LilyPond Learning Manual: 4.6.2 Using variables for tweaks

### 4.6.2 Using variables for tweaks

Override commands are often long and tedious to type, and they have to be absolutely correct. If the same overrides are to be used many times it may be worth defining variables to hold them.

Suppose we wish to emphasize certain words in lyrics by printing them in bold italics. The `\italic` and `\bold` commands only work within lyrics if they are embedded, together with the word or words to be modified, within a `\markup` block, which makes them tedious to enter. The need to embed the words themselves prevents their use in simple variables. As an alternative can we use `\override` and `\revert` commands?

>     \override Lyrics . LyricText #'font-shape = #'italic
>     \override Lyrics . LyricText #'font-series = #'bold

>     \revert Lyrics . LyricText #'font-shape
>     \revert Lyrics . LyricText #'font-series

These would also be extremely tedious to enter if there were many words requiring emphasis. But we can define these as two variables and use those to bracket the words to be emphasized. Another advantage of using variables for these overrides is that the spaces around the dot are not necessary, since they are not being interpreted in `\lyricmode` directly. Here’s an example of this, although in practice we would choose shorter names for the variables to make them quicker to type:

>     emphasize = {
>       \override Lyrics.LyricText #'font-shape = #'italic
>       \override Lyrics.LyricText #'font-series = #'bold
>     }

>     normal = {
>       \revert Lyrics.LyricText #'font-shape
>       \revert Lyrics.LyricText #'font-series
>     }

>     global = { \key c \major \time 4/4 \partial 4 }

>     SopranoMusic = \relative c' { c4 | e4. e8 g4 g    | a4   a   g  }
>     AltoMusic    = \relative c' { c4 | c4. c8 e4 e    | f4   f   e  }
>     TenorMusic   = \relative c  { e4 | g4. g8 c4.  b8 | a8 b c d e4 }
>     BassMusic    = \relative c  { c4 | c4. c8 c4 c    | f8 g a b c4 }

>     VerseOne = \lyrics {
>       E -- | ter -- nal \emphasize Fa -- ther, | \normal strong to save,
>     }

>     VerseTwo = \lyricmode {
>       O | \emphasize Christ, \normal whose voice the | wa -- ters heard,
>     }

>     VerseThree = \lyricmode {
>       O | \emphasize Ho -- ly Spi -- rit, | \normal who didst brood
>     }

>     VerseFour = \lyricmode {
>       O | \emphasize Tri -- ni -- ty \normal of | love and pow'r
>     }

>     \score {
>       \new ChoirStaff <<
>         \new Staff <<
>           \clef "treble"
>           \new Voice = "Soprano"  { \voiceOne \global \SopranoMusic }
>           \new Voice = "Alto" { \voiceTwo \AltoMusic }
>           \new Lyrics \lyricsto "Soprano" { \VerseOne }
>           \new Lyrics \lyricsto "Soprano" { \VerseTwo }
>           \new Lyrics \lyricsto "Soprano" { \VerseThree }
>           \new Lyrics \lyricsto "Soprano" { \VerseFour }
>         >>
>         \new Staff <<
>           \clef "bass"
>           \new Voice = "Tenor" { \voiceOne \TenorMusic }
>           \new Voice = "Bass"  { \voiceTwo \BassMusic }
>         >>
>       >>
>     }

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