Composite Unit Measurements

A collection of specialized parsers designed for handling composite measurement strings.

Harshal V. Ladhe, M.Sc. Computer Science.

Introduction

The composite_unit_measurements gem offers versatile parsers for efficiently parsing composite measurement strings. Leveraging the power of the unit_measurements gem, it enables smooth handling of composite measurements in various units.

Minimum Requirements

Ruby 3.2.2+ (Download Ruby)

Installation

To use composite_unit_measurements in your Rails application, add the following line to your Gemfile:

gem "composite_unit_measurements"

And then execute:

$ bundle install

Or otherwise simply install it yourself as:

$ gem install composite_unit_measurements

Usage

Each packaged parser includes the .parse method to parse composite measurements. You can use an appropriate parser to these measurements and the final result of is returned in the leftmost unit of your measurement.

The result of each parser method returns an instance of measurement on which we can perform any functionality offered by unit_measurements.

This gem internally uses unit_measurements to perform conversions and arithmetic operations. You can build supported composite measurements using any unit alias.

Examples

Parsing length measurements:

CompositeUnitMeasurements::Length.parse("5 km 500 m") #=> 5.5 km

Parsing weight measurements:

CompositeUnitMeasurements::Weight.parse("4 kg 500 g") # 4.5 kg

Parsing time measurements:

CompositeUnitMeasurements::Time.parse("3 h 45 min") #=> 3.75 hr

Parsing volume measurements:

CompositeUnitMeasurements::Volume.parse("2 l 250 ml") #=> 2.25 l

Support for numeric types

Each parser can handle various numeric types, including scientific notation, rational numbers, and complex numbers.

CompositeUnitMeasurements::Length.parse("1+2i ft 12 in")    #=> 2.0+2.0i ft
CompositeUnitMeasurements::Length.parse("1.5 ft 12e2 in")   #=> 101.5 ft
CompositeUnitMeasurements::Length.parse("1 1/2 ft 1+2i in") #=> 1.5833333333333333+0.16666666666666669i ft
CompositeUnitMeasurements::Length.parse("2 ft 1+2i in")     #=> 2.0833333333333335+0.16666666666666669i ft
CompositeUnitMeasurements::Length.parse("1e-2 ft 1+2i in")  #=> 0.09333333333333334+0.16666666666666669i ft

Packaged parsers & supported composite measurements

The composite_unit_measurements gem supports parsing various composite measurements, including:

1. CompositeUnitMeasurements::Length

metre-centimetre (6 m 50 cm)
kilometre-metre (5 km 500 m)
foot-inch (5 ft 6 in)

2. CompositeUnitMeasurements::Weight

kilogramme-gramme (4 kg 500 g)
pound-ounce (8 lb 12 oz)
stone-pound (2 st 6 lb)

3. CompositeUnitMeasurements::Time

hour-minute (3 h 45 min)
hour-minute-second-microsecond (12:60,3600:360000000)

4. CompositeUnitMeasurements::Volume

litre-millilitre (2 l 250 ml)

Specifing parsers

By default, composite_unit_measurements includes all packaged parsers automatically when required in your application. However, you can opt to use specific parsers as needed:

require "composite_unit_measurements/base"

require "composite_unit_measurements/length"
require "composite_unit_measurements/weight"

Contributing

Contributions to this project are welcomed! To contribute:

Fork this repository
Create a new branch (git checkout -b my-new-feature)
Commit your changes (git commit -am "Add some feature")
Push the changes to your branch (git push origin my-new-feature)
Create new Pull Request