Scalar Units

This section is about scalar units. Unit vectors are discussed as part of the matrix type.

Base units

A unit of measurement is build from base units by multiplication and division. A base unit has a name and a symbol. It is defined as follows

defunit name symbol_string;

For example

defunit metre "m";

Derived units are build from base units.

defunit name symbol_string = unit_expression;

For example

defunit mile "mi" = 1609.344 * metre;

defunit foot "ft" = 0.3048 * metre;

defunit newton "N" = kilo:gram*metre/second^2;

It is good practice to define units for dimensionless quantities. For example the number of cars could be given unit car:

defunit car "car" = 1;

Note that this differs from a base unit. A base unit cannot be converted, while this unit can.

A conversion between units can be defined with keyword defconv. The following

defconv mile2foot :: foot/mile;

make mile2foot the conversion factor 5280.00ft/mi.

More on conversions in the matrix type sections.