Units

Units in Formever are measures of something – Length, Area, Volume, Counts etc. 

For sake of discussion and this documentation Units can be sub-categorized into Dimensional  units and Dimensionless units. 

Dimensional units are measures of:

• Length
• Volume
• Weight
• Energy
• Temperature
• Area
• Duration

Dimensionless units are basically counts. Most often Dimensionless units are related to packaging things. For example, dozen eggs, ream of paper, coil of sheet metal.

Conversion between similar types of units (e.g. length) are straight-forward because the conversion rate is always fixed. For example, converting between inches and millimeters has a fixed rate of 1" = 2.54mm. Contrast this with conversion between currencies which have fluctuating exchange rates. 

Formever works on the concept of ‘dimensionality’. All of the categories above are dimensionalities e.g. length, weight, duration etc. Dimensionalities cannot be mixed. For example you cannot add a length quantity to a volume quantity. This makes no sense and Formever doesn’t allow it. This strict enforcement of dimensionality ensures that calculation results makes sense.

Quantities of the same dimensionalities can always be added or subtracted.

Dimensionless quantities can multiply or divide any quantity of any dimensionality. The only other quantities that can be multiplied or divided are rate units. For example a rate of currency/duration can be multiplied by a duration to return a currency result. Another example is that a currency quantity could be divided by a currency/weight rate to return a quantity of weight dimensionality.

In a general calculus of dimensionality it should be possible to do calculations such as length x length giving area. Or volume divided by length is area. This is an aspirational dream for future Formever. At present Formever only supports basic dimensionality arithmetic.