olbrich/ruby-units

# frozen_string_literal: true

# length units

RubyUnits::Unit.define("inch") do |inch|
  inch.definition = RubyUnits::Unit.new("254/10000 meter")
  inch.aliases    = %w[in inch inches "]
end

RubyUnits::Unit.define("foot") do |foot|
  foot.definition = RubyUnits::Unit.new("12 inches")
  foot.aliases    = %w[ft foot feet ']
end

RubyUnits::Unit.define("survey-foot") do |sft|
  sft.definition = RubyUnits::Unit.new("1200/3937 meter")
  sft.aliases    = %w[sft sfoot sfeet]
end

RubyUnits::Unit.define("yard") do |yard|
  yard.definition = RubyUnits::Unit.new("3 ft")
  yard.aliases    = %w[yd yard yards]
end

RubyUnits::Unit.define("mile") do |mile|
  mile.definition = RubyUnits::Unit.new("5280 ft")
  mile.aliases    = %w[mi mile miles]
end

RubyUnits::Unit.define("naut-mile") do |naut|
  naut.definition = RubyUnits::Unit.new("1852 m")
  naut.aliases    = %w[nmi NM]
  # Don't use the 'M' abbreviation here since it conflicts with 'Molar'
end

# on land
RubyUnits::Unit.define("league") do |league|
  league.definition = RubyUnits::Unit.new("3 miles")
  league.aliases    = %w[league leagues]
end

# at sea
RubyUnits::Unit.define("naut-league") do |naut_league|
  naut_league.definition = RubyUnits::Unit.new("3 nmi")
  naut_league.aliases    = %w[nleague nleagues]
end

RubyUnits::Unit.define("furlong") do |furlong|
  furlong.definition = RubyUnits::Unit.new("1/8 mile")
  furlong.aliases    = %w[fur furlong furlongs]
end

RubyUnits::Unit.define("rod") do |rod|
  rod.definition  = RubyUnits::Unit.new("33/2 feet")
  rod.aliases     = %w[rd rod rods]
end

RubyUnits::Unit.define("fathom") do |fathom|
  fathom.definition = RubyUnits::Unit.new("6 ft")
  fathom.aliases    = %w[fathom fathoms]
end

RubyUnits::Unit.define("mil") do |mil|
  mil.definition = RubyUnits::Unit.new("1/1000 inch")
  mil.aliases    = %w[mil mils]
end

RubyUnits::Unit.define("angstrom") do |ang|
  ang.definition = RubyUnits::Unit.new("1/10 nm")
  ang.aliases    = %w[ang angstrom angstroms]
end

# typesetting

RubyUnits::Unit.define("pica") do |pica|
  pica.definition = RubyUnits::Unit.new("1/72 ft")
  pica.aliases    = %w[pica picas]
  # Don't use 'P' as an abbreviation since it conflicts with 'Poise'
  # Don't use 'pc' as an abbreviation since it conflicts with 'parsec'
end

RubyUnits::Unit.define("point") do |point|
  point.definition = RubyUnits::Unit.new("1/12 pica")
  point.aliases    = %w[point points]
end

RubyUnits::Unit.define("dot") do |dot|
  dot.definition  = RubyUnits::Unit.new("1 each")
  dot.aliases     = %w[dot dots]
  dot.kind        = :counting
end

RubyUnits::Unit.define("pixel") do |pixel|
  pixel.definition  = RubyUnits::Unit.new("1 each")
  pixel.aliases     = %w[px pixel pixels]
  pixel.kind        = :counting
end

RubyUnits::Unit.define("ppi") do |ppi|
  ppi.definition  = RubyUnits::Unit.new("1 pixel/inch")
end

RubyUnits::Unit.define("dpi") do |dpi|
  dpi.definition  = RubyUnits::Unit.new("1 dot/inch")
end

# Mass

avagadro_constant = RubyUnits::Unit.new("6.02214129e23 1/mol")

RubyUnits::Unit.define("AMU") do |amu|
  amu.definition = RubyUnits::Unit.new("0.012 kg/mol") / (12 * avagadro_constant)
  amu.aliases    = %w[u AMU amu]
end

RubyUnits::Unit.define("dalton") do |dalton|
  dalton.definition = RubyUnits::Unit.new("1 amu")
  dalton.aliases    = %w[Da dalton daltons]
end

RubyUnits::Unit.define("metric-ton") do |mton|
  mton.definition = RubyUnits::Unit.new("1000 kg")
  mton.aliases    = %w[tonne]
end

