-Features you cannot find in the doco as working, should be mentioned here.
-
+Features you cannot find in the doco as working, should be mentioned
+here.
+
This is an assorted collection of stuff that will be done, might be
done, or is an idea that I want to think about
Most of the items are marked in the code as well, with full explanation.
-grep for TODO and ugh/ugr
+grep for TODO and ugh/ugr/urg
+
+*In a piece such as the Zipoli piece in mutopia/... there is a stray
+`8' over every bar line when processed by LilyPond 1.1.25.
+
+TODO before 1.2
+
+ - cf'able ly2dvi tagline.
+
+ - make ly2dvi test page.
+
+ - fix dynamics decently, ie. use kerning & ligatures. Junk
+TeX macros.
+
+
+ - span bars. ->gallina
+
+*******
+m=\notes\relative c'{
+\voiceone
+c1
+\mark "A"; R1*3 \mark "B";
+<{R1*3}{s1 \mark "C";}>
+}
+
+n=\notes\relative c'{
+\voicetwo
+c1 | c1 | c1 | c1 | c1 | c1 | c1 |
+}
+
+\score{
+ \type StaffGroup <
+ \type Staff = m <\m>
+ \type Staff = n <\n>
+ >
+
+ \paper {
+ \translator { \OrchestralScoreContext
+ markScriptPadding = "4.0";
+ }
+ }
+}
+*********
+
+ * junk Text_def, use G_text_item in stead.
+
+ * junk Script_def
+
+ * fix partial measures in meaningful way.
+
+ * fix AFM for BlueSky AFM files.
+
+ * working notehead style.
+
+ * add scripts to bars eg. |^"bla"
+
+ * relative mode for mi2mu
+
+ * uniformise recent feta contributions.
+ - use SCM and Molecules for {accordeon stuff, }
+ - bigger and fatter 4/4 C
+
+ * make a SMOB of Atom and Molecule
+
+ * sort out directory stuff.
+ - --prefix option?
+ - -I option per filetype?
+ - kpathsea?
+
+ * is \break broken? input/test/hara-kiri.ly
+
+ * fix OrchestralScore and Hara-kiri (i.e., fix Coriolan)
+
+**************
+I also found a few bugs:
+
+* The examples in input/test/bar-scripts.ly and score-bar-scripts.ly
+ don't work. The problem seems to be that you can't define a
+ a score identifier and then use it in the \score block.
+
+
+ - make separate MF chars for endings of ledger lines, and calc rest of lines.
+
+ * support_l_arr_ empty in staff-margin's G_staff_side_item
+
+ * todo doc left/rightbeamcount
+
+
+ * doc Single_malt_grouping_item
+
+ * ly2dvi/lilypond logfile.
+
+ * remove old preformats in RPM
+
+************
+
+How can I specify a chord whose duration is longer than a whole note?
+
+ \type ChordNames { \chord{ A1*2-min } }
+
+gives me a parse error. And \times doesn't work either. I can't use
+a spacer note. So it seems to be impossible to have long chords of
+general length. Of course, in the example above I can use \breve.
+But what if I want a chord that lasts for 3 whole notes? Or what
+about 2.5 whole notes? Is there a mechanism for getting this kind of
+length?
+
+
+Why does my second extender request get junked in the following:
+
+\score{
+< \notes \relative c''{
+ a4()b()c()d c()d()b()a }
+ \type Lyrics \lyrics {
+ foo1 __ bar2. __ _4 }
+> }
+
+It seems that \cr and \decr don't work any more.
+
+\score{
+ \notes{
+ a \cr b \rc c }
+ \paper{linewidth=-1.;}
+}
+
+Gives me
+
+qq.ly:3:9: warning: can't find (de)crescendo to end:
+ a \cr
+ b \rc c }
+
+
+
+Use of semicolons is still rather confusing. They are obligatory
+after some types of assignments and illegal after others.
+
+ \property foo=bar illegal
+ foo = 3 at top level illegal
+ foo = 3 inside \paper obligatory
+ foo = \notes{ ...} top level illegal
+ foo = \translator{ } in \paper obligatory
+
+As far as I can tell, the sole accomplishment of this syntactic
+irregularity is to keep the user as confused as possible.
