examples this works well, but for more complex examples, especially
when additional commands are used, the implicit creation of contexts
can give surprising results, maybe creating extra unwanted staves.
-When entering more than a few lines of music it is advisable to
-always create staves and voices explicitly, see
+The way to create contexts explicitly is explained in
@ref{Contexts and engravers}.
+@warning{When entering more than a few lines of music it is
+advisable to always create staves and voices explicitly.}
+
For now, though, let us return to the first example and examine the
@code{\score} command, leaving the others to default.
@end quotation
@noindent
-You may find it useful to review
+To understand what is meant by a music expression and a compound
+music expression you may find it useful to review
@ref{Music expressions explained}. In that section, we saw how to
build big music expressions from small pieces -- we started from
notes, then chords, etc. Now we're going to start from a big
}
@end lilypond
+Now let's look at three different ways to notate the same passage
+of polyphonic music, each of which is advantageous in different
+circumstances, using the example from the previous section.
+
An expression that appears directly inside a @code{<< >>} belongs
to the main voice (but, note, @strong{not} in a @code{<< \\ >>}
construct). This is useful when extra voices appear while the
-main voice is playing. Here is a more correct rendition of the
-example from the previous section. The red diamond-shaped notes
+main voice is playing. Here is a more correct rendition of our
+example. The red diamond-shaped notes
demonstrate that the main melody is now in a single voice context,
permitting a phrasing slur to be drawn over them.
More deeply nested polyphony constructs are possible, and if a
voice appears only briefly this might be a more natural way to
-typeset the music.
+typeset the music:
@lilypond[quote,ragged-right,verbatim]
\new Staff \relative c' {
>>
@end lilypond
+@subsubheading Note columns
+
@cindex note column
@cindex shift commands
@funindex \shiftOff
Here is a example of the first line of a hymn with four
verses, set for SATB. In this case the words for all four
-parts are the same.
+parts are the same. Note how we use variables to separate the
+music notation and words from the staff structure. See too
+how a variable, which we have chosen to call @q{TimeKey}, is used
+to hold several commands for use within the two staves. In other
+examples this is often called @q{global}.
@lilypond[quote,verbatim]
TimeKey = { \time 4/4 \partial 4 \key c \major}
the single top-level @code{Score} context is introduced
with @code{\score}.
+You have seen many practical examples which created new
+@code{Staff} and @code{Voice} contexts in earlier sections, but
+to remind you how these commands are used in practice, here's an
+annotated real-music example:
+
+@lilypond[quote,verbatim,ragged-right]
+\score { % start single compound music expression
+ << % start of simultaneous staves section
+ \time 2/4
+ \new Staff { % create RH staff
+ \key g \minor
+ \clef "treble"
+ \new Voice { % create voice for RH notes
+ \relative c'' { % start of RH notes
+ d4 ees16 c8. |
+ d4 ees16 c8. |
+ } % end of RH notes
+ } % end of RH voice
+ } % end of RH staff
+ \new Staff << % create LH staff; needs two simultaneous voices
+ \key g \minor
+ \clef "bass"
+ \new Voice { % create LH voice one
+ \voiceOne
+ \relative g { % start of LH voice one notes
+ g8 <bes d> ees, <g c> |
+ g8 <bes d> ees, <g c> |
+ } % end of LH voice one notes
+ } % end of first LH voice
+ \new Voice { % create LH voice two
+ \voiceTwo
+ \relative g { % start of LH voice two notes
+ g4 ees |
+ g4 ees |
+ } % end of LH voice two notes
+ } % end of LH voice two
+ >> % end of LH staff
+ >> % end of simultaneous staves section
+} % end of single compound music expression
+@end lilypond
+
+(Note how all the statements which open a block with either a
+curly bracket, @code{@{}, or double angle brackets, @code{<<},
+are indented by two further spaces, and the corresponding
+closing bracket is indented by exactly the same amount. While
+this is not required, following this practice will greatly
+reduce the number of @q{unmatched bracket} errors, and is
+strongly recommended. It enables the structure of the music to
+be seen at a glance, and any unmatched brackets will be obvious.
+Note too how the LH staff is created using double angle brackets
+because it requires two voices for its music, whereas the RH staff
+is created with a single music expression surrounded by curly
+brackets because it requires only one voice.)
+
@cindex contexts, naming
@cindex naming contexts
>> % end ChoirStaff
\new PianoStaff <<
- \set PianoStaff.instrumentName = "Piano "
+ \set PianoStaff.instrumentName = "Piano"
\new Staff = "upper" \upper
\new Staff = "lower" \lower
>>
>> % end ChoirStaff
\new PianoStaff <<
- \set PianoStaff.instrumentName = "Piano "
+ \set PianoStaff.instrumentName = "Piano"
\new Staff = "upper" \upper
\new Staff = "lower" \lower
>>
Next we need to add a staff for the pedal organ.
This goes underneath the PianoStaff, but it must
be simultaneous with it, so we need angle brackets
-round the two. Missing these out would generate
+around the two. Missing these out would generate
an error in the log file. It's a common mistake
which you'll make sooner or later! Try copying
the final example at the end of this section,
g4 g f ees | d2 c2 |
}
ManualOneVoiceTwoMusic = \relative c' {
- ees16 d ees8~ ees16 f ees s c8 d~ d c~ |
+ ees16 d ees8~ ees16 f ees d c8 d~ d c~ |
c c4 b8 c8. g16 c b c d |
}
ManualTwoMusic = \relative c' {
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