# defined as a rational number to preserve accuracy and minimize round-off errors during
# calculations
RubyUnits::Unit.define("pound") do |pound|
  pound.definition = RubyUnits::Unit.new(Rational(45_359_237, 1e8), "kg")
  pound.aliases    = %w[lbs lb lbm pound-mass pound pounds #]
end

RubyUnits::Unit.define("ounce") do |ounce|
  ounce.definition = RubyUnits::Unit.new("1/16 lbs")
  ounce.aliases    = %w[oz ounce ounces]
end

RubyUnits::Unit.define("gram") do |gram|
  gram.definition = RubyUnits::Unit.new("1/1000 kg")
  gram.aliases    = %w[g gram grams gramme grammes]
end

RubyUnits::Unit.define("short-ton") do |ton|
  ton.definition = RubyUnits::Unit.new("2000 lbs")
  ton.aliases    = %w[tn ton tons short-tons]
end

RubyUnits::Unit.define("carat") do |carat|
  carat.definition = RubyUnits::Unit.new("1/5000 kg")
  carat.aliases    = %w[ct carat carats]
end

RubyUnits::Unit.define("stone") do |stone|
  stone.definition = RubyUnits::Unit.new("14 lbs")
  stone.aliases    = %w[st stone]
end

# time

RubyUnits::Unit.define("minute") do |min|
  min.definition = RubyUnits::Unit.new("60 seconds")
  min.aliases    = %w[min minute minutes]
end

RubyUnits::Unit.define("hour") do |hour|
  hour.definition = RubyUnits::Unit.new("60 minutes")
  hour.aliases    = %w[h hr hrs hour hours]
end

RubyUnits::Unit.define("day") do |day|
  day.definition  = RubyUnits::Unit.new("24 hours")
  day.aliases     = %w[d day days]
end

RubyUnits::Unit.define("week") do |week|
  week.definition   = RubyUnits::Unit.new("7 days")
  week.aliases      = %w[wk week weeks]
end

RubyUnits::Unit.define("fortnight") do |fortnight|
  fortnight.definition  = RubyUnits::Unit.new("2 weeks")
  fortnight.aliases     = %w[fortnight fortnights]
end

RubyUnits::Unit.define("year") do |year|
  year.definition = RubyUnits::Unit.new("31556926 seconds") # works out to 365.24219907407405 days
  year.aliases    = %w[y yr year years annum]
end

RubyUnits::Unit.define("decade") do |decade|
  decade.definition = RubyUnits::Unit.new("10 years")
  decade.aliases    = %w[decade decades]
end

RubyUnits::Unit.define("century") do |century|
  century.definition  = RubyUnits::Unit.new("100 years")
  century.aliases     = %w[century centuries]
end

# area

RubyUnits::Unit.define("hectare") do |hectare|
  hectare.definition = RubyUnits::Unit.new("10000 m^2")
end

RubyUnits::Unit.define("acre") do |acre|
  acre.definition = (RubyUnits::Unit.new("1 mi")**2) / 640
  acre.aliases    = %w[acre acres]
end

RubyUnits::Unit.define("sqft") do |sqft|
  sqft.definition = RubyUnits::Unit.new("1 ft^2")
end

RubyUnits::Unit.define("sqin") do |sqin|
  sqin.definition = RubyUnits::Unit.new("1 in^2")
end

# volume

RubyUnits::Unit.define("liter") do |liter|
  liter.definition = RubyUnits::Unit.new("1/1000 m^3")
  liter.aliases    = %w[l L liter liters litre litres]
end

RubyUnits::Unit.define("gallon") do |gallon|
  gallon.definition = RubyUnits::Unit.new("231 in^3")
  gallon.aliases    = %w[gal gallon gallons]
end

RubyUnits::Unit.define("quart") do |quart|
  quart.definition  = RubyUnits::Unit.new("1/4 gal")
  quart.aliases     = %w[qt quart quarts]
end

RubyUnits::Unit.define("pint") do |pint|
  pint.definition = RubyUnits::Unit.new("1/8 gal")
  pint.aliases    = %w[pt pint pints]
end

RubyUnits::Unit.define("cup") do |cup|
  cup.definition = RubyUnits::Unit.new("1/16 gal")
  cup.aliases    = %w[cu cup cups]
end

RubyUnits::Unit.define("fluid-ounce") do |floz|
  floz.definition = RubyUnits::Unit.new("1/128 gal")
  floz.aliases    = %w[floz fluid-ounce fluid-ounces]
end