+
+
+I was trying to get interstaff beams to work and did this:
+
+\score{
+\type GrandStaff <
+\type Staff=one \notes\relative c'{
+ \stemup
+ [c8 c \translator Staff=two \stemup c c]
+ \translator Staff=one
+ \stemdown
+ [ b8 \translator Staff=two a8]
+ \translator Staff=one
+ c4
+ }
+\type Staff=two \notes{ \clef bass; s1 }
+>
+\paper{
+ \translator{
+ \GrandStaffContext
+ minVerticalAlign = 3.0*\staffheight;
+ maxVerticalAlign = 3.0*\staffheight;
+ }
+ linewidth = -1.;
+}
+}
+
+The beams are at the right angle, but they aren't in the right place.
+
+
+
+*******************
+
+
+ * fractional chord durs.
+
+ * hang Item on Spanner
+
+ * remove Interval dim_ from Dimension_cache and rename the struct.
+
+ * do --safe for PS output?
+
+ * convert-mudela --output
+
+ * Staff_margin (with a partial measure.)
+
+ * fix "I've been drinking too much"
+
+ * fix pletvisibility properties:
+ - bracket on/off/no-bracket-when-beam
+ - num on/off/no-num-when-beam
+
+ * fix: standchen.
+
+ * junk backlinks?
+
+ * junk text{sharp,flat,etc}
+
+ * fix convert-mudela manpage
+
+ * decimal point in \paper {}
+
+ *{ \voiceone <a'4.*2/3 d''4.*2/3 fis''4.*2/3> [g''8 fis'' e''] d''4 |}
+ and=20
+ { \voicetwo d'4 d'2.*2/3 } spacing
+
+ * tied notes for MIDI
+
+ * sharp /flat on trills (in MIDI ??)
+
+ * scm-ify \property values.
+
+ * move class Lookup {} into scm
+
+BUGS:
+
+ * collisions/voices \voiceone \voicetwo are broken; see
+ input/praeludium-fuga-E.ly
+ mutopia/J.S.Bach/wtk1-fugue2.ly
+
+ * fix: text on rests: rediculous dims
+
+ * ly2dvi
+ - bottomnote for ly2dvi
+ - deps for ly2dvi
+
+ * fix midi output:
+ - default duration? duration must be not entered
+ explicitely on first note.
+
+ * turn slope-damping on/off
+
+ * c4 \! \> c4
+
+ * tremolo stuff
+
+ * gallina barlines.
+
+ * fix height of / collisions with lyrics (chords),
+ see input/test/vertical-text.ly; input/test/repeat.ly
+
+ * latex bla.tex broken (titles / \lilyfooter stuff?)
+
+ * msgfmt -o check?
+
+ * \breathmark TeX macro
+
+ * catch GUILE errors?
+
+ * add new glyphs to font.ly
+
+ * formatting of input stuff.
+
+ * \notes{ a \< b \cr } vs \notes{ a \< b \! }
+
+ * if possible, it might be nice for a warning to appear if someone does
+ \translator with no name and without assigning it to an
+ identifier.
+
+ * space after bars?
+
+ * 'hinterfleisch' before bar (e.g. wtk1-fugue2)?
+
+ * \type Voice \times 2/3 { [c8 c16 c16 c16 c16] }
+
+ * fix singleStaffBracket
+
+ * repeat bars: need distance after ":|" and before "|:"
+
+ Summary of minor spelling irregularities:
+ - capitalization/use of underscores in property names
+
+ * fix SkipBars -> skipBars
+
+ * \shape 1st dim skipped?
+
+ * fix marks/barnumbers/marginal notes
+
+ * broken scripts:
+ lbheel = \script { "bheel" 0 0 -1 0 0 }
+ rbheel = \script { "bheel" 0 0 1 0 0 }
+ lbtoe = \script { "btoe" 0 0 -1 0 0 }
+ rbtoe = \script { "btoe" 0 0 1 0 0 }
+ lfheel = \script { "fheel" 0 0 -1 0 0 }
+ rfheel = \script { "fheel" 0 0 1 0 0 }
+ lftoe = \script { "ftoe" 0 0 -1 0 0 }
+ rftoe = \script { "ftoe" 0 0 1 0 0 }
+
+ and also
+
+ portato= \script { "portato" 0 -1 0 1 0 }
+
+STUFF
+ * check out legal/(c) matters for scores.
