Grep for TODO and ugh/ugr/urg.
.* BUGS
-. * .ly files
-. * input/star-spangled-banner
-. * mutopia/J.S.Bach/wtk1-fugue2.ly
-. * input/test/grace
-. * fix: text on rests: ridiculous dims
-. * m=\notes\relative c'''{
- \time 2/4;
-
- R2*4 | c2 | c2 | c2 | c2 | c2 | c2 | c2 | c2 | c2 | \break
- <{R2*10}{s2 \mark "A"; }> | % Too narrow space for the first rest in
-1.1.29
- r4 r8 [g16 \p ( a ] |
-[ ) g8-. fis16 ( g ][ ) fis8-. f16 ( g ] |
-[ ) f8-. e16 ( f ][ ) e8-. es16 ( f ] |
-[ ) es8 \f c16 ( d][es8 d16 c ] |
-) d4 r8 [g16 \p ( a ] |
-[ ) g8-. fis16 ( g ][ ) fis8-. f16 ( g ] | \break
-) c2 | c2 | c2 | c2 | c2 | c2 | c2 | c2 | c2 |
-}
-
-\score{
- \m
- \paper{
- \translator{
- \ScoreContext
- SkipBars = 1;
- }
- \translator {
- \OrchestralPartStaffContext
- }
- }
-}
-. * - Look at input/test/span-bars.ly. The staff lines extend too far
- to the left on the note systems including the GrandStaff.
+. * indent = 0.0 with linewidth=-1.0
+. * PostScript
+. * header for PS enteredby = "bla <bla@bar.com>"
+. * ps/lily.ps see comments.
+. * didot / big point.
. * midi key.
-. *P.P.S. It can be cool in mudela-book to distinguish in pre,postMudelaExample,
-whether MudelaExample is epsed or not: ( if this fragment is floating eps, than 1,
-otherwise 2). say preMudelaExample[eps]{}, and change it in document body sometimes.
-
-. * tetex: mfplain.mem
-. * fix midi output:
-. * default duration? d
- duration must be not entered explicitely on first note.
+. * Repeats
+. * input/bugs/rep.ly (moved from test)
+. * unfold broken:
+. * without alternatives: repeat unfold 4 { a b c d }
+. * count > alternatives: repeat unfold 79 { a b c d }
+\alternative { { c c c c } { d d d d } }
+. * kind of 'initial property' iso fold/volta(semi)/unfold strings
. * fix singleStaffBracket
+. * declare performers in \midi
+. * input/test/stem-spacing.ly: 12/4 touches first note
+4 too high?
+. * fix MIDI
. * \shape 1st dim skipped?
. * turn slope-damping on/off
-. * tremolo stuff
-. * fix height of / collisions with lyrics (chords),
- see input/test/vertical-text.ly; input/test/repeat.ly
. * We need feta-din*.mf files for more sizes than 10.
-. * latex bla.tex broken (titles / \lilyfooter stuff?)
. * fix dynamics decently, ie. use kerning & ligatures.
-. * support_l_arr_ empty in staff-margin's G_staff_side_item
-. * minVerticalAlign for StaffGroups.
-. * fix OrchestralScore and Hara-kiri (i.e., fix Coriolan)
-. * Phrasing: Indicating the textual underlay of a piece, or
-otherwise dividing a piece into phrases.
-
-There are distinct ways of specifying the first two (although at
-present, they're not properly distinguished) but no distinct way to
-specify the third. Should there be?
+. *
+BUGS:
+> +
+> + Causes segfault:
+> +
+> + \score{
+> + \notes{ \context Voice {
+> + \repeat fold 2 { a b c d } {}
+> + }
+> + }
+> + }
+> +
+. * dots & rest collisions?
+. * mudela-book.py
+. * fix \mudelafile{} to have decent functionality
+. * P.P.S. It can be cool in mudela-book to distinguish in
+pre,postMudelaExample, whether MudelaExample is epsed or not: ( if
+this fragment is floating eps, than 1, otherwise 2). say
+preMudelaExample[eps]{}, and change it in document body sometimes.
