Rink’s query language follows a somewhat natural language style for its syntax. Many expressions like 3.5 meters to feet will work without any modification. This manual is meant for those who want to get a deeper understanding of the query language.
In order to understand Rink, an understanding of units themselves is required. Fundamentally, a unit is a way of assigning a concrete value to a specific quantity such as length, volume, energy, power, current, etc. Each quantity can be reduced into other quantities (for example, area is length × length), except for 7 base units.
The 7 base units (as well as the physical quantities they represent):
-
meter (length)
-
second (time)
-
kilogram (mass)
-
ampere (current)
-
kelvin (temperature)
-
mol (amount of substance)
-
candela (human-subjective luminous intensity)
In addition, Rink defines a few non-SI base units:
-
euro (money)
-
bit (information)
-
radian (angle)
-
steradian (solid angle)
-
wholenote (musical note length)
-
IU (biological activity)
Each of these quantities is treated as irreducible. The 7 base units are the foundations of SI, and customary systems as well. (Customary systems are defined in terms of SI.)
Every unit is composed of two parts: A numerical value, and its
dimensionality. The dimensionality is how a unit relates itself to
the base units. Each base unit is raised to a certain power to
construct the dimensionality. For example, the dimensionality of the
quantity of acceleration is length^1 × time^-2 and then the rest of
the base units are to the 0th power, which is to say that they do not
matter. Two units are considered conformable if they have matching
dimensionalities, and they can then be used in conversions.
Because each unit has a numerical part, it is possible to do normal math on them*.
-
Adding two units produces a new unit with matching dimensionality.
-
Multiplying two units produces a new unit with its dimensionality as each base unit multiplied together, e.g. velocity (
length time^-1) * hertz (time^-1) = acceleration (length time^-2). -
Dividing two units is like multiplication, but taking away from the base units. A unit divided by itself is dimensionless, it has no quantity. Normal numbers are dimensionless.
Because of this, units are essentially a special type of number. As such, Rink is essentially a calculator which takes dimensionality into account.
It is important to remember the differences between mass and weight when working with mass and force units. Here are some tips:
-
Mass doesn’t change depending on the amount of gravity, and directly influences momentum.
-
Weight is the amount of downward force on an object due to gravity.
-
Mass is measured in kilograms or pounds.
-
Weight is measured in newtons, kilogram force (kgf), or pound force (lbf).
-
When someone says something weighs some amount of kg or lb, they’re saying it has a weight of that number of kgf or lbf. This includes things like weight on the moon. (Don’t correct anyone using this common figure of speech.)
-
A scale displays an estimate of mass by measuring the force applied to it divided by its calibrated measurement of the acceleration of gravity. Its mass estimate would be incorrect on other planets unless it was recalibrated. You can also think of the displayed value as being weight in kgf or lbf.
-
You can compute weight by multiplying mass by gravity. Both kgf and lbf have earth gravity as part of their definition, so when you multiply kg or lb by gravity you get the same numerical values back, but with kgf or lbf units.
> 10.1e2
1010 (dimensionless)
> 10
10 (dimensionless)
> 0x10
16 (dimensionless)
> 0o10
8 (dimensionless)
> 0b10
2 (dimensionless)
> 9999999999999
approx. 9.99999e12 (dimensionless)
> 1.001
1.001 (dimensionless)
> 1e100
1.0e100 (dimensionless)Decimal numbers can be written with an integer component, an
after-decimal-point component, and an exponent. Numbers can optionally
have either U+2009 THIN SPACE or an underscore (_) for digit place
separators.
The decimal point is always written with a dot (.), not a comma or
other marker. If the decimal point is provided, it must be followed by
more digits. (1. is not allowed.)
The exponent starts with an e, followed by an integer with an
optional sign. The exponent is shorthand for writing out *
10^exp. There can be no spaces within the number other than allowed
digit separators. (10 e10 is not allowed.)
Hexadecimal, octal, and binary integers can be written using 0x,
0o, and 0b prefixes, respectively. These literals do not currently
support decimal points or exponents.
Numbers can be written with a fraction, and can be written in
scientific notation. 1e24 is short for 1 * 10^24.