+
+ * check out GCC signatures?
+
+ * Align_element::padding ?
+
+ * uniformise property names...
+ - ydirection <-> yDirection
+ - rather allow '_' in identifiers first (i.e. junk ^ and _),
+ and do y_direction?
+ - typo checks on property names?
+
+ * use streambufs and iostream
+ to provide IO handling for TeX stream, mudela stream, data-file.
+
+ * seriously buffer TeX output (do profile of writing .5 mb TeX file.)
+
+ * strip EXEs before installing
+
+ * zip target for binary windows dist (JBR)
+
+ * junking \skip req in lyrics
+
+ * Language:
+ - \type -> \context ?
+ - \translator -> ?
+ - fix \partial
+ - \bla {} vs \bla ;
+ - mix engraver hacking with music ?
+ - \once\property KEY = VAL
+ - \addtranslator, \removetranslator
+ - junk ^ and _ for scripts
+ - junk _ for lyrics.
+ - abstract grammar.
+
+ * percussion note heads
+
+ * mi2mu empty staffs.
+
+ * horizontal centering of dynamics
+
+ * \font\fontA=feta20.afm (.afm?)
+
+ * gzip RH manpage
+
+ * stable make/config stuff
+
+ * $DEPENDENCIES_OUTPUT support
+
+ * Xdvi zooming ?! Try to understand GS garbage collection.
+ gs: Error: /undefined in draw_beam
+ gs: Operand stack:
+
+ * fix vertical alignment and stafflines
+
+ * GrandStaff needs more work -- I want a single word
+ `harpsichord' to the left of the grandstaff, not one on each
+ stave. (Organ staff -- with separate pedal -- but common
+ properties may be something to think about. Of course for
+ organ you want to be able to give stop indications on the way
+ through, so the \property Voice.Instrument would be a stop,
+ and \property GrandStaff.instrument would be PipeOrgan...)
+
+ * revise the Score_priority_align_engraver concept. It sucks.
- * LILYSOURCEDIR
+ * make new VoiceOne, VoiceTwo, VoiceThree contexts with
+ydirection and hshift preset
+
+ * *.yo: fix pod manpage layout legacy
+
+ * text-items clash with stems/beams
+
+ * --include, -I option for ly2dvi (pass on to lily)
+
+ * fix placement of beam-less abbrev
+
+ * \meter 3/4;
+ <{\voiceone cis4. cis8 cis4 | cis4 cis cis | r1 }
+ {\voicetwo cis,4 r r | r2. | r1 }> |
+ }
+
+ * try to use template<Type> iso MACRO(Type)
+
+ - NEWS: ... Musical_pitch (analogous to Duration and Rhythmic_req)
+ think about, analogous to pitch:
+ * { a4 a16 } c <-- duration of c?
+ * < a4 b8 > c <-- duration of c?
+
+ * \tempo 4. = 90;
+
+ * fix audio-items (don't use (input) requests, but copy data)
+
+ * make sure all ex's have a mudela-version
+
+ * do rest-collisions for Multi_measure_rests as well.
+
+ * split error/warning in error/warning/non_fatal_error
+
+ * add a Duration_convert member to Duration_iter to set parameters.
+ Junk global duration settings.
+
+ * minimum length second part broken tie
+
+ * en-,discouraged linebreaking:
+ - handle DISALLOW < penalty > FORCE
+ - discourage breaking of slurs
+
+ * fix variable define/lookup parser global<->paper
+
+ * fix title/instrument placements; see input/test/title.ly
+
+ * <\voiceone c4. \voicetwo c4>
+
+ * add full cello suites to web site (kom op, Maarten!)
+
+ * Rethink Time_description
+ * \cadenza , \meter, \grouping should all be \properties
+
+ * rename
+ - measure -> bar
+ - abbrev -> tremolo
+ - abbreviation-beam -> (measured/unmeasured) tremolo
+ - partial -> anacrouse
+
+ * shared lib
+
+ * robustify Beam (in case of no stems, 32nd notes)
+
+ * decentralised spring factory
+
+ * move paper vars into engraver properties
+
+ * check for groff / troff/ nroff et
+
+ * more intelligent file searching
+
+ * make LilyPond RPM fully relocatable
+
+ * disable spaces in TeX stuff
+ * handle ^C for tmp/file creation.
