2.1.3 Working on text files

LilyPond input files are treated like files in most programming languages: they are case sensitive, white-space insensitive, expressions are formed with curly braces { }, and comments are denoted with % or %{ .. %}.

If the previous sentence sounds like nonsense, don't worry! We'll explain what all these terms mean:

• Case sensitive: it matters whether you enter a letter in lower case (i.e. a, b, s, t) or upper case (i.e. A, B, S, T). Notes are lower case: { c d e } is valid input; { C D E } will produce an error message.
• Whitespace insensitive: it does not matter how many spaces (or new lines) you add. { c d e } means the same thing as { c d e } and

                 {
       c                        d
         e }
  

  Of course, the previous example is hard to read. A good rule of thumb is to indent code blocks with either a tab or two spaces:

       {
         c d e
       }
  

• Expressions: Every piece of LilyPond input needs to have { curly braces } placed around the input. These braces tell LilyPond that the input is a single music expression, just like parenthesis `()' in mathematics. The braces should be surrounded by a space unless they are at the beginning or end of a line to avoid ambiguities.

  A function (such as \relative { } ) also counts as a single music expression.

• Comments: A comment is a remark for the human reader of the music input; it is ignored while parsing, so it has no effect on the printed output. There are two types of comments. The percent symbol `%' introduces a line comment; anything after `%' on that line is ignored. A block comment marks a whole section of music input as a comment. Anything that is enclosed in %{ and %} is ignored. The following fragment shows possible uses for comments

       % notes for twinkle twinkle follow
         c4 c g' g a a g2
       
       %{
           This line, and the notes below
           are ignored, since they are in a
           block comment.
       
           g g f f e e d d c2
       %}
  

There are more tips for constructing input files in Suggestions for writing LilyPond files.

Other languages: French.