Vectors

A vector is a native data structure of Rune which is a dynamic list of values. A vector isn't typed, and can store any Rune values.

pub fn main() {
    let values = ["Hello", 42];

    println!("{}", values[0]);
    println!("{}", values.1); // items in vectors can be accessed like tuple fields.

    for v in values {
        println!("{}", v);
    }
}

$> cargo run --bin rune -- run scripts/book/vectors/vectors.rn
Hello
42
Hello
42

As you can see, you can iterate over a vector because it implements the iterator protocol. It is also possible to create and use an iterator manually using Vec::iter, giving you more control over it.

pub fn main() {
    let values = ["Hello", 42];

    for v in values.iter().rev() {
        println!("{}", v);
    }
}

$> cargo run --bin rune -- run scripts/book/vectors/vectors_rev.rn
42
Hello

Using vectors from Rust

Vectors are represented externally as the standard Vec.

use rune::termcolor::{ColorChoice, StandardStream};
use rune::{Diagnostics, Vm};

use std::sync::Arc;

fn main() -> rune::support::Result<()> {
    let context = rune_modules::default_context()?;
    let runtime = Arc::new(context.runtime()?);

    let mut sources = rune::sources! {
        entry => {
            pub fn calc(input) {
                let output = 0;

                for value in input {
                    output += value;
                }

                [output]
            }
        }
    };

    let mut diagnostics = Diagnostics::new();

    let result = rune::prepare(&mut sources)
        .with_context(&context)
        .with_diagnostics(&mut diagnostics)
        .build();

    if !diagnostics.is_empty() {
        let mut writer = StandardStream::stderr(ColorChoice::Always);
        diagnostics.emit(&mut writer, &sources)?;
    }

    let unit = result?;
    let mut vm = Vm::new(runtime, Arc::new(unit));

    let input = vec![1, 2, 3, 4];
    let output = vm.call(["calc"], (input,))?;
    let output: Vec<i64> = rune::from_value(output)?;

    println!("{:?}", output);
    Ok(())
}

$> cargo run --example vector
[10]

If you have a vector which has values of non-uniform types, you can use VecTuple to deal with them.

use rune::runtime::VecTuple;
use rune::termcolor::{ColorChoice, StandardStream};
use rune::{Diagnostics, Vm};

use std::sync::Arc;

fn main() -> rune::support::Result<()> {
    let context = rune_modules::default_context()?;
    let runtime = Arc::new(context.runtime()?);

    let mut sources = rune::sources! {
        entry => {
            pub fn calc(input) {
                let a = input[0] + 1;
                let b = format!("{} World", input[1]);
                [a, b]
            }
        }
    };

    let mut diagnostics = Diagnostics::new();

    let result = rune::prepare(&mut sources)
        .with_context(&context)
        .with_diagnostics(&mut diagnostics)
        .build();

    if !diagnostics.is_empty() {
        let mut writer = StandardStream::stderr(ColorChoice::Always);
        diagnostics.emit(&mut writer, &sources)?;
    }

    let unit = result?;
    let mut vm = Vm::new(runtime, Arc::new(unit));

    let input: VecTuple<(i64, String)> = VecTuple::new((1, String::from("Hello")));
    let output = vm.call(["calc"], (input,))?;
    let VecTuple((a, b)): VecTuple<(u32, String)> = rune::from_value(output)?;

    println!("({:?}, {:?})", a, b);
    Ok(())
}

$> cargo run --example vec_tuple
(2, "Hello World")