+. * use less RE's
+. * slurs colllide with lyrics.
+. * junk _ in lyric mode for " "
+. * Lyrics and scripts collide.
+. * a note with a circle after it, meaning:
+
+ note + circle = note + 1/4 of its length
+
+ the circle is like a dot that's not filled in. for example, on
+ page three, the c-sharp on the second line should be a quarter with
+ a circle, not a quarter tied to a sixteenth. is this at all
+ possible with lily?
+. * tuplets that are written as "number : note", for example
+ "3 : [image of a half note here]". possible?
+
+. * Matanya's tips:
+. * don't shorten stems/staffs closer to each other.
+. * accidentals closer to note head
+. * to space the staffs/staffgroups contained in the score.
+. * heavier beams?
+
+.* Cleanups needed
+. * \$ and $ identifier syntax.
+. * Y dimension units: staffspace vs. Point
+. * Beam
+. * Stem
+. * Slur
+. * Rhythmic_grouping
+. * Duration
+. * clef engraver
+. * parser
.* TODO before 1.2
+. * Morally pure LilyPond.
+. * Remove non-free software links.
+. * Remove meta article LilyPond.
+. * break priority setting from SCM.
. * Gade score
. * remove [] in favour of auto-beamer
-. * In the score, the staff lines extend too far to the left.
- This is also illustrated in the second score of span-bars.ly
- as I've pointed out earlier.
-. *m=\notes\relative c''{
- \property Staff.instr = "Instr "
- \key f;
- f4 \p \< g a bes |
- c d e \f \! f |
- f e d c |
- bes \mf a g f \pp
- }
-
-n=\notes\relative c'{
- \property Staff.instr = "Instr "
- \key f;
- f4 \mp g a \< bes |
- c d e \ff \! f |
- f e d c |
- bes \mp a g f \ppp
- }
-
-\score{
- \type StaffGroup <
- \type Staff = a <{\stemup \property Voice.dynamicDir = \down \m}
- {\stemdown \property Voice.dynamicDir = \up \n}>
- >
-}
-. * The minimum distance between different staffs works only within
- StaffGroups, not between StaffGroups. The Gade Score looks quite
- strange on the pages where the Timpani and/or Brass sections don't
- play. I've set the minimum distance with:
- \translator {
- \OrchestralScoreContext
- minVerticalAlign = 2.5*\staffheight;
- }
-
- I sent a copy of the score to the conductor and his reaction was
- that it would be easy to fix some "spacing problems" with Finale,
- if we could convert the score to Finale. I'm not sure what he
- meant, since we just have had mail conversations so far. Maybe
- it's the staff distances I mentioned above.
-
-. * For the trumpet and horn parts, I wrote two parts on the same
- staff line in the score. I haven't managed to get different
- directions of the dynamics for the two parts.
- Voice.dynamicDir seems to set the direction for the full staff.
-. * hangOnClef with non-breakable clefs.
+. * hangOnClef with non-breakable clefs.
. * Aha, the problem is the new TeX code generation for changing fonts.
> (The explanation below is mostly intended for Han-Wen and Jan)
> Before, the font was changed with macros declared separately for
> fontencoding OT1 is for the hyphenation mechanism to work, an
> argument that's clearly irrelevant in our application. Yet we
> see the problem for August.
-. * Check gcc 2.8.1 compatibility
-. * Document source code.
-. * limit memory usage; the full coriolan takes up too much resources.
-. * Sort items after breaking in order of linenumber. Then be more
- eficient with finding
-. * Do Mark & sweep GC for Score_elems
-. * make "in-between" engraver (Tie, Extender)
-. * textWidthFatness property
+. * Abstraction for engravers:
+. * make "in-between" engraver (Tie, Extender)
+. * make wide_spanner_engraver (line_group_spanner, staff_symbol)
+. * do scaled fonts generally
. * The Lilypond accidental symbols are available through the TeX macros,
\textflat, \textsharp and \textnatural defined in the init file
lilyponddefs.tex. All the symbols are defined in the files fetaXX.tex
where XX corresponds to the size. I don't know where (or even if) they
are installed but they are generated in the mf/out/ directory during the
compilation.
