every-range

This crate implements an extension to Iterator, which features an every_range method on any Iterator with an Item of Range<usize>.

EveryRangeIter iterates over Ranges and "fill in" missing ranges, i.e. the gap between two consecutive ranges. The original ranges and the generated ones, can be distinguished by the Included and Excluded enum variants.

EveryRangeIter is useful when the ranges being iterated are related to substrings that later are used to replaced parts in a string.

Usage

Add this to your Cargo.toml:

[dependencies]
every-range = "0.1"

Releases

Release notes are available in the repo at CHANGELOG.md.

Example: How does it work?

use every_range::EveryRange;

// Lets use text as an example, but it could be anything
let text = "Foo rust-lang.org Bar
Baz crates.io Qux";

// Get some ranges from somewhere
let ranges = vec![
    4..17,  // "rust-lang.org"
    26..35, // "crates.io"
];

// `text.len()` tells `EveryRange` the end, so it knows
// whether to produce an extra range after or not
let iter = ranges.into_iter().every_range(text.len());

// The input `ranges` result in `Included` every other range is `Excluded`
for (kind, range) in iter {
    println!("{:?} {:>2?} - {:?}", kind, range.clone(), &text[range]);
}

This will output the following:

Excluded  0.. 4 - "Foo "
Included  4..17 - "rust-lang.org"
Excluded 17..26 - " Bar\nBaz "
Included 26..35 - "crates.io"
Excluded 35..39 - " Qux"

Example: "Autolink" or HTMLify URLs

Using every_range it is easy to collect ranges or substring into a String.

use std::borrow::Cow;
use every_range::{EveryRange, EveryRangeKind};

let text = "Foo rust-lang.org Bar
Baz crates.io Qux";

// For URLs input ranges could be produced by linkify
let ranges = vec![
    4..17,  // "rust-lang.org"
    26..35, // "crates.io"
];

let output = ranges
    .into_iter()
    .every_range(text.len())
    .map(|(kind, range)| {
        if kind == EveryRangeKind::Included {
            let url = &text[range];
            format!("<a href=\"{0}\">{0}</a>", url).into()
        } else {
            Cow::Borrowed(&text[range])
        }
    })
    .collect::<Vec<_>>()
    .concat();

println!("{}", output);

This will output the following:

Foo <a href="rust-lang.org">rust-lang.org</a> Bar
Baz <a href="crates.io">crates.io</a> Qux