> 3 4 m 5 s
60 m s
> 3 * 4 m 5 s
60 m sMultiplication can be either by juxtaposition (that is, without any symbol) or using an explicit * operator.
> 10 km / 5 m
2000 (dimensionless)
> 1|2 m
0.5 m (length)There are two division operators, for separate purposes. / has lower
precedence than multiplication, and is used mainly for separating two
halves of an entire expression. | has higher precedence than
multiplication, and is used mainly for fractions of integers.
> 1 * 2 + 1 * 2
4 (dimensionless)
> 12 meters + 5 feet
13.524 m (length)Addition and subtraction have lower precedence than multiplication and division.
> 12 ft^2
435483/390625, approx. 1.114836 m^2 (area)Powers have higher precedence than multiplication. Both ^ and **
can be used.
> 11 mod 3
2 (dimensionless)
> meter mod foot
85.6 millimeter (length)The mod operator can be used to find the remainder of division. It has
the same precedence as *. Requires both inputs to have the same
dimensionality.
> 1 << 24
16777216 (dimensionless)
> 16 >> 2Equivalent to multiplying or dividing by a power of two. The right side must be dimensionless.
4 (dimensionless)
> 0b1010 and 0b1100 to base 2
1000 (dimensionless)
> 0b1010 or 0b1100 to base 2
1110 (dimensionless)
> 0b1010 xor 0b1100 to base 2
110 (dimensionless)Bitwise operators are supported. The inputs must be dimensionless, and also must be integers.
> 12 °C
285.15 K (temperature)Temperature scales are operators with higher precedence than addition, and lower than multiplication. See the Temperature conversion section for more detailed syntax.
> 2000 kcal -> potato = 164 kcal
500/41, approx. 12.19512 potato (energy)An equals expression is one which simultaneously defines a new unit with the right-hand side, names it using the left-hand side, and then produces it as its result. This is useful for customizing the output of the right-hand side of a conversion or converting into things that don’t currently have units such as the amount of calories in a potato.
> 12 'core' hour / 3 'core' -> minutes
240 minutes (time)A unit name which is wrapped in quotation marks will not be checked for whether it exists when it is evaluated. This means you can wrap anything in quotes to in effect produce a new base unit for the purposes of a single calculation. This can be useful for doing calculations in terms of things which are otherwise dimensionless.
> 100 ohm + 50 ohm
150 ohm (resistance)
> ANS * 10 mA
1.5 volt (electrical_potential)The result of the previous query can be accessed with _, ans or
ANS, which can be convenient for breaking up calculations into
multiple steps. Note that when rink returns an error occurs, the
previous result is kept. Also, currently only the results of
mathematical expressions are stored, the results for conversions aren’t.
Units can be prefixed with SI prefixes as well as a number of non-SI prefixes, such as: quarter, double, kibi, mebi, ⅞.
Rink will accept plural unit names as well.
> meter -> feet
3.280839 foot (length)
> 12 °C -> °F
53.6 °F (temperature)Conversions are done with the →, to, in operators.
The left hand side of the conversion is an arbitrary expression, and the right hand side is one of:
-
An arbitrary expression
-
A temperature scale (celsius, fahrenheit, and several historical scales)
-
A unit list (e.g.
hour;min;sec) -
A timezone (e.g.
"US/Pacific")
> 2^17 seconds -> hour;min;sec
36 hour, 24 minute, 32 s (time)
> 2 km -> mi;ft
1 mile, 1281.679 foot (length)
> liter -> cup;tbsp;tsp
4 uscup, 3 ustablespoon, 1.884136 usteaspoon (volume)A unit list is a comma- or semicolon- delimited list of units with the same dimensionality, which can be used for breaking down numbers into more familiar quantities.
> 12 °C
285.15 K (temperature)
> 12 degC
285.15 K (temperature)
> 12 celsius
285.15 K (temperature)Temperature scales in Rink are handled a little specially, because only Kelvin and Rankine (the absolute zero version of Fahrenheit) start at absolute zero. As such, they are operators, not units. These operators have looser binding precedence than multiplication, but tighter than addition.
