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.
cpc lets you mix units, so for example 1 km - 1m results in Number { value: 999, unit: Meter }.
To install the CLI using cargo:
cargo install cpc
To install the CLI directly, grab the appropriate binary from cpc's Releases page on GitHub, then place it wherever you normally place binaries on your OS (On Windows, you may need to edit your PATH variable or something).
cpc '20c to f'
If you installed the binary somewhere that doesn't make binaries global, you would need to specify the path: ```sh /usr/local/bin/custom/cpc '10+10'
./cpc '1" in cm' ```
To install the library as a Rust dependency, add cpc to your Cargo.toml like so:
toml
[dependencies]
cpc = "1.*"
```rs use cpc::{eval, Unit::*}
match eval("3m + 1cm", true, Celcius) { Ok(answer) => { // answer: Number { value: 301, unit: Unit::cm } println!("Evaluated value: {} {:?}", answer.value, answer.unit) }, Err(e) => { println!(e) } } ```
``` 3 + 4 * 2
8 % 3
(4 + 1)km to light years
10m/2s * 5s
1 lightyear * 0.001mm in km2
1m/s + 1mi/h in kilometers per h
round(sqrt(2)^4)! liters
10% of abs(sin(pi)) horsepower to watts ```
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.
In my case, I can expect eval() to take 100-200ms, and this scales pretty alright. However, putting numbers with a lot of digits into functions result in pretty poor performance. log(e) is one of the worst, and takes 500ms for me.
cpc returns Results with basic strings as errors. Just to be safe, you may want to handle panics (You can do that using std::panic::catch_unwind).
Install Rust. This project was built in Rust 1.45.
Run cpc with a CLI argument as input:
cargo run -- '100ms to s'
Run with debugging, which shows some extra logs:
cargo run -- '100ms to s' --debug
Run tests:
cargo test
Build:
cargo build
In src/units.rs, units are specified like this:
```rs
pub enum UnitType {
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 is 1, then a minute's weight is 1000.
I have found translatorscafe.com and calculateme.com to be good websites for unit convertion. Wikipedia is worth looking at as well.
Make sure to also add a test for each unit. The tests look like this:
rs
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) in lexer.rs. Here's one example:
rs
// ...
match string {
"h" | "hr" | "hrs" | "hour" | "hours" => tokens.push(Token::Unit(Hour)),
// etc
}
// ...
6'4" syntax, like 3'+2'4". Currently needs to be written like 3'+3'+4"one billion
Nice list of units: https://support.google.com/websearch/answer/3284611 - Currency: How would you go about dynamically updating the weights? - Fuel consumption - Data transfer rate - Color codes - Force - Roman numerals - Angles - Electric current, capacitance, charge, conductance, volts - Flow rate - Frequency
cross:
cargo install cross
<target> is the platform you're building for:
sh
cross build --release --target <target>
x86_64-apple-darwin (Only works on macOS)x86_64-unknown-linux-muslx86_64-pc-windows-gnucross supports
The compiled binaries will now be available inside target/<target>/release/. The filename will be either cpc or cpc.exe.CHANGELOG.mdCargo.toml and run cargo checkv1.0.0cargo login and following the instructions
cargo publish --dry-run
cargo publish