music * mus);
81 void init_translator (Music *, Translator_group *);
83 virtual Moment pending_moment () const;
84 virtual bool ok () const;
85 virtual SCM get_music (Moment until)const;
86 virtual void process (Moment until);
87 virtual void skip (Moment until);
90 Construct sub-iterators, and set the translator to
93 virtual void construct_children ();
94 static SCM constructor_cxx_function;
100 Get an iterator for MUS, inheriting the translation unit from THIS.
102 Music_iterator* get_iterator_p (Music *) const;
104 virtual Music_iterator* try_music_in_children (Music *) const;
107 Interpretation_context_handle handle_;
112 implement Class::constructor, a SCM function that
113 returns an encapsulated factory function.
115 #define IMPLEMENT_CTOR_CALLBACK(Class) \
117 Class ## _ctor (SCM) \
121 SCM Class :: constructor_cxx_function;\
123 Class ## _constructor_init() \
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;\
130 ADD_SCM_INIT_FUNC(Class ## _ctor_init, Class ## _constructor_init);
138 #endif // MUSIC_ITERATOR_HH