Available temperature scales:
degC,°C,celsius,℃-
Celsius, the standard scale in most countries.
degF,°F,fahrenheit,℉-
Fahrenheit, the scale used in households across the United States.
degRé,°Ré,degRe,°Re,réaumur,reaumur-
Réaumur, A historical scale once used throughout Europe.
degRø,°Rø,degRo,°Ro,rømer,romer-
Romer, Another historical scale.
degN,°N,degnewton-
Newton, A historical scale created by Isaac Newton.
degDe,°De,delisle-
Delisle, A historical scale which, alongside the original Celsius scale, is reversed from the scales we are used to today. Its zero point is boiling water, and the freezing point of water is 150°De.
Note that these temperature scale measurements are absolute measurements, not differences. If you wish to say something like "a difference of 1°C", then you must use the absolute scale for the scale you’re using. These are:
-
For Celsius, kelvin
K -
For Fahrenheit, Rankine
degR -
For Réaumur,
reaumur_absolute(absolute as in the zero point is absolute zero) -
For Rømer,
romer_absolute -
For Newton,
newton_absolute -
For Delisle,
delisle_absolute
> 1000 -> hex
3e8 (dimensionless)
> 10000 -> base 36
7ps (dimensionless)
> pi meter -> hex meter
approx. 3.243f6a meter (length)Base modifiers are specified with base followed by a number,
followed by the rest of your conversion. Allowed bases are currently 2
through 36. There are some special base names which are also
recognized:
hex,hexadecimal,base16-
Base 16.
oct,octal,base8-
Base 8.
bin,binary,base2-
Base 2.
> 2^128 -> digits
340282366920938463463374607431768211456 (dimensionless)
> 1/3937 -> digits
0.[000254000508001016002032004064008128016256032512065024130048260096520193040386080772161544323088646177292354584709169418338836677673355346710693421386842773685547371094742189484378968757937515875031750063500127, period 210]... (dimensionless)
> googol -> digits
10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 (dimensionless)
> mass of electron -> eng
approx. 910.9383e-33 kilogram (mass)
> 3 foot -> frac
1143/1250 meter (length)Digits modifiers are specified with digits optionally followed by a
number, before the base modifier and before the rest of the
conversion. Any number of digits are allowed, but large amounts may
not succeed.
The function of this modifier is that it forces the entire integer part to be printed (i.e., scientific notation will not be used), and then it prints an additional n digits, using the default if not specified.
Trancendental numbers currently cannot be precisely represented, so asking for many digits of pi or e will produce unsatisfying results.
Rink makes an attempt to find recurring decimals. If you ask it to print enough digits, it will find them.
Trigonometric and logarithmic functions are currently implemented using a machine-float fallback, because their results cannot be precisely represented as finite rationals. Because of this, asking for many digits of such numbers will also produce unsatisfying results.
frac, fraction, ratio are all equivalent. They will print
the rational fraction that Rink internally represents the number using.
sci, scientific will force the use of scientific notation, even for
small numbers.
eng, engineering are similar to the default format, where it uses
scientific notation only for large numbers. However, when it does use
scientific notation, it rounds down to every third power.
> units for power
Units for kg m^2 / s^3 (power): VA, airwatt, boilerhorsepower, brhorsepower,
donkeypower, electrichorsepower, horsepower, lusec, mbh, metrichorsepower,
poncelet, sccm, sccs, scfh, scfm, slph, slpm, solarluminosity,
tonrefrigeration, waterhorsepower, wattThe units for, units of, and units commands will find more units which match the dimensionality of the one specified.
> factorize velocity
Factorizations: velocity; frequency length; area viscosity;
acceleration time; length^2 viscosity
> factorize power
Factorizations: power; force velocity; radiant_intensity solid_angle;
area radiosity; length spectral_flux_wavelength; radiation_dose spectral_exposure_frequency;
spectral_irradiance_wavelength volume; temperature thermal_conductance;
energy frequency; current^2 resistance; ...Unit factorization is what Rink names the process of finding quantities which can be multiplied together to produce the original quantity. This can be useful for discovering new ways to construct a unit.