RubyUnits::Unit.define("tablespoon") do |tbsp|
  tbsp.definition = RubyUnits::Unit.new("1/2 floz")
  tbsp.aliases    = %w[tbs tbsp tablespoon tablespoons]
end

RubyUnits::Unit.define("teaspoon") do |tsp|
  tsp.definition = RubyUnits::Unit.new("1/3 tablespoon")
  tsp.aliases    = %w[tsp teaspoon teaspoons]
end

##
# The board-foot is a specialized unit of measure for the volume of lumber in
# the United States and Canada. It is the volume of a one-foot length of a board
# one foot wide and one inch thick.
# http://en.wikipedia.org/wiki/Board_foot
RubyUnits::Unit.define("bdft") do |bdft|
  bdft.definition = RubyUnits::Unit.new("1/12 ft^3")
  bdft.aliases    = %w[fbm boardfoot boardfeet bf]
end

# volumetric flow

RubyUnits::Unit.define("cfm") do |cfm|
  cfm.definition = RubyUnits::Unit.new("1 ft^3/minute")
  cfm.aliases    = %w[cfm CFM CFPM]
end

# speed

RubyUnits::Unit.define("kph") do |kph|
  kph.definition  = RubyUnits::Unit.new("1 kilometer/hour")
end

RubyUnits::Unit.define("mph") do |mph|
  mph.definition  = RubyUnits::Unit.new("1 mile/hour")
end

RubyUnits::Unit.define("fps") do |fps|
  fps.definition  = RubyUnits::Unit.new("1 foot/second")
end

RubyUnits::Unit.define("knot") do |knot|
  knot.definition   = RubyUnits::Unit.new("1 nmi/hour")
  knot.aliases      = %w[kt kn kts knot knots]
end

RubyUnits::Unit.define("gee") do |gee|
  # approximated as a rational number to minimize round-off errors
  gee.definition    = RubyUnits::Unit.new(Rational(196_133, 20_000), "m/s^2") # equivalent to 9.80665 m/s^2
  gee.aliases       = %w[gee standard-gravitation]
end

# temperature differences

RubyUnits::Unit.define("newton") do |newton|
  newton.definition = RubyUnits::Unit.new("1 kg*m/s^2")
  newton.aliases    = %w[N newton newtons]
end

RubyUnits::Unit.define("dyne") do |dyne|
  dyne.definition = RubyUnits::Unit.new("1/100000 N")
  dyne.aliases    = %w[dyn dyne]
end

RubyUnits::Unit.define("pound-force") do |lbf|
  lbf.definition  = RubyUnits::Unit.new("1 lb") * RubyUnits::Unit.new("1 gee")
  lbf.aliases     = %w[lbf pound-force]
end

RubyUnits::Unit.define("poundal") do |poundal|
  poundal.definition  = RubyUnits::Unit.new("1 lb") * RubyUnits::Unit.new("1 ft/s^2")
  poundal.aliases     = %w[pdl poundal poundals]
end

temp_convert_factor = Rational(2_501_999_792_983_609, 4_503_599_627_370_496) # approximates 1/1.8

RubyUnits::Unit.define("celsius") do |celsius|
  celsius.definition  = RubyUnits::Unit.new("1 degK")
  celsius.aliases     = %w[degC celsius centigrade]
end

RubyUnits::Unit.define("fahrenheit") do |fahrenheit|
  fahrenheit.definition = RubyUnits::Unit.new(temp_convert_factor, "degK")
  fahrenheit.aliases    = %w[degF fahrenheit]
end

RubyUnits::Unit.define("rankine") do |rankine|
  rankine.definition  = RubyUnits::Unit.new("1 degF")
  rankine.aliases     = %w[degR rankine]
end

RubyUnits::Unit.define("tempC") do |temp_c|
  temp_c.definition  = RubyUnits::Unit.new("1 tempK")
end

RubyUnits::Unit.define("tempF") do |temp_f|
  temp_f.definition  = RubyUnits::Unit.new(temp_convert_factor, "tempK")
end

RubyUnits::Unit.define("tempR") do |temp_r|
  temp_r.definition  = RubyUnits::Unit.new("1 tempF")
end

# astronomy

speed_of_light = RubyUnits::Unit.new("299792458 m/s")

RubyUnits::Unit.define("light-second") do |ls|
  ls.definition = RubyUnits::Unit.new("1 s") * speed_of_light
  ls.aliases    = %w[ls lsec light-second]
end