+
+ * dots & rest collisions.
+
* documentation
+ - introduction?
+ - info?
+ - LaTeX?
+ - more manpages?
- * spurious "Junk beam" warnings
+ * versioning for Feta
- * standchen: warning: Excentric column (Meter dims?)
+ * the warning about the negative slur/tie length appears twice
+ which is irritating.
- * optimal pagebreaking.
+ * The `3' in the meter key is a one or two pixels too thin (at 600dpi)
+ in the middle:
+
+ * the bracket is ugly (wings are too parabolic, should be more circular)
+
+ * better hshift (dots, distance, head dependent)
+
+ * clefs (AG): The "8" should appear closer to the actual clef,
+ touching it.
* put errorlevel in Input class
- * AFM for font input?
+ * junk nesting slurs
+
+ * integrate midi-elts from mi2mu and lily?
+
- * naming Mozarella, Madeira, Muella?
+3RD PARTY BUGS:
+****************
+/*
+ICE
+*/
+signature S {
+ int foo ();
+};
- * bf: abbrevs over whole note
+signature V {
+ S * s();
+};
- * scoping for properties
- { c4
- \multi 2 < { \stemup .. } { \stemdown .. } >
- c2
- }
+V*v();
+f ()
+{
+ return v( )->foo ();
+}
+
+/*
+
+ egcs-1.1
+
+foo.cc: In function `int f()':
+foo.cc:6: label `b' used but not defined
+*/
+void
+f ()
+{
+ bool b;
+ if (b && && b)
+ ;
+}
+***************
+
+ * make GCC warn about ctor that leaves member vars uninitialised.
+
+ * GNU diff 2.7: diff -rN does not see a new directory with empty file
+
+ * glibc 2.0:
+
+ f = fopen ("/dev/null", "r")
+ assert (feof (f))
+
+3RD PARTY PROJECTS:
- this modifies \stem for the c2
+ * GNU patch
+ - 'double-fix' mode: ignore identical fix, rather than suggest
+ to revert patch direction when (more or less? exactly) the same
+ thing is fixed
+
+PROJECTS
+
+ * Scripts:
+ - fix position of bar number
+ - stack scripts in chords:
+ % fingering: footing:
+ < a-4 c-2 g-1 > < c-\ltoe e-\lheel >
+ - script-spacing
+ - slur parts as a script
+ - stack parameterised scripts for fingering and footing:
+
+ * convert-mudela:
+ - automatically add a \version if not present.
+ - better parsing
+ - make smarter
+ - convert-mudela -e empty.ly
+
+ * emacs mudela-mode
+ - should handle block comments too.
+ - handle lexer modes (\header, \melodic, \lyric) etc.
+ - indentation
+ - notenames?
+ - fontlock: \melodic \melodic
* use properties for:
- - Text_style
- - default_octave
- plet?
- - default_duration?
- - default abbreviation
- Staff_sym size
- default tempo.
- font size
- bartypes (get rid of derived Span_bar_engravers)
- cadenza mode?
- - MIDI instrument
- - staff title
-
- * give Items/Spanners access to unbroken originals
-
- * Score_bar/Piano_braces, are *not* ordinary bars
-
-3RD PARTY BUGS:
- * Rational infty(HUGE_VAL) on glibc / w32
- * Fix profiling. gprof bugreport?
+ * page handling:
+ - PS output
+ - optimal pagebreaking.
-PROJECTS
-
- * Unicode support?
+ * Unicode support? -> man 7 unicode
- 16 bit Strings
- -u switch
- detect of 16/8 bit files
* Spring_spacer:
- write a faster Spring_spacer (without matrices if possible)
- - use straight QP to find minimal "fitting force"
- relate energybound to linelen unitspace fontsize etc.
- - used fixed point fp
+ - used fixed point fp?
* \header
- - write perl script for handling it into databases
- - write TeX macros to generate titles
- - adapt make-website to use \header info.
-
- * Makefile stuff:
- - Use Automake
- - shared lib on Solaris too.
