Documentation

Default set of definitions that come predefined.

Create a Quantity by parsing a string. Uses an UndefinedUnitError for undefined units. Handles arithmetic expressions as well.

>>> fromString "25 m/s" Right 25.0 meter / second >>> fromString "fakeunit" Left (UndefinedUnitError "fakeunit") >>> fromString "ft + 12in" Right 2.0 foot 

This function also supports unit conversions, by placing "=>" in between two valid expressions. This behavior is undefined (and returns a ScalingFactorError) if the quantity to be converted to has a magnitude.

>>> fromString "min => s" Right 60.0 second >>> fromString "2 ft + 6 in => ft" Right 2.5 foot >>> fromString "m => 3 ft" Left (ScalingFactorError 3.0 foot) 

Make sure not to use dimensional quantities in exponents.

>>> fromString "m ** 2" Right 1.0 meter ** 2 >>> fromString "m ** (2s)" Left (ParserError "Used non-dimensionless exponent in ( Right 1.0 meter ) ** ( Right 2.0 second )") 

Create quantities with custom definitions.

>>> let myDefString = defaultDefString ++ "\nmy_unit = 100 s" >>> let (Right d) = readDefinitions myDefString >>> let myFromString = fromString' d >>> myFromString "25 my_unit" Right 25.0 my_unit 

Parse units from a string. Equivalent to fmap units . fromString

>>> unitsFromString "N * s" Right newton second