RubyUnits::Unit.define("light-minute") do |lmin|
  lmin.definition = RubyUnits::Unit.new("1 min") * speed_of_light
  lmin.aliases    = %w[lmin light-minute]
end

RubyUnits::Unit.define("light-year") do |ly|
  ly.definition = RubyUnits::Unit.new("1 y") * speed_of_light
  ly.aliases    = %w[ly light-year]
end

RubyUnits::Unit.define("parsec") do |parsec|
  parsec.definition = RubyUnits::Unit.new("3.26163626 ly")
  parsec.aliases    = %w[pc parsec parsecs]
end

# once was '149597900000 m' but there appears to be a more accurate estimate according to wikipedia
# see http://en.wikipedia.org/wiki/Astronomical_unit
RubyUnits::Unit.define("AU") do |au|
  au.definition = RubyUnits::Unit.new("149597870700 m")
  au.aliases    = %w[AU astronomical-unit]
end

RubyUnits::Unit.define("redshift") do |red|
  red.definition = RubyUnits::Unit.new("1.302773e26 m")
  red.aliases    = %w[z red-shift]
end

# mass

RubyUnits::Unit.define("slug") do |slug|
  slug.definition = RubyUnits::Unit.new("1 lbf*s^2/ft")
  slug.aliases    = %w[slug slugs]
end

# pressure

RubyUnits::Unit.define("pascal") do |pascal|
  pascal.definition = RubyUnits::Unit.new("1 kg/m*s^2")
  pascal.aliases    = %w[Pa pascal pascals]
end

RubyUnits::Unit.define("bar") do |bar|
  bar.definition  = RubyUnits::Unit.new("100 kPa")
  bar.aliases     = %w[bar bars]
end

RubyUnits::Unit.define("atm") do |atm|
  atm.definition  = RubyUnits::Unit.new("101325 Pa")
  atm.aliases     = %w[atm ATM atmosphere atmospheres]
end

RubyUnits::Unit.define("mmHg") do |mmhg|
  density_of_mercury  = RubyUnits::Unit.new("7653360911758079/562949953421312 g/cm^3") # 13.5951 g/cm^3 at 0 tempC
  mmhg.definition     = RubyUnits::Unit.new("1 mm") * RubyUnits::Unit.new("1 gee") * density_of_mercury
end

RubyUnits::Unit.define("inHg") do |inhg|
  density_of_mercury = RubyUnits::Unit.new("7653360911758079/562949953421312 g/cm^3") # 13.5951 g/cm^3 at 0 tempC
  inhg.definition    = RubyUnits::Unit.new("1 in") * RubyUnits::Unit.new("1 gee") * density_of_mercury
end

RubyUnits::Unit.define("torr") do |torr|
  torr.definition = RubyUnits::Unit.new("1/760 atm")
  torr.aliases    = %w[Torr torr]
end

RubyUnits::Unit.define("psi") do |psi|
  psi.definition  = RubyUnits::Unit.new("1 lbf/in^2")
end

RubyUnits::Unit.define("cmh2o") do |cmh2o|
  density_of_water  = RubyUnits::Unit.new("1 g/cm^3") # at 4 tempC
  cmh2o.definition  = RubyUnits::Unit.new("1 cm") * RubyUnits::Unit.new("1 gee") * density_of_water
  cmh2o.aliases     = %w[cmH2O cmh2o cmAq]
end

RubyUnits::Unit.define("inh2o") do |inh2o|
  density_of_water  = RubyUnits::Unit.new("1 g/cm^3") # at 4 tempC
  inh2o.definition  = RubyUnits::Unit.new("1 in") * RubyUnits::Unit.new("1 gee") * density_of_water
  inh2o.aliases     = %w[inH2O inh2o inAq]
end

# viscosity

RubyUnits::Unit.define("poise") do |poise|
  poise.definition  = RubyUnits::Unit.new("dPa*s")
  poise.aliases     = %w[P poise]
end

RubyUnits::Unit.define("stokes") do |stokes|
  stokes.definition = RubyUnits::Unit.new("1 cm^2/s")
  stokes.aliases    = %w[St stokes]
end

# #energy

RubyUnits::Unit.define("joule") do |joule|
  joule.definition  = RubyUnits::Unit.new("1 N*m")
  joule.aliases     = %w[J joule joules]
end

RubyUnits::Unit.define("erg") do |erg|
  erg.definition  = RubyUnits::Unit.new("1 g*cm^2/s^2")
  erg.aliases     = %w[erg ergs]
end