- - check libtool
- - generate stuff in out/default, out/sun5-irix etc iso out/
- and out-sun5/
-
- * Add mudela-output to Rosegarden.
+ - output header info to MIDI too.
* a musical dictionary. See Documentation/vocabulary-*, other
-languages:
+ languages:
+ - explanations
- italian
- german
- dutch
.. ?
* chords
- - guitar chords
- - chord names
+ - guitar chords (fret diagrams)
+ - other chord name styles (american(?) style)
- basso continuo
- - Syntax/parser
- MIDI output?
- - typesetting
-
- * integrate midi-elts from mi2mu and lily?
* Debug logs:
- derive lily_stream, Dstream, texstream from ostream?
- ABC?
- SMDL?
- * placement of bar-numbers
-
-******************
-
- \score { <
- \melodic \type Staff { c'4 g'4 }
- \lyric { \id "Lyric" ""; hello4 bye4 < a chord > }
- \lyric { \id "Lyric" ""; bye4 hello4 }
- \melodic { \id "Staff" ""; c'4 g'4 }
- > }
-
-******************
-
* add to MIDI output:
- tempo change
- - repeat
+ - ornaments (and trills?)
+ - repeat/volta
- slurs
- - dynamics etc.
+ - accents
+ - dynamics
+ - account for rhythmic position in measure
+ - etc.
* grace notes
- make separate class for Grace_*_engravers
(which is at Voice_gravs level)
- make encapsulated spacing problems.
- * On-demand loading of simple-engravers?
-
* accidentals per Voice_group
- * Convert all ref/bib stuff into BibTeX.
-
* Output class, handles : (smallish)
- help text /(c) notice?
- version line
- quiet/ignore-version options
- logfile output
- * piano staff
-
* elaborate Staff_side baseclass:
- scripts
- text
- slur start/end
+ * PS
+ - speed up PS code.
+ - PS lines to .eps files
+ - write custom prolog
+
* Output an output format independent (ofi) typeset file; and
- make ofi2 TeX, MusixTex, Display PostScript, PostScript,
+ make ofi2 TeX, MusiXTex, Display PostScript, PostScript,
Ascii... interpreters. (difficult)
- - poor man's ascii output possible?
- - MusixTeX output possible? (would have to be done before break calc.)
- NIFF ?
- Common Music Notation
- PostScript output (esp. Beams, Slurs, etc)
- Move all Score_elems, into libmutype.a
-
+ - SGML
+
* Documentation
- - Doc Mutopia (Music To The People)
- Doc (C) stuff of sheet music
- - a tutorial
+ - a better format? SGML? TeX? Info?
+ - a better tutorial
- * TeX spanners , use texbeam.cc as an example (smallish)
+ * more spanners (smallish)
- Glissando
- trill
- - bracket
* Rewrite Stem, Beam and Rhythmic_grouping (hairy)
- [c8. c32 c32]
- separate visual from rhythmic info even more
- beams over bars
- * Redo fonts
- - adapt for multiple font sizes.
-
* lines:
- Ledger lines, should be separate item: Ledger_lines, Ledger_lines
- set different line sizes / thicknesses
* Keys:
- merge key{item} & localkey{item}?
- - do conventional keys (C G A, F B E, a e fis, d as des, etc ),
- besides lists of flats/sharps, possibly via declaration
- - key transposition.
- - key undo: \key bes; .. . \key; should print natural
- - special key: \key bes 'b bis';
- spacing, national styles?
* Support for TAB
* breaking:
- caching breakpoints
- saving them
- - allowing users to set them.
- - penalties
- specify number of lines
- - set linelength per line
-
- * Rhythmic staff.
-
- * Baroque superstaff
-
-SEVERELY LACKING:
-
- * SPEED!
-
- * multibar rests
-
- * markers
-
INPUTLANGUAGE
* relative mode for pitch entering
- * bracket (bracketplets)
-
* configure pitch_byte
* rest name configurable
- * Raw request syntax
-
SMALLISH PROJECTS
+ * limit memory usage; the full coriolan takes up too much resources.
+
+ * fix confusing naming in Engraver vs Engraver_group_engraver (context)
+
* progress when creating MIDI elts.
