# Key/Value pairs

Many directives take additional attributes in the form of key/value pairs.

For example,

label=Chorus
label="Chorus"

Either will assign the value "Chorus" to attribute label.

Using quotes is optional unless the value contains spaces.

label="Verse 1"

# To be or not to be

Often an attribute takes a logical value to enable or disable something.

diagram=no

The attribute is considered enabled when the value is any of:

1
on
true

To disable, use:

0
off
false
null
no
none

In most cases, an empty value is also considered false, and everything else not enumerated above is considered true. But best is to stick to the values shown above.

# Numeric values

If an attribute requires a numeric value, this can be an optionally signed number, optionally followed by a fraction.

1
-42
3.14

Degenerate cases like .1 and 2. are not recognized.

Depending on the context a numeric value can have a unit, e.g. 60% or 1.4em.

Unit	Value
%	Percentage, 60% is the same as 0.6
em	Fraction of the current font size
ex	Fraction of half the current font size
pt	Typographical point, 1/72 inch
px	Pixel, 1/96 inch, 0.75pt
in	Inch, 2.54cm, 72pt, 96px
cm	Centimeter, 10mm
mm	Millimeter

Default for dimensions is points. For example, the following are equivalent:

width=515
width=515pt