## Example ##

unit = Unit.km                                               #=> #<Quantify::Unit::SI:0xb75c9718 ... >
unit.name                                                    #=> 'kilometre'
unit.symbol                                                  #=> 'kg'
unit.dimensions                                              #=> #<Quantify::Dimensions:0xb75c4254 .. >
unit.measures                                                #=> 'length'
unit.alternatives :name                                      #=> ['metre', 'megametre', 'gigametre', 'terametre', 'angstrom',
                                                             #    'astronomical unit', 'baromil', 'chain', 'dram', 'ell', 'fathom',
                                                             #    'fermi', 'foot us survey', 'foot', 'furlong', 'hand', 'inch',
                                                             #    'nautical league', 'statute league', 'light year', 'line',
                                                             #    'link', 'yard']
other_unit = Unit.hour
other_unit.name                                              #=> 'hour'
other_unit.symbol                                            #=> 'h'
other_unit.measures                                          #=> 'time'
other_unit.alternatives :symbol                              #=> [ 's', 'ks', 'Ms', 'Gs', 'Ts', 'd', 'min' ]

another_unit = unit / other_unit                             #=> #<Quantify::Unit::Compound:0xb74af323 ... >
another_unit.name                                            #=> 'kilometer per hour'
another_unit.symbol                                          #=> 'km h^-1'
another_unit.measures                                        #=> 'velocity'

last_unit = Unit.m
last.unit.measures                                           #=> 'length'
square = last_unit ** 2                                      #=> #<Quantify::Unit::Compound:0xb446f12f ... >
square.symbol                                                #=> 'm^2'
square.measures                                              #=> 'area'

----

# Define quantity - method 1
quantity = Quantity.new(1234.5678, :lb)                      #=> #<Quantify::Quantity:0xjk39d570 ... >
quantity.value                                               #=> 1234.5678
quantity.unit                                                #=> #<Quantify::Unit::NonSI:0xb182124 ... >
quantity.unit.symbol                                         #=> 'lb'

# Define quantity - method 2
string = quantity.to_s                                       #=> "1234.5678 lb"
quantity = Quantity.parse(string)                            #=> #<Quantify::Quantity:0xj982b4f9 ... >
quantity.to_s                                                #=> "1234.5678 lb"

# Define quantity - method 3
quantity = 1234.5678.lb                                      #=> #<Quantify::Quantity:02387f7340 ... >
quantity.to_s                                                #=> "1234.5678 lb"

# Multiply by scalar
new_quantity = quantity * 4                                  #=> #<Quantify::Quantity:87b37f720 ... >
new_quantity.to_s                                            #=> "4938.2712 lb"

# Convert unit
converted_quantity = new_quantity.to_kg                      #=> #<Quantify::Quantity:0b8787a688 ... >
converted_quantity.to_s                                      #=> "2239.96213731074 kg"

----

# One line conversion of a quantity to a new unit
# 5000 litres into US petroleum barrels

5000.L.to_bbl.value                                          #=> 31.4490528488754

----

# Complex example

# Define energy units
kW = Unit.kW                                                 #=> #<Quantify::Unit::SI:0xb7586620 ... >
kW.name                                                      #=> 'kilowatt'
kW.measures                                                  #=> 'power'

h = Unit.h                                                   #=> #<Quantify::Unit::NonSI:0xb7582994 ... >
h.symbol                                                     #=> 'h'
h.measures                                                   #=> 'time'

# Create compound unit for energy
kWh = kW / h                                                 #=> #<Quantify::Unit::Compound:0xb756b0b4 ... >
kWh.name                                                     #=> 'kilowatt hour'
kWh.measures                                                 #=> 'energy'
kWh.alternatives :symbol                                     #=> ['J', 'kJ', 'MJ', 'GJ', 'TJ', 'BTU', 'cal', 'CHU',
                                                             #    'dyn cm', 'eV', 'erg', 'Eh']
kWh.alternative :name                                        #=> ['joule', 'kilojoule', 'megajoule', 'gigajoule',
                                                             #    'terajoule', 'british thermal unit', 'calorie',
                                                             #    'celsius heat unit', 'dyne centimetre', 'electron volt',
                                                             #    'erg', 'hartree']

# Create mass unit
kg = Unit.kg                                                 #=> #<Quantify::Unit::SI:0xb758b594 ... >

# Create emission factor compound unit
kg_per_kWh = kg / kWh                                        #=> #<Quantify::Unit::Compound:0xb746f093 ... >
kg_per_kWh.symbol                                            #=> "kg_kW^-1_h^-1
kg_per_kWh.name                                              #=> 'kilogram per kilowatt hour'

# Create emission factor quantity
emission_factor = Quantity.new(0.54, kg_per_kWh)             #=> #<Quantify::Quantity:0xb75cd570 ... >
emission_factor.to_s                                         #=> "0.54 kg kW^-1 h^-1"

# Create consumption quantity
consumption = Quantity.new(9885.5, kWh)                      #=> #<Quantify::Quantity:0xb7j4k3570 ... >
consumption.to_s                                             #=> "9885.5 kWh"

# Calculate emissions
emissions = consumption * emission_factor                    #=> #<Quantify::Quantity:0xb456g2s70 ... >
emissions.to_s                                               #=> "5338.17 kg"