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https://github.com/Udiknedormin/NimUnits
Statically-typed quantity units library for Nim language.
https://github.com/Udiknedormin/NimUnits
Last synced: about 2 months ago
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Statically-typed quantity units library for Nim language.
- Host: GitHub
- URL: https://github.com/Udiknedormin/NimUnits
- Owner: Udiknedormin
- License: mit
- Created: 2018-04-15T17:01:52.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2018-12-23T20:58:24.000Z (about 6 years ago)
- Last Synced: 2024-08-03T03:05:41.331Z (5 months ago)
- Language: Nim
- Size: 44.9 KB
- Stars: 36
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-nim - units - Statically-typed quantity units library for the Nim language. (Science / Embedded)
README
# Units
[](https://github.com/yglukhov/nimble-tag)
This module provides statically-typed units of measure. Given a unit
system, any basic floating-point operations compatible with their units
can be done, e.x. addition, substraction, multiplication, division,
natural power. Roots can be incompatible, depending on units' powers.
Several macros with super-easy syntax are provided:
- unitSystem – creates a unit system of basic quantities
- unitQuanity – adds derivated quantities to the system
- unitAlias – provides new units, which support arbitrary functions
- unitPrefix – provides unit prefixes
- unitAbbr – provides abbreviations for units with prefixes
Both SI unit system and SI unit prefixes are available,
in si and prefixes submodules respectively. Note units.si module
exposes si prefixes too.
As for now, this module doesn't provide custom type mismatch
communicates, but Nim's own ones suffice in most cases.
Example usage of si module and display of error-handling:
```nim
import units.si
type Metal = object
name: string
rho: Density
cw: Energy / (Mass * Temperature)
k: Power / (Length * Temperature)
const copper = Metal(name: "copper",
rho: 8920.kg * 1.m^-3,
cw: 380.J / (1.kg*1.K),
k: 401.W / (1.m*1.K))
proc heating(m: Metal, E: Energy, vol: Volume): Temperature =
E / (m.cw * vol * m.rho)
echo heating(copper, 10.W * 3.s, 1.m^3) # ok
echo heating(copper, 10.W, 1.m^3)
# FILE.nim(LINE, 13) Error: type mismatch: got (Metal, Power, Volume)
# but expected one of:
# proc heating(m: Metal; E: Energy; vol: Volume): Temperature
proc heatingErr(m: Metal, E: Energy, vol: Volume): Temperature =
E / (vol * m.rho)
# FILE.nim(LINE, 3) Error: type mismatch: got (AbsorbedDose)
# but expected 'Temperature = Si[0, 0, 0, 0, 1, 0, 0]'
```
Declaring user-defined systems, quantities, units and prefixes is easy
and provides (hopefully) useful error messages in case of error:
```nim
import units
unitSystem Imperial: # line N
Length: yards # line N+1
Mass: pounds # line N+2
Time: seconds # line N+3
# FILE.nim(N+1, 11) Error: no abbreviated unit name found
# for 'Length: yards', 'Length: yards(abbr)' form expected
# (maybe try 'Length: yards(y)'?)
```
```nim
import units, units.si
unitAlias:
x.yards(ya) = x * 0.9144
# FILE.nim(LINE, 19) Error: unit alias implementation
# in form expr(x).unit expected but got 'x * 0.9144'
# (maybe try '(x * 0.9144).unit'?)
```
## Experimental features
Experimental mode can be enabled using either via call to
``unitsExperimental`` template in ``units`` or importing
``units.unitsExperimental`` module.
As for now, experimental features are the following:
- value-less units operations
Example of usage:
```nim
import units.unitsExperimental
import units.si
let v = 10.m/s
echo v # 10 m s^-1
# Attention! Dot binds stronger than other operators!
let area1 = 10.m^2
echo area1 # 100 m^2
let area2 = 10 * m^2
echo area2 # 10 m^2
# Units can also be binded to variables:
const m2 = m^2
let area3 = 10.m2
echo area3 # 10 m^2
```
## Installation
The library is available via nimble:
```bash
nimble install units
```
No initialization is needed, it's ready to use out of the box.