> #jan 01, 1970#
1970-01-01 00:00:00 +00:00 (46 years ago)
> now - #jan 01, 1970# -> gigaseconds
1.472083 gigaseconds (time)
> #2016-08-24# + 500 weeks
2026-03-25 00:00:00 +00:00 (in 9 years)In addition to handling units, Rink is also capable of doing some calculations with dates and times.
Converting to a timezone:
> now
2022-08-08 21:19:56.990897100 -07:00 (now)
> now -> "Europe/London"
2022-08-09 05:20:03.656075600 BST (now)Converting to a fixed offset:
> now -> +01:00
2022-08-09 05:20:30.080703900 +01:00 (now)Inputting a time with an offset:
> #apr 1, 2016 12:00:00 +01:00#
2016-04-01 12:00:00 +01:00 (6 years ago)> milk
milk: density = 242 gram -> approx. 236588.2 millimeter^3
> gallon milk
milk: volume = approx. 3785411.7 millimeter^3; mass = 3.872 kilogram
> egg
egg: USA large egg. mass_shelled = 50 gram; mass_white = 30 gram;
mass_yolk = 18.6 gram; volume = approx. 46824.75 millimeter^3;
volume_white = approx. 29573.52 millimeter^3;
volume_yolk = approx. 17251.22 millimeter^3
> egg_shelled of kg egg
20 (dimensionless)
> gallon gasoline -> btu
gasoline: volume = approx. 3785411.7 millimeter^3; energy_HHV = 125000 btu; energy_LHV = 115000 btuSubstances are how Rink organizes the physical properties of materials, objects, both countable and uncountable. Each substance has a name, an associated amount (defaulting to dimensionless 1), and a set of associated properties.
Each property maps a named input into a named output and vice versa, and has a name itself. Countable objects often have properties with an input being dimensionless, so that you do not need to specify an amount to extract the property.
The properties of a substance are accessed with the of operator (<_property_> of <_substance_>), which reads a multiplication expression following it, so you may have to wrap it in parentheses.
Substances can be used in conversions, and can be added and multiplied
to transform them. Multiplication will change the amount of the
substance you have, so that you can write kg egg to specify one
kilogram of eggs. Addition will combine certain properties (currently
only molar_mass) to create a new substance entirely. Conversions of
substances allow you to get multiple results simultaneously, for
example if there are multiple different measurements of some property
of the substance available.
If the result of a calculation results in a substance, Rink will show all of the properties applicable for the given amount.
The full list of units is specified in the file definitions.units (see
rink-defs(5)), but a small list of the most helpful ones will be listed
here. It is intended that most units should be easy to guess the names
of.
-
Newton
N(force) -
Pascal
Pa(pressure) -
Joule
J(energy) -
Watt
W(power) -
Coulomb
C(charge) -
Volt
V(electrical potential) -
Ohm (electrical resistance)
-
Siemens
S(electrical conductance) -
Farad
F(capacitance) -
Weber
Wb(magnetic flux) -
Henry
H(inductance) -
Tesla
T(magnetic flux density) -
Hertz
Hz(frequency) -
Lumen
lm(luminous flux) -
Lux
lx(illuminance) -
Gray
Gy(radiation dose) -
Katal
kat(catalytic activity)
- Compounds and materials
-
-
Water
water -
Ammonia
ammonia -
Freon
freon -
Tissue
tissue -
Diamond
diamond -
Graphite
graphite -
Water ice
ice -
Asphalt
asphalt -
Brick
brick -
Concrete
cocnrete -
Silica glass
glass_silica -
Flint glass
glass_flint -
