f:empty-length — Returns a map that represents an empty length.

Defined in:
Used in:
modules/units.xsl, modules/objects.xsl
Used by:


f:empty-length() as map(*)


Lengths are compound objects. Lengths consist of a magnitude (a number) and a unit: 3 inches, for example, or 11.9 barleycorns2 in the case of absolute lengths. For relative lengths, the unit is something relative like percent.

These are represented as maps internally and f:empty-length() returns a length with no magnitude or units.


Yes, that’s a real unit. It’s equal to ⅓ of an inch. I’ll leave it to Wikipedia to explain the details. Just looking at the chart of imperial units makes me want to add them all!

A graph showing the derivations of English imperial measurements: 12 inches to the foot, 3 feet to the yard, etc.

English imperial lengths

Image credit: 42CrMo4, Christoph Päper