Repository files navigation

calculation + conversion

cpc parses and evaluates strings of math, with support for units and conversion. 128-bit decimal floating points are used for high accuracy.

It also lets you mix units, so for example1 km - 1m results in999 Meter.

List of all supported units

Try it out atcpc.kasper.space

Install usingcargo:

cargo install cpc

To install it manually, grab the appropriate binary from theGitHub Releases page and place it wherever you normally place binaries on your OS.

cpc '2h/3 to min'

3 + 4 * 28 % 3(4 + 1)km to light years10m/2s * 5 trillion s1 lightyear * 0.001mm in km21m/s + 1mi/h in kilometers per hround(sqrt(2)^4)! liters10% of abs(sin(pi)) horsepower to watts

• Normal numbers
• Time
• Length
• Area
• Volume
• Mass
• Digital storage (bytes etc)
• Energy
• Power
• Electric current
• Resistance
• Voltage
• Pressure
• Frequency
• Speed
• Temperature

Addcpc as a dependency inCargo.toml.

use cpc::eval;use cpc::units::Unit;matcheval("3m + 1cm",true,Unit::Celsius,false){Ok(answer) =>{// answer: Number { value: 301, unit: Unit::Centimeter }println!("Evaluated value: {} {:?}", answer.value, answer.unit)},Err(e) =>{println!("{e}")}}

cpc uses 128-bit Decimal Floating Point (d128) numbers instead of Binary Coded Decimals for better accuracy. The result cpc gives will still not always be 100% accurate. I would recommend rounding the result to 20 decimals or less.

InstallRust.

Run cpc with a CLI argument as input:

cargo run -- '100ms to s'

Run in verbose mode, which shows some extra logs:

cargo run -- '100ms to s' --verbose

Run tests:

cargo test

Build:

cargo build

Nice resources for adding units:

• https://github.com/ryantenney/gnu-units/blob/master/units.dat
• https://support.google.com/websearch/answer/3284611 (unit list)
• https://translatorscafe.com/unit-converter (unit conversion)
• https://calculateme.com (unit conversion)
• https://wikipedia.org

Insrc/units.rs, units are specified like this:

pubenumUnitType{Time,// etc}// ...create_units!(Nanosecond:(Time, d128!(1)),Microsecond:(Time, d128!(1000)),// etc)

The number associated with a unit is it's "weight". For example, if a second's weight is1, then a minute's weight is60.

Make sure to also add a test for each unit. The tests look like this:

assert_eq!(convert_test(1000.0,Meter,Kilometer),1.0);

Basically, 1000 Meter == 1 Kilometer.

Text is turned into tokens (some of which are units) inlexer.rs. Here's one example:

// ...match string{"h" |"hr" |"hrs" |"hour" |"hours" => tokens.push(Token::Unit(Hour)),// etc}// ...

• Support for conversion between Power, Current, Resistance and Voltage. Multiplication and division is currently supported, but not conversions using sqrt or pow.
• E notation, like 2E+10
• Unit types
  • Currency: How to go about dynamically updating the weights?
    • https://api.exchangerate-api.com/v4/latest/USD
    • https://www.coingecko.com/en/api
    • https://developers.coinbase.com/api/v2
  • Timezones
  • Binary/octal/decimal/hexadecimal/base32/base64
  • Fuel consumption
  • Data transfer rate
  • Color codes
  • Force
  • Roman numerals
  • Angles
  • Flow rate

1. UpdateCHANGELOG.md
2. Bump the version number inCargo.toml
3. Runcargo test
4. Create a git tag in formatv#.#.#
5. Add release notes to the generated GitHub release and publish it
6. Runcargo publish