# power

RubyUnits::Unit.define("watt") do |watt|
  watt.definition = RubyUnits::Unit.new("1 N*m/s")
  watt.aliases    = %w[W Watt watt watts]
end

RubyUnits::Unit.define("horsepower") do |hp|
  hp.definition = RubyUnits::Unit.new("33000 ft*lbf/min")
  hp.aliases    = %w[hp horsepower]
end

# energy
RubyUnits::Unit.define("btu") do |btu|
  btu.definition  = RubyUnits::Unit.new("2320092679909671/2199023255552 J") # 1055.056 J  --- ISO standard
  btu.aliases     = %w[Btu btu Btus btus]
end

RubyUnits::Unit.define("therm") do |therm|
  therm.definition  = RubyUnits::Unit.new("100 kBtu")
  therm.aliases     = %w[thm therm therms Therm]
end

# "small" calorie
RubyUnits::Unit.define("calorie") do |calorie|
  calorie.definition  = RubyUnits::Unit.new("4.184 J")
  calorie.aliases     = %w[cal calorie calories]
end

# "big" calorie
RubyUnits::Unit.define("Calorie") do |calorie|
  calorie.definition  = RubyUnits::Unit.new("1 kcal")
  calorie.aliases     = %w[Cal Calorie Calories]
end

RubyUnits::Unit.define("molar") do |molar|
  molar.definition  = RubyUnits::Unit.new("1 mole/l")
  molar.aliases     = %w[M molar]
end

# potential
RubyUnits::Unit.define("volt") do |volt|
  volt.definition = RubyUnits::Unit.new("1 W/A")
  volt.aliases    = %w[V volt volts]
end

# capacitance
RubyUnits::Unit.define("farad") do |farad|
  farad.definition  = RubyUnits::Unit.new("1 A*s/V")
  farad.aliases     = %w[F farad farads]
end

# charge
RubyUnits::Unit.define("coulomb") do |coulomb|
  coulomb.definition  = RubyUnits::Unit.new("1 A*s")
  coulomb.aliases     = %w[C coulomb coulombs]
end

# conductance
RubyUnits::Unit.define("siemens") do |siemens|
  siemens.definition  = RubyUnits::Unit.new("1 A/V")
  siemens.aliases     = %w[S siemens]
end

# inductance
RubyUnits::Unit.define("henry") do |henry|
  henry.definition  = RubyUnits::Unit.new("1 J/A^2")
  henry.aliases     = %w[H henry henries]
end

# resistance
RubyUnits::Unit.define("ohm") do |ohm|
  ohm.definition  = RubyUnits::Unit.new("1 V/A")
  ohm.aliases     = %w[Ohm ohm ohms]
end

# magnetism

RubyUnits::Unit.define("weber") do |weber|
  weber.definition  = RubyUnits::Unit.new("1 V*s")
  weber.aliases     = %w[Wb weber webers]
end

RubyUnits::Unit.define("tesla") do |tesla|
  tesla.definition  = RubyUnits::Unit.new("1 V*s/m^2")
  tesla.aliases     = %w[T tesla teslas]
end

RubyUnits::Unit.define("gauss") do |gauss|
  gauss.definition  = RubyUnits::Unit.new("100 microT")
  gauss.aliases     = %w[G gauss]
end

RubyUnits::Unit.define("maxwell") do |maxwell|
  maxwell.definition  = RubyUnits::Unit.new("1 gauss*cm^2")
  maxwell.aliases     = %w[Mx maxwell maxwells]
end

RubyUnits::Unit.define("oersted") do |oersted|
  oersted.definition  = RubyUnits::Unit.new(250.0 / Math::PI, "A/m")
  oersted.aliases     = %w[Oe oersted oersteds]
end

# activity
RubyUnits::Unit.define("katal") do |katal|
  katal.definition  = RubyUnits::Unit.new("1 mole/sec")
  katal.aliases     = %w[kat katal]
end

RubyUnits::Unit.define("unit") do |unit|
  unit.definition   = RubyUnits::Unit.new("1/60 microkatal")
  unit.aliases      = %w[U enzUnit units]
end

# frequency

RubyUnits::Unit.define("hertz") do |hz|
  hz.definition   = RubyUnits::Unit.new("1 1/s")
  hz.aliases      = %w[Hz hertz]
end

# angle
RubyUnits::Unit.define("degree") do |deg|
  deg.definition    = RubyUnits::Unit.new(Math::PI / 180.0, "radian")
  deg.aliases       = %w[deg degree degrees]
end