* A range for context errors (eg. mark both { and }. )
* lyric in staff (sharpsharp in staff, text below)
+ * half sharps/flats
+
* write Dynamic_line (to group dynamics horizontally)
* use Real for all y positions.
+ - use translate_axis( .. ,Y_AXIS) iso separate variables.
* half-sharps, half-flats
* adaptive accidental spacing.
- * unix style paths for LILYINCLUDE env
-
* handle EOF graciously in error messages.
- * caching Item/spanner dimensions.
-
- * centered whole rest
-
- * qtor, btor, mtor-> tor( QUIET_ver ), tor( DEBUG_ver ), etc.
- - use tors feature in lily (?)
-
* declare notenametab?
* midi esp.: use I32 iso int where 32 bits are needed (or assumed...)
- * parshape
-
- * Flower types:
- - A decent scalar type
- - String hash
- - Pointer hash
-
- * binsearch/hash for identifiers
-
* stafftypes: voice names/ instrument names.
- * TeX stuff:
- - Decent TeX titledefs (\tempo, \metron, etc. )
- - decent TeX page layout
-
* lily \tempo
* C meter iso 4/4, idem for alla breve, etc.
* textspanner: center position
- * Brackets
-
- * Scripts:
- - stack scripts in chords:
- % fingering: footing:
- < a-4 c-2 g-1 > < c-\ltoe e-\lheel >
- - script-spacing
- - slur parts as a script
- - stack parameterised scripts for fingering and footing:
-
- % toe to bheel four to five
+ * % toe to bheel four to five
% ^_u 4_5
% -
% --|x-- --|x--
* revise calcideal
- * volta
-
IDEAS
- * Output abstract data structures associated with
-Mudela.
+ * Output data structures of Mudela in XML/SGML.
* create libmudela, or liblily_frontend
* move MIDI stuff (including Quantization) to a ANSI C libmidi library.
- * use an embedded language: Python
- for:
- - Score_elems
- - Engraver
- - Translators
- - Complex mudela?
-
- * y -dims in internote? Staff-space? X-dimensions?
-
* Spacing_request for manually adjusting spacing
* caching breakpoints
- * #c <-> cis
-
- * breath marks
-
* used fixedpoint arithmetic for min. energy.
* move towards incremental algorithms.
- design meta-language like TeX and Metafont
- programming/macros input
- * Global type registration.
-
- My_class * p = create_object( My_class )
- Type t = get_type ( *p );
- if ( t <= get_type( q ))
- ..
-
- * naming of Voice_group/Voice
-
- * benchmark band_matrices.
-
* versioning stuff (cvt mudela, mudela, etc.)
- * a real convert-mudela
-
- * dots into separate item.
-
- * use String iso Text_def for lyrics.
-
- * use position 0 for center of staff iso bottom.
-
* Klavarskribo?
- * lyrics in chords still fuck up.
-
- - rewire acknowledge_element() logic with a process_acknowledged()
-
- * pushgroup/popgroup
-
-
- * multi threading?
- - 1 thread per element/ 1 thread per line
- - 1 thread per Translator
-
- * Use hooks/dependency graphs for properties
+ * dynamic loading of engravers?
+
+SMOBS:
+
+****************************************
+Han-Wen Nienhuys <hanwen@cs.uu.nl> writes:
+
+> mcmanus@IDT.NET writes:
+> > > I want different C++ objects (with scheme embedded) to be linked by
+> > > C++ pointers. I want to access these other objects from the Scheme
+> > > code, and I want access to these pointers from C++.
+> >
+> > You can do this with a combination of smob's and primitive functions,
+> > though it may not be be exactly what you wanted. You would have one
+> > smob for each class in your application, and then you would write a
+> > primitive function that would return the objects that are linked to a
+> > base object.
+>
+> And the smob and the C++ class are interlinked? Like
+>
+> class Foo_class {
+> Foo_smob *smob_ptr_;
+> }
+>
+> struct Foo_smob {
+> Foo_class *class_ptr_
+> }
+
+Usually you can get away without having this interlinked structure.
+One piece of information you need when exporting objects to scheme is
+the smob tag for your class. You might store this value (a long) into
+a class static variable, or a file static variable. I'll use a class
+static variable in this example.
