Cherries the expression logging library

Cherries is a crate that does expression logging as json structure.

Usage

cherries requires rustc 1.37.0 or later. Add this to your Cargo.toml:

yaml [dependencies] cherries = "0.2.3"

Labeling

You can label to leaf with builder or rename with labeled method.

```rust extern crate cherries; use cherries::node::{Leaf, Cherries};

fn main() { // labeling let node = Leaf::new().value(1).name("node").build(); asserteq!(node.name(), &"node".tostring());

// renaming
let node = node.labeled("renamed");
assert_eq!(node.name(), &"renamed".to_string());

} ```

Validation

Validation utilities are in module cherries::validate.

• Validate: Trait that provides extension method validate to Cherry<T>.
• ValidateChain: Struct that allows to chain validate and provides into_result.
• Error: Information struct for validation errors.

```rust extern crate cherries; use cherries::node::{Leaf, Cherry, Cherries}; use cherries::validate::{Validate, ValidateChain, Error};

fn main() { let node = Leaf::new().value(2).name("node").build(); let validated = node .validate("must be even", |v| v % 2 == 0) .validate("must be less than 4", |v| v < 4) .into_result();

assert_eq!(validated, Ok(Leaf::new().value(2).name("node").build()));

let node = Leaf::new().value(1).name("node").build();
let validated = node
    .validate("must be even", |v| v % 2 == 0)
    .validate("must be less than 4", |v| v < 4)
    .into_result();

assert_eq!(
    Err(Error {
        label: "node".to_string(),
        msg: vec![
             "must be even".to_string(),
             "must be less than 4".to_string()
        ],
        tree: "some json".to_string()
    }),
    validated
);

} ```

Get json string

You can get expression tree with json structure using Cherries::to_json().

```rust extern crate cherries; use cherries::node::{Leaf, Cherry, Cherries}; use cherries::validate::{Validate, ValidateChain, Error};

fn main() { let a = Leaf::new().value(2).name("a").build(); let b = Leaf::new().value(3).name("b").build(); let c = Leaf::new().value(4).name("c").build(); let d = Leaf::new().value(1).name("d").build();

let e = a + b;
let f = c - d;
let res = e * f;
println!("{}", res.to_json());

} ```

Output:

json5 { "label":"(mul)", "value":15, "unit":"dimensionless", "subexpr":[ { "label":"(add)", "value":5, "unit":"dimensionless", "subexpr":[ { "label":"a", "value":2, "unit":"dimensionless" }, { "label":"b", "value":3, "unit":"dimensionless" } ] }, { "label":"(sub)", "value":3, "unit":"dimensionless", "subexpr":[ { "label":"c", "value":4, "unit":"dimensionless" }, { "label":"d", "value":1, "unit":"dimensionless" } ] } ] }

Mapping

For example, show you how to use cherries with uom crate (units of measurement). Let's applying method floor with turbofish using map.

```rust extern crate cherries; use cherries::node::{Leaf, Cherry, Cherries}; use cherries::validate::{Validate, ValidateChain, Error}; use uom::si::f32::*; use uom::si::length::{meter};

fn main() { let x = Leaf::new() .name("x") .value(Length::new::(2.1)) .build(); let res = x.map(|x| x.floor::()).labeled("floor"); asserteq!(&Length::new::(2.0), res.quantity()); asserteq!(&"floor".tostring(), res.name()); println!("{}", res.tojson()); } ```

Output:

json5 { "label":"floor", "value":2, "unit":"m^1", "subexpr":[ { "label":"x", "value":2.1, "unit":"m^1" } ] }

License

Licensed under MIT LICENSE.