-. * compulsory hshift
-. * 1. Can Lily be told where to start numbering?
-. * do scaled fonts.
-. * profile atom smobs
. * make dependencies () a virtual function.
-. * fix Repeated_music design
-. * one big ly2dvi input that includes *all* tests.
-. * Don't use boolean properties (0,1), instead check existence
-of property.
. * store req -> element, element -> element causes for warnings
-. * junk Text_def, use G_text_item in stead.
-. * junk Script_def
+. * include examples in RPM.
. * fix partial measures in meaningful way.
-. * fix AFM for BlueSky AFM files.
-. * working notehead style.
-. * remove links to non-free SW.
-. * 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
. * sort out directory stuff.
. * --prefix option?
. * -I option per filetype?
. * kpathsea?
-. * todo doc left/rightbeamcount
-. * doc Single_malt_grouping_item
. * ly2dvi/lilypond logfile.
-. * 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?
-
-
-
-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 pletvisibility properties:
-. * bracket on/off/no-bracket-when-beam
-. * num on/off/no-num-when-beam
-. * fix: standchen.
-. * 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
+ and
{ \voicetwo d'4 d'2.*2/3 } spacing
. * tied notes for MIDI
-. * sharp /flat on trills (in MIDI ??)
+. * sharp / flat on trills (in MIDI ??)
. * scm-ify \property values.
. * move class Lookup {} into scm
-. * collisions/voices \voiceone \voicetwo are broken; see
. * 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] }
-. * repeat bars: need distance after ":|" and before "|:"
-. * Summary of minor spelling irregularities:
-. * capitalization/use of underscores in property names
-. * fix SkipBars -> skipBars
-
. * broken scripts:
lbheel = \script { "bheel" 0 0 -1 0 0 }
rbheel = \script { "bheel" 0 0 1 0 0 }
portato= \script { "portato" 0 -1 0 1 0 }
. * ly2dvi
. * bottomnote for ly2dvi
-. * cf'able ly2dvi tagline.
. * deps for ly2dvi
+
.* STUFF
+. * compulsory hshift
+. *
+My wish list for lyrics. I dream of a time when I will have enough time to
+become familiar enough with the source code to be able to implement some of
+these myself, but I don't know when that will be, so I thought I'd "publish"
+my suggestions in case someone else is in a position to give them some
+priority. Otherwise, perhaps they could go on the todo list?
+
+If any of these are already implemented, please let me what the syntax is to
+use them!
+
+1. Stanza numbering. Numbering at the beginning of a song with the number
+set to the left of the first note. It would also be nice (but not as
+important) to be able to have some form of automatic numbering at the
+beginning of each new line. This would make it easier to follow songs with a
+large number of stanzas.
+
+2. Hyphens between syllables. At the moment there appears to be no easy way
+to position a hyphen mid-way between the syllables it breaks.
+
+3. Notes centred above/below lyrics rather than left-aligned.
+
+4. It would be very nice to be able to build some kind of phrasing into the
+lyrics of hymns, etc, so that the first words of a phrase are left aligned
+with each other, the last words are right aligned, and the words in between
+are centred.
+
+5. In a song, with (say) four stanzas and a chorus, it would be nice to be
+able to vertically align the chorus midway between the staves.
+
+6. It would be nice to be able to put vertical brackets either side of a
+repeated section with different words for each repeat.
+
+. * Give # lines in linebreaking.
. * arrows on slurs.
+. * rewrite context defs using Scheme
+. * \selectmusic to cut pieces from music.
+. * TODO: merge atom & molecule; make tree from molecule.
. * 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?
+. * 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.
+. * use Fourier transformation for rhythmic quantisation.
. * horizontal centering of dynamics
-. * 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.
