Differ is a library for finding the differences between two sequences.
The sequences can be vectors of lines, strings (e.g., words), characters,
bytes, or of any custom “item” type so long as it implements the Hash
and Eq
traits.
For your Cargo.toml
add this to the [dependencies]
section:
differ = "1.0.1"
If you want to be able to serialize or deserialize Match
es, Span
s, or
Tag
s, then use:
differ = { version = "1.0.1", features = ["use_serde"] }
Then, in your crate root, for Rust 2015 add extern crate differ
, and for
Rust 2018 add use differ
.
These examples are in the file examples/simple.rs
. For more examples see
src/tests.rs
.
Here lines are compared, but it could just as easily be strings (e.g., words by splitting on whitespace), or characters or bytes.
use differ::{Differ, Tag};
let a = "foo\nbar\nbaz\nquux".lines().collect::<Vec<_>>();
let b = "foo\nbaz\nbar\nquux".lines().collect::<Vec<_>>();
let differ = Differ::new(&a, &b);
for span in differ.spans() {
match span.tag {
Tag::Equal => print_lines('=', &a[span.a_start..span.a_end]),
Tag::Insert => print_lines('+', &b[span.b_start..span.b_end]),
Tag::Delete => print_lines('-', &a[span.a_start..span.a_end]),
Tag::Replace => print_lines('%', &b[span.b_start..span.b_end]),
}
}
fn print_lines(c: char, lines: &[&str]) {
for line in lines {
println!("{} {}", c, line);
}
}
Output:
= foo
+ baz
= bar
- baz
= quux
use differ::{Differ, Tag};
use std::hash::{Hash, Hasher};
#[derive(Debug, Clone)]
struct Item<'a> { // Can have any data
x: i32,
y: i32,
text: &'a str, // For this example we've decided to compare the text
}
impl<'a> Item<'a> {
fn new(x: i32, y: i32, text: &'a str) -> Item<'a> {
Item { x, y, text }
}
}
impl<'a> Hash for Item<'a> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.text.hash(state); // MUST use same data as PartialEq
}
}
impl<'a> PartialEq for Item<'a> {
fn eq(&self, other: &Item) -> bool {
self.text == other.text // MUST use same data as Hash
}
}
impl<'a> Eq for Item<'a> {}
let a = vec![
Item::new(1, 3, "quebec"),
Item::new(2, 4, "alpha"),
Item::new(3, 8, "bravo"),
Item::new(5, 9, "x-ray"),
];
let b = vec![
Item::new(3, 1, "alpha"),
Item::new(8, 3, "bravo"),
Item::new(9, 5, "yankee"),
Item::new(8, 3, "charlie"),
];
let differ = Differ::new(&a, &b);
for span in differ.spans() {
match span.tag {
Tag::Equal => (), // ignore
Tag::Insert => println!("{:?}", span),
Tag::Delete => println!("{:?}", span),
Tag::Replace => println!("{:?}", span),
}
}
Output:
Span { tag: Delete, a_start: 0, a_end: 1, b_start: 0, b_end: 0 }
Span { tag: Replace, a_start: 3, a_end: 4, b_start: 2, b_end: 4 }
To upgrade from 0.3.x to 1.x, change method calls to
spans_for_matches()
to function calls to differ::spans_for_matches()
.
Note that there are no differences between 0.4 and 1.0: the new version is because the API is now considered stable.
1.0.1 Has a bug fix from "Patrick" (ko1N).
Differ is free open source software (FOSS) licensed under the GNU General Public License version 3 (GPLv3).