+
+I typically use code that works like this (untested code ahead):
+
+class Foo_class {
+ static long *Foo_smob_tag;
+ SCM obj; // representation as a scheme object, description comes later
+}
+
+// call this once on startup
+void init_Foo_class {
+ static scm_smobfuns type_rec;
+
+ type_rec.mark = foo_mark;
+ type_rec.free = foo_free;
+ type_rec.print = foo_display;
+ type_rec.equalp = 0;
+ Foo_class::Foo_smob_tag = new int(scm_new_smob(type_rec));
+}
+
+When you want to export an object to scheme, you put a pointer to the
+object itself in the cdr of the cell, and the tag in the car of the
+cell. The code looks like this:
+
+// Is this a Foo?
+static int
+foo_p(SCM obj)
+{
+ return(SCM_NIMP(obj) && SCM_CAR(obj) == Foo_class::Foo_smob_tag);
+}
+
+// given a Scheme representation, return, a C++ representation
+static Foo_class *
+foo_unbox(SCM obj)
+{
+ return((Foo_class*)SCM_CDR(obj));
+}
+
+// the SCM representation of the object is stored inside itself
+// this will become useful when destructor gets called
+static SCM
+foo_box(Foo_class *foo)
+{
+ SCM_DEFER_INTS;
+ SCM_NEWCELL(foo->obj);
+ SCM_SETCAR(foo->obj, Foo_class::Foo_smob_tag);
+ SCM_SETCDR(foo->obj, (SCM)foo);
+ SCM_ALLOW_INTS;
+ return foo->obj;
+}
+
+> C++ determines life time, so what is the strategy?
+
+What happens now when the destructor gets called? Lets set the cdr to
+NULL, and then check for that in all of the primitive functions that
+use your smob. We'll call this notion 'live'; a scheme object is
+'live' if the C++ representation still exists, it's dead if the C++
+object is gone. You can still have references to dead objects in
+scheme code; it's just an error to use them. This idea is stolen from
+Emacs's handling of buffers ('buffer-live-p' and friends).
+
+Add another function, foo_live_p:
+
+static int
+foo_live_p(SCM obj)
+{
+ return(foo_p(obj) && SCM_CDR(obj) != NULL);
+}
+
+In you destructor, you need to do:
+
+~Foo_class()
+{
+ SCM_CDR(this->obj, NULL);
+}
+
+When writing new primitives, now just check foo_live_p().
+
+I hope the above helps,
+
+-russ
+
+
+--
+"Even if you are on the right track, you'll get run over
+if you just sit there."
+ --Will Rogers (1879-1935)
+
+***************************
+
+> I am still muddling along with integrating GUILE in LilyPond, and I
+> have a question. I want to replace an existing C++ implementation of
+> identifier tables by GUILE's code. I've managed to replace
+>
+> Hash_table<String,Identifier*>
+>
+> by
+>
+> Hash_table<SCM, Identifier*>
+>
+> and use interning and GUILE symbols for doing the identifier lookup.
+> But I'd like to use GUILE's hash tables as well, and that's were my
+> question comes in: is there an interface that allows me to iterate
+> through the entries of a GUILE hash table?
+
+I use the following, which should definitely be provided somewhere
+in guile, but isn't, AFAIK:
+
+(define (hash-table-for-each fn ht)
+ (do ((i 0 (+ 1 i)))
+ ((= i (vector-length ht)))
+ (do ((alist (vector-ref ht i) (cdr alist)))
+ ((null? alist) #t)
+ (fn (car (car alist)) (cdr (car alist))))))
+
+(define (hash-table-map fn ht)
+ (do ((i 0 (+ 1 i))
+ (ret-ls '()))
+ ((= i (vector-length ht)) (reverse ret-ls))
+ (do ((alist (vector-ref ht i) (cdr alist)))
+ ((null? alist) #t)
+ (set! ret-ls (cons (fn (car (car alist)) (cdr (car alist))) ret-ls)))))
+
+If you want a C version, you can run the above code through hobbit, or
+tranlate it to C by hand.
+
+-russ
+
+
+--
+"Whenever you find yourself on the side of the majority, it is time to
+pause and reflect."
+ -- Mark Twain
+***********************
projects / lilypond.git / blobdiff