-. * make new VoiceOne, VoiceTwo, VoiceThree contexts with
-ydirection and hshift preset
+. * declaring Performers
. * *.yo: fix pod manpage layout legacy
. * text-items clash with stems/beams
. * --include, -I option for ly2dvi (pass on to lily)
<{\voiceone cis4. cis8 cis4 | cis4 cis cis | r1 }
{\voicetwo cis,4 r r | r2. | r1 }> |
}
-. * try to use template<Type> iso MACRO(Type)
-. * Musical_pitch (analogous to Duration and Rhythmic_req)
+. * 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?
. * 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 title/instrument placements; see input/test/title.ly
. * <\voiceone c4. \voicetwo c4>
. * add full cello suites to web site (kom op, Maarten!)
+. * add mudela-book-doc source to webstie.
. * Rethink Time_description
- * \cadenza , \meter, \grouping should all be \properties
+\cadenza , \meter, \grouping should all be \properties
+. * fix singleStaffBracket
. * 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.
+. * make LilyPond RPM fully relocatable
. * dots & rest collisions.
-. * documentation
-. * introduction?
-. * info?
-. * LaTeX?
-. * more manpages?
-. * versioning for Feta
. * the warning about the negative slur/tie length appears twice
- which is irritating.
-. * 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)
+which is irritating.
. * better hshift (dots, distance, head dependent)
. * clefs (AG): The "8" should appear closer to the actual clef,
touching it.
. * put errorlevel in Input class
. * junk nesting slurs
. * integrate midi-elts from mi2mu and lily?
+. * distinguish between unset and empty properties.
+
+.* FONT
+. * the bracket is ugly (wings are too parabolic, should be more circular)
+. * versioning for Feta
+. * rewrite dynamic signs. They're kind of spaghetti now.
+. * The `3' in the meter key is a one or two pixels too thin (at 600dpi)
+ in the middle:
+. * design macro for penstroke with rounded endings
+. * timesig C: fat yet less curved. Check out relations.
+. * design decent macro for bulbed endings
+. * printer dependencies.
+. * versioning
+. * lo-res fixes.
+. * work out sizes of character fonts.
+. * more symbols
+. * piano pedals: Ped/*
+. * maxima notehead
+. * coda signs: Segno, O+
+. * glissando, arpeggio
+. * lengthened trill
+. * include important spacing dims in fetalog
+. * scalability: use blot_diameter everywhere, make font chubbier for
+ small sizes.
+
.* 3RD PARTY BUGS
+. * UMR: Uninitialized memory read
+ This is occurring while in:
+ qst [qsort.c]
+ qsort [libc.so.1]
+ Keyword_table::Keyword_table(Keyword_ent*) [keyword.cc:28]
+ My_lily_lexer::My_lily_lexer() [my-lily-lexer.cc:78]
+ My_lily_parser::parse_file(String,String) [my-lily-parser.cc:54]
+ do_one_file(String,String) [scores.cc:124]
+ Reading 4 bytes from 0xefffeca8 on the stack.
+ Address 0xefffeca8 is 728 bytes below frame pointer in function
. * GNU diff 2.7: diff -rN does not see a new directory with empty file
+. * mf-to-table -> add space before ; in AFM output. (-> check AFM
+ spec. Is this a bug in afm2tfm?)
. * check out GCC signatures?
. * glibc 2.0:
f = fopen ("/dev/null", "r")
assert (feof (f))
+
+. * tetex: mfplain.mem
.* 3RD PARTY PROJECTS:
. * make GCC warn about ctor that leaves member vars uninitialised.
. * GNU patch
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 >
. * fontlock: \melodic \melodic
. * use properties for:
-. * Staff_sym size
. * default tempo.
. * cadenza mode?
. * detect of 16/8 bit files
. * examples to go with it.
-. * Spring_spacer:
-. * write a faster Spring_spacer (without matrices if possible)
-. * relate energybound to linelen unitspace fontsize etc.
-. * used fixed point fp?
-
. * \header
. * output header info to MIDI too.