Pyrex glass
glass_pyrex -
Gypsum
gypsum -
Marble
marble -
Sand
sand -
Soil
soil -
Air
air
-
- Particles
-
-
Electron
electron -
Proton
proton -
Neutron
neutron -
Deuterium nucleus
deuteron -
Muon
muon -
Helium nucleus
helion -
Tau
tauparticle -
Alpha
alphaparticle -
Tritium nucleus
triton
-
- Celestial bodies
-
-
Sun
sun -
Mercury
mercury_planet -
Venus
venus -
Earth
earth -
Earth’s moon
moon -
Mars
mars -
Jupiter
jupiter -
Saturn
saturn -
Uranus
uranus -
Neptune
neptune -
Pluto
pluto
-
- Fuels
-
-
Crude oil
oil -
Coal
coal -
Natural gas
naturalgas -
Charcoal
charcoal -
Wood
wood -
Ethanol
ethanol -
Diesel
diesel -
Gasoline
gasoline -
Heating oil
heating_oil -
Fuel oil
fueloil -
Propane
propane -
Butane
butane
-
- Foods
-
-
Butter
butter -
Clarified butter
butter_clarified -
Cocoa butter
cocoa_butter -
Vegetable shortening
shortening -
Vegetable oil
vegetable_oil -
Olive oil
olive_oil -
Flour
cakeflour,flour,breadflour -
Corn starch
cornstarch -
Cocoa
dutchcocoa,cocoa -
Heavy cream
heavycream -
Milk
milk -
Sour cream
sourcream -
Molasses
molasses -
Corn syrup
corrnsyrup -
Honey
honey -
Sugar
sugar -
Powdered sugar
powdered_sugar -
Brown sugar
brownsugar_light,brownsugar_dark -
Baking powder
baking_powder -
Salt
salt,koshersalt -
Egg
egg
-
Elements 1 through 118, by name (e.g. helium)
-
Pi
pi -
Speed of light
c -
Planck Constant
planck_constant -
Gravitational Constant
G -
Avogadro’s number
avogadro -
Gas Constant
gasconstant -
Boltzmann Constant
boltzmann -
Earth Gravity
gravity,force -
Earth Atmosphere Density
atm
These are only available if live currency fetching is enabled. (See rink(5).)
-
EU Euro
EUR,€ -
US dollar
USD,$,dollar -
Japan yen
JPY,¥,yen -
Bulgaria lev
BGN -
Czech koruna
CZK -
Denmark kroner
DKK -
UK pound
GBP,£ -
Hungary forint
HUF -
Poland złoty
PLN -
Romania lei
RON -
Sweden krona
SEK -
Switzerland franc
CHF -
Norway krone
NOK -
Croatia kuna
HRK -
Russia ruble
RUB,₽ -
Turkey lira
TRY,₺ -
Australia dollar
AUD,A$ -
Brazil real
BRL,R$ -
Canada dollar
CAD,C$ -
PRC yuan
CNY -
Hong Kong dollar
HKD,H$ -
Indonesia rupiah
IDR -
Israel shekel
ILS,₪ -
India rupee
INR,₹ -
South Korea won
₩ -
Mexico dollar
MXN,mex$ -
Malaysia ringgit
MYR -
New Zealand dollar
NZD,NZ$ -
Phillipines piso
PHP,₱ -
Singapore dollar
SGD,S$ -
Thailand baht
THB,฿ -
South Africa rand
ZAR
Currently, all of these result in machine float fallback, because their results are real numbers that cannot be precisely represented as rationals.
-
sqrt(x): Square root, √x. -
exp(x): The exponential function, e^x. -
ln(x): The natural logarithm, log_e(x). -
log(x,y): Logarithm in base y, log_y(x). -
log2(x): Logarithm in base 2, log_2(x). -
log10(x): Logarithm in base 10, log_10(x). -
hypot(x,y): The length of the hypotenuse of a right-angle triangle given adjacent edges of length x and y. -
sin(x): The sine function. -
cos(x): The cosine function. -
tan(x): The tangent function. -
asin(x): Inverse sine, or arcsine. -
acos(x): Inverse cosine, or arccosine. -
atan(x): Inverse tangent, or arctangent. -
atan2(x, y): Four-quadrant arctangent, which can be used to reverse sine+cosine back into an angle. -
sinh(x): Hyperbolic sine. -
cosh(x): Hyperbolic cosine. -
tanh(x): Hyperbolic tangent. -
asinh(x): Inverse hyperbolic sine function. -
acosh(x): Inverse hyperbolic cosine function. -
atanh(x): Inverse hyperbolic tangent function.