Base Unit Definition

A unit definition starts with keyword defunit. It can define a base unit, a derived unit, or a unit vector.

A base unit definition requires a name and a string to be used in output.

defunit metre "m";

A derived unit requires an additonal unit expression. This is an expression with operators *, / and ^ on base units or other derived units.

defunit knot "kn" = 0.51444444*metre/second;

A unit vector is defined for an index set by specifying a unit for each index key. An exclamation mark seperates the index set name from the unit vector name.

defunit Foo!unit = {foo: metre, bar: knot, ...};

Unit vectors are used in matrix types.