. * a musical dictionary. See Documentation/vocabulary-*, other
- languages:
+languages:
. * explanations
. * italian
. * german
. * add to MIDI output:
. * tempo change
. * ornaments (and trills?)
-. * repeat/volta
. * slurs
. * accents
. * dynamics
+> Would it be hard to add support for proper dynamics in MIDI output? I
+> would really like to have this feature...
+
+Concretely spoken, for dynamics you have to write a performer
+(Dynamics_performer), that will take the input requests. If I
+understand correctly, every MIDI note played must have its dynamic
+strength set separately. That means the the Dynamics_performer must
+set the strength of every Audio_note it finds. This means that one
+has to modify existing Audio items. The best way of doing this is
+with a broadcast/acknowledge process.
+
+So the best way of handling this, is
+
+ 1 supporting dynamic settings in Audio_note
+
+ 2 Write a Dynamics_performer that will modify
+ any notes it finds to set appropriate strengths.
+
+I'd say that the work involved is not hard, but you have to be fluent
+with C++ and need some insight into the working of Notation Contexts
+and friends. I guess I could do it in a day or so, but if you are not
+so fluent with the inner workings of LilyPond, it could take you some
+more time (A few more days?).
+
+Please note, that I am *not* going to code this myself: my days are
+valuable, and I think I have more interesting things to do than fixing
+the MIDI output (I don't even have a soundcard). But I *do* want to help
+you or other people with implementing this, so if you need help, don't
+hesitate to ask.
. * account for rhythmic position in measure
. * etc.
. * PS lines to .eps files
. * write custom prolog
-. * NIFF ?
-. * Common Music Notation
-. * PostScript output (esp. Beams, Slurs, etc)
-. * Move all Score_elems, into libmutype.a
-. * SGML
+. * SGML input
. * Documentation
+. * remove links to non-free SW.
+. * internal documentation
+. * a general paper.
+. * \properties
+. * left/rightbeamcount
+. * various other new properties.
+. * introduction?
+. * info?
+. * LaTeX?
+. * more manpages?
. * Doc (C) stuff of sheet music
. * a better format? SGML? TeX? Info?
. * a better tutorial
. * specify number of lines
.* INPUTLANGUAGE
-
+. * \rhythms 4 16 16 16 16; c c c c c -> c4 c16 etc.
+. * convention for slurs vs. phrasing marks.
+. * Language:
+. * \translator -> ?
+. * fix \partial
+. * \bla {} vs \bla ;
+. * mix engraver hacking with music ?
+. * \once\property KEY = VAL
+. * input property
+. * abstract grammar.
+. * Figure out semicolons.
. * c4 4 4 4 for c4 c4 c4 c4?
. * <c f a>4 ?
. * Viola mode?
.* SMALLISH PROJECTS
+. * Faulenzer sign (% repeat). Perhaps also use \repeat syntax?
+
. * fix confusing naming in Engraver vs Engraver_group_engraver (context)
. * progress when creating MIDI elts.
. * lyric in staff (sharpsharp in staff, text below)
-. * half sharps/flats
-
. * write Dynamic_line (to group dynamics horizontally)
. * use Real for all y positions.
. * midi esp.: use I32 iso int where 32 bits are needed (or assumed...)
-. * stafftypes: voice names/ instrument names.
-
. * lily \tempo
. * % toe to bheel four to five
(where "to" is a tiny bow)
. * auxilliary file for caching info.
-
. * Text_crescendo
-. * clean solution for staffsize in items.
-
-. * revise calcideal
-
.* IDEAS
. * Output data structures of Mudela in XML/SGML.
. * create libmudela, or liblily_frontend
. * Spacing_request for manually adjusting spacing
. * caching breakpoints
. * used fixedpoint arithmetic for min. energy.
-. * move towards incremental algorithms.
-. * versioning stuff (cvt mudela, mudela, etc.)
-. * 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)
* OUTLINE SETUP
.* .EMACS
projects / lilypond.git / blobdiff