Unit
Statement
Identifies a unit of measure.
Syntax
Usual construct
[ @SI ] Unit unit_names [ = expression ]
Interval-scale construct
[ @SI ] Unit unit_names ( parameter In unit ) = expression
Parts
@SI
- Optional indication of an SI (metric) unit.
unit_names
- Mandatory one or more names with spaces between each.
All names identify the same unit.
Unit name
[ number ] { name | name + suffix | prefix - name }
name
- Mandatory basic name for a unit of measure.
number
- One of the integer literals that follow:
1
–name
is irregular and grammatically singular. For example, «1 foot
».2
–name
is irregular and grammatically plural. For example, «2 feet
».0
–name
is grammatically singular for zero and one. This occurs in some languages, for example, French. You can use0
(and no others) withsuffix
orprefix
.
suffix
- Mandatory after
+
. Identifies the regular plural suffix forname
. For example, «metre+s
» or «inch+es
». prefix
- Mandatory before a hyphen (
-
). Identifies the regular plural prefix forname
. This occurs in some languages, most frequently in Africa. For example, in Swahili, «ma-debe
».
expression
- A conversion factor.
- Optional in the usual construct.
- Mandatory in the interval-scale construct.
parameter
- Mandatory in the interval-scale construct.
You use it with
expression
for a unit with an interval scale, for example, a unit of temperature. unit
- A different unit that is related to this unit.
Instructions
TODO
Examples
@SI Unit meter+s metre+s m
Unit light_year+s ly = 9.4605284 petameters
Unit Kelvin K
Unit Celsius 1 degree_C 2 degrees_C (k In Kelvin) = k + 273.15