RubyUnits::Unit.define("gon") do |grad|
  grad.definition   = RubyUnits::Unit.new(Math::PI / 200.0, "radian")
  grad.aliases      = %w[gon grad gradian grads]
end

# rotation
RubyUnits::Unit.define("rotation") do |rotation|
  rotation.definition = RubyUnits::Unit.new(2.0 * Math::PI, "radian")
end

RubyUnits::Unit.define("rpm") do |rpm|
  rpm.definition  = RubyUnits::Unit.new("1 rotation/min")
end

# memory
RubyUnits::Unit.define("bit") do |bit|
  bit.definition  = RubyUnits::Unit.new("1/8 byte")
  bit.aliases     = %w[b bit]
end

# currency
RubyUnits::Unit.define("cents") do |cents|
  cents.definition  = RubyUnits::Unit.new("1/100 dollar")
end

# luminosity
RubyUnits::Unit.define("lumen") do |lumen|
  lumen.definition  = RubyUnits::Unit.new("1 cd*steradian")
  lumen.aliases     = %w[lm lumen]
end

RubyUnits::Unit.define("lux") do |lux|
  lux.definition  = RubyUnits::Unit.new("1 lumen/m^2")
end

# radiation
RubyUnits::Unit.define("gray") do |gray|
  gray.definition = RubyUnits::Unit.new("1 J/kg")
  gray.aliases    = %w[Gy gray grays]
end

RubyUnits::Unit.define("roentgen") do |roentgen|
  roentgen.definition = RubyUnits::Unit.new("2.58e-4 C/kg")
  roentgen.aliases    = %w[R roentgen]
end

RubyUnits::Unit.define("sievert") do |sievert|
  sievert.definition  = RubyUnits::Unit.new("1 J/kg")
  sievert.aliases     = %w[Sv sievert sieverts]
end

RubyUnits::Unit.define("becquerel") do |becquerel|
  becquerel.definition  = RubyUnits::Unit.new("1 1/s")
  becquerel.aliases     = %w[Bq becquerel becquerels]
end

RubyUnits::Unit.define("curie") do |curie|
  curie.definition  = RubyUnits::Unit.new("37 GBq")
  curie.aliases     = %w[Ci curie curies]
end

RubyUnits::Unit.define("count") do |count|
  count.definition  = RubyUnits::Unit.new("1 each")
  count.kind        = :counting
end

# rate
RubyUnits::Unit.define("cpm") do |cpm|
  cpm.definition  = RubyUnits::Unit.new("1 count/min")
end

RubyUnits::Unit.define("dpm") do |dpm|
  dpm.definition  = RubyUnits::Unit.new("1 count/min")
end

RubyUnits::Unit.define("bpm") do |bpm|
  bpm.definition  = RubyUnits::Unit.new("1 count/min")
end

# misc
RubyUnits::Unit.define("dozen") do |dozen|
  dozen.definition  = RubyUnits::Unit.new("12 each")
  dozen.aliases     = %w[doz dz dozen]
  dozen.kind = :counting
end

RubyUnits::Unit.define("gross") do |gross|
  gross.definition  = RubyUnits::Unit.new("12 dozen")
  gross.aliases     = %w[gr gross]
  gross.kind = :counting
end

RubyUnits::Unit.define("cell") do |cell|
  cell.definition   = RubyUnits::Unit.new("1 each")
  cell.aliases      = %w[cells cell]
  cell.kind         = :counting
end

RubyUnits::Unit.define("base-pair") do |bp|
  bp.definition   = RubyUnits::Unit.new("1 each")
  bp.aliases      = %w[bp base-pair]
  bp.kind         = :counting
end

RubyUnits::Unit.define("nucleotide") do |nt|
  nt.definition   = RubyUnits::Unit.new("1 each")
  nt.aliases      = %w[nt]
  nt.kind         = :counting
end

RubyUnits::Unit.define("molecule") do |molecule|
  molecule.definition   = RubyUnits::Unit.new("1 each")
  molecule.aliases      = %w[molecule molecules]
  molecule.kind         = :counting
end

RubyUnits::Unit.define("percent") do |percent|
  percent.definition  = RubyUnits::Unit.new("1/100")
  percent.aliases     = %w[% percent]
end

RubyUnits::Unit.define("ppm") do |ppm|
  ppm.definition  = RubyUnits::Unit.new(1) / 1_000_000
end

RubyUnits::Unit.define("ppb") do |ppb|
  ppb.definition  = RubyUnits::Unit.new(1) / 1_000_000_000
end