lily/scheme-engraver.cc

   1 /*
   2   scheme-engraver.cc -- implement Scheme_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   Copyright (c) 2009--2015 Han-Wen Nienhuys <hanwen@lilypond.org>
   7
   8   LilyPond is free software: you can redistribute it and/or modify
   9   it under the terms of the GNU General Public License as published by
  10   the Free Software Foundation, either version 3 of the License, or
  11   (at your option) any later version.
  12
  13   LilyPond is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "scheme-engraver.hh"
  23
  24 #include "grob.hh"
  25
  26 #include "translator.icc"
  27
  28 #include "scm-hash.hh"
  29
  30 Scheme_engraver::Scheme_engraver (SCM definition)
  31 {
  32   initialize_function_ = SCM_EOL;
  33   finalize_function_ = SCM_EOL;
  34
  35   interface_acknowledger_hash_ = SCM_EOL;
  36   interface_end_acknowledger_hash_ = SCM_EOL;
  37
  38   must_be_last_ = false;
  39   per_instance_listeners_ = SCM_EOL;
  40   for (int i = 0; i < TRANSLATOR_METHOD_PRECOMPUTE_COUNT; i++)
  41     precomputable_methods_[i] = SCM_UNDEFINED;
  42
  43   init_from_scheme (definition);
  44 }
  45
  46 Scheme_engraver::~Scheme_engraver ()
  47 {
  48 }
  49
  50 // Extracts the value if callable, if not return SCM_UNDEFINED;
  51 static SCM
  52 callable (SCM symbol, SCM defn)
  53 {
  54   SCM val = ly_assoc_get (symbol, defn, SCM_BOOL_F);
  55   return ly_is_procedure (val) ? val : SCM_UNDEFINED;
  56 }
  57
  58 bool
  59 Scheme_engraver::must_be_last () const
  60 {
  61   return must_be_last_;
  62 }
  63
  64 void
  65 Scheme_engraver::fetch_precomputable_methods (SCM ptrs[])
  66 {
  67   for (int i = 0; i < TRANSLATOR_METHOD_PRECOMPUTE_COUNT; i++)
  68     ptrs[i] = precomputable_methods_[i];
  69 }
  70
  71 void
  72 Scheme_engraver::init_from_scheme (SCM definition)
  73 {
  74   precomputable_methods_[START_TRANSLATION_TIMESTEP]
  75     = callable (ly_symbol2scm ("start-translation-timestep"), definition);
  76   precomputable_methods_[STOP_TRANSLATION_TIMESTEP]
  77     = callable (ly_symbol2scm ("stop-translation-timestep"), definition);
  78   precomputable_methods_[PROCESS_MUSIC]
  79     = callable (ly_symbol2scm ("process-music"), definition);
  80   precomputable_methods_[PROCESS_ACKNOWLEDGED]
  81     = callable (ly_symbol2scm ("process-acknowledged"), definition);
  82   initialize_function_ = callable (ly_symbol2scm ("initialize"), definition);
  83   finalize_function_ = callable (ly_symbol2scm ("finalize"), definition);
  84
  85   SCM p = ly_assoc_get (ly_symbol2scm ("listeners"), definition, SCM_EOL);
  86   SCM listeners = SCM_EOL;
  87
  88   must_be_last_ = to_boolean (ly_assoc_get (ly_symbol2scm ("must-be-last"),
  89                                             definition,
  90                                             SCM_BOOL_F));
  91
  92   for (; scm_is_pair (p); p = scm_cdr (p))
  93     {
  94       SCM event_class = scm_caar (p);
  95       SCM proc = scm_cdar (p);
  96
  97       if (!(ly_is_procedure (proc) && ly_is_symbol (event_class)))
  98         continue;
  99
 100       // We should check the arity of the function?
 101
 102       // Record for later lookup.
 103       listeners = scm_acons (event_class, proc, listeners);
 104     }
 105
 106   SCM hash1 =
 107     init_acknowledgers (ly_assoc_get (ly_symbol2scm ("acknowledgers"),
 108                                       definition, SCM_EOL));
 109   SCM hash2 =
 110     init_acknowledgers (ly_assoc_get (ly_symbol2scm ("end-acknowledgers"),
 111                                       definition, SCM_EOL));
 112
 113   per_instance_listeners_ = listeners;
 114   interface_acknowledger_hash_ = hash1;
 115   interface_end_acknowledger_hash_ = hash2;
 116
 117   // It's not defined whether Scheme_engraver::derived_mark is already
 118   // active while the construction is underway, so we make sure we
 119   // keep a version of everything on the stack that is not still
 120   // covered by `definition'.
 121
 122   scm_remember_upto_here_2 (definition, listeners);
 123   scm_remember_upto_here_2 (hash1, hash2);
 124
 125   // TODO: hook up description, props read/written, grobs created
 126   // etc. to provide automatic documentation.
 127 }
 128
 129 SCM
 130 Scheme_engraver::init_acknowledgers (SCM alist)
 131 {
 132   SCM hash = Scheme_hash_table::make_smob ();
 133   for (SCM p = alist; scm_is_pair (p); p = scm_cdr (p))
 134     {
 135       SCM iface = scm_caar (p);
 136       SCM proc = scm_cdar (p);
 137
 138       if (!(ly_is_procedure (proc) && ly_is_symbol (iface)))
 139         continue;
 140
 141       unsmob<Scheme_hash_table>(hash)->set (iface, proc);
 142     }
 143   return hash;
 144 }
 145
 146 SCM
 147 Scheme_engraver::get_listener_list () const
 148 {
 149   return per_instance_listeners_;
 150 }
 151
 152 void
 153 Scheme_engraver::initialize ()
 154 {
 155   if (!SCM_UNBNDP (initialize_function_))
 156     scm_call_1 (initialize_function_, self_scm ());
 157 }
 158
 159 void
 160 Scheme_engraver::finalize ()
 161 {
 162   if (!SCM_UNBNDP (finalize_function_))
 163     scm_call_1 (finalize_function_, self_scm ());
 164 }
 165
 166 void
 167 Scheme_engraver::derived_mark () const
 168 {
 169   for (int i = 0; i < TRANSLATOR_METHOD_PRECOMPUTE_COUNT; i++)
 170     scm_gc_mark (precomputable_methods_[i]);
 171
 172   scm_gc_mark (initialize_function_);
 173   scm_gc_mark (finalize_function_);
 174   scm_gc_mark (per_instance_listeners_);
 175   scm_gc_mark (interface_acknowledger_hash_);
 176   scm_gc_mark (interface_end_acknowledger_hash_);
 177 }