accomplish the various stages of the process, is described in this section. A
more complete description of the LilyPond architecture and internal program
execution is found in Erik Sandberg's
-@uref{http://lilypond.org/web/images/thesis-erik-sandberg.pdf, master's
+@uref{http://lilypond.org/website/pdf/thesis-erik-sandberg.pdf, master's
thesis}.
The first stage of LilyPond processing is @emph{parsing}. In the parsing
PostScript is used to generate graphical output. A brief PostScript tutorial
is @uref{http://local.wasp.uwa.edu.au/~pbourke/dataformats/postscript/,
available online}. The
-@uref{http://www.adobe.com/devnet/postscript/pdfs/PLRM.pdf, PostScript Language
+@uref{http://www.adobe.com/products/postscript/pdfs/PLRM.pdf, PostScript Language
Reference} is available online in PDF format.
@subsection Python
When translating, it is preferable to put interesting information
at the end of the message, rather than embedded in the middle.
This especially applies to frequently used messages, even if this
-would mean sacrificing a bit of eloquency. This holds for original
+would mean sacrificing a bit of eloquence. This holds for original
messages too, of course.
@example
@item BASIC_PROGRESS: Warnings, errors and basic progress (success, etc.)
@item PROGRESS: Warnings, errors and full progress messages
@item INFO: Warnings, errors, progress and more detailed information (default)
-@item DEBUG: All messages, including vull debug messages (very verbose!)
+@item DEBUG: All messages, including full debug messages (very verbose!)
@end itemize
The loglevel can either be set with the environment variable
@item Installing graphviz
In order to create the graph of the object relationships, it is
-first necessary to install Graphviz. graphviz is available for a
+first necessary to install Graphviz. Graphviz is available for a
number of different platforms:
@example
output data. Delete everything from the beginning of the file
up to but not including the first occurrence of @code{digraph}.
-Also, delete the final liypond message about successs from the end
+Also, delete the final lilypond message about success from the end
of the file.
@item Process the logfile with @code{dot}
short, single-issue regression tests are preferred to a single, long,
multiple-issue regression test.
+If the change in the output is small or easy to overlook, use bigger
+staff size -- 40 or more (up to 100 in extreme cases). Size 30 means
+"pay extra attention to details in general".
+
Use existing regression tests as templates to demonstrate the type of
header information that should be included in a regression test.
and sent the music events to the appropriate engravers and/or
performers.
+See a short example discussing iterators and their duties in
+@ref{Articulations on EventChord}.
+
@node Engraver tutorial
@section Engraver tutorial
during line breaking, for example, when we want to estimate the Y-extent
of a spanner broken at given starting and ending columns.
-If the pure function you're writing takes more than three arguments
-(say, for example, a chained offset callback), this is not a problem:
-just make sure that the grob is the first argument and that start and
-end are the last two arguments.
-
@node How purity is defined and stored
@subsection How purity is defined and stored
* Spacing algorithms::
* Info from Han-Wen email::
* Music functions and GUILE debugging::
+* Articulations on EventChord::
@end menu
@node Spacing algorithms
A C(++) object that is encapsulated so it can be used as a Scheme
object. See GUILE info, "19.3 Defining New Types (Smobs)"
-@@subheading When is each C++ class constructed and used
+@subheading When is each C++ class constructed and used?
@itemize
@file{parser.yy}, run_music_function(). The function is called directly from
C++, without going through the GUILE evaluator, so I think that is why
there is no debugger trap.
+
+@node Articulations on EventChord
+@subsection Articulations on EventChord
+
+From David Kastrup's email
+@uref{http://lists.gnu.org/archive/html/lilypond-devel/2012-02/msg00189.html}:
+
+LilyPond's typesetting does not act on music expressions and music
+events. It acts exclusively on stream events. It is the act of
+iterators to convert a music expression into a sequence of stream events
+played in time order.
+
+The EventChord iterator is pretty simple: it just takes its "elements"
+field when its time comes up, turns every member into a StreamEvent and
+plays that through the typesetting process. The parser currently
+appends all postevents belonging to a chord at the end of "elements",
+and thus they get played at the same point of time as the elements of
+the chord. Due to this design, you can add per-chord articulations or
+postevents or even assemble chords with a common stem by using parallel
+music providing additional notes/events: the typesetter does not see a
+chord structure or postevents belonging to a chord, it just sees a
+number of events occuring at the same point of time in a Voice context.
+
+So all one needs to do is let the EventChord iterator play articulations
+after elements, and then adding to articulations in EventChord is
+equivalent to adding them to elements (except in cases where the order
+of events matters).
projects / lilypond.git / blobdiff