File: lib.rs

package info (click to toggle)
rust-difference 2.0.0-1
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 312 kB
  • sloc: makefile: 2
file content (334 lines) | stat: -rw-r--r-- 10,093 bytes parent folder | download | duplicates (11)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
//! Functions to find the difference between two texts (strings).
//! Usage
//! ----------
//!
//! Add the following to your `Cargo.toml`:
//!
//! ```toml
//! [dependencies]
//! difference = "2.0"
//! ```
//!
//! Now you can use the crate in your code
//! ```ignore
//! extern crate difference;
//! ```
//!
//! ## Examples
//!
//! See [Examples.md](Examples.md) for more examples.
//!
//! ```rust
//! use difference::{Difference, Changeset};
//!
//! let changeset = Changeset::new("test", "tent", "");
//!
//! assert_eq!(changeset.diffs, vec![
//!   Difference::Same("te".to_string()),
//!   Difference::Rem("s".to_string()),
//!   Difference::Add("n".to_string()),
//!   Difference::Same("t".to_string())
//! ]);
//! ```

#![crate_name = "difference"]
#![doc(html_root_url = "http://docs.rs/difference")]
#![deny(missing_docs)]
#![deny(warnings)]

mod lcs;
mod merge;
mod display;

use lcs::lcs;
use merge::merge;

/// Defines the contents of a changeset
/// Changesets will be delivered in order of appearance in the original string
/// Sequences of the same kind will be grouped into one Difference
#[derive(PartialEq, Debug)]
pub enum Difference {
    /// Sequences that are the same
    Same(String),
    /// Sequences that are an addition (don't appear in the first string)
    Add(String),
    /// Sequences that are a removal (don't appear in the second string)
    Rem(String),
}

/// The information about a full changeset
pub struct Changeset {
    /// An ordered vector of `Difference` objects, coresponding
    /// to the differences within the text
    pub diffs: Vec<Difference>,
    /// The split used when creating the `Changeset`
    /// Common splits are `""` for char-level, `" "` for word-level and `"\n"` for line-level.
    pub split: String,
    /// The edit distance of the `Changeset`
    pub distance: i32,
}

impl Changeset {
    /// Calculates the edit distance and the changeset for two given strings.
    /// The first string is assumed to be the "original", the second to be an
    /// edited version of the first. The third parameter specifies how to split
    /// the input strings, leading to a more or less exact comparison.
    ///
    /// Common splits are `""` for char-level, `" "` for word-level and `"\n"` for line-level.
    ///
    /// Outputs the edit distance (how much the two strings differ) and a "changeset", that is
    /// a `Vec` containing `Difference`s.
    ///
    /// # Examples
    ///
    /// ```
    /// use difference::{Changeset, Difference};
    ///
    /// let changeset = Changeset::new("test", "tent", "");
    ///
    /// assert_eq!(changeset.diffs, vec![
    ///     Difference::Same("te".to_string()),
    ///     Difference::Rem("s".to_string()),
    ///     Difference::Add("n".to_string()),
    ///     Difference::Same("t".to_string())
    /// ]);
    /// ```
    pub fn new(orig: &str, edit: &str, split: &str) -> Changeset {
        let (dist, common) = lcs(orig, edit, split);
        Changeset {
            diffs: merge(orig, edit, &common, split),
            split: split.to_string(),
            distance: dist,
        }
    }
}

/// **This function is deprecated, please use `Changeset::new` instead**
///
/// Calculates the edit distance and the changeset for two given strings.
/// The first string is assumed to be the "original", the second to be an
/// edited version of the first. The third parameter specifies how to split
/// the input strings, leading to a more or less exact comparison.
///
/// Common splits are `""` for char-level, `" "` for word-level and `"\n"` for line-level.
///
/// Outputs the edit distance (how much the two strings differ) and a "changeset", that is
/// a `Vec` containing `Difference`s.
///
/// # Examples
///
/// ```
/// use difference::diff;
/// use difference::Difference;
///
/// let (dist, changeset) = diff("test", "tent", "");
///
/// assert_eq!(changeset, vec![
///     Difference::Same("te".to_string()),
///     Difference::Rem("s".to_string()),
///     Difference::Add("n".to_string()),
///     Difference::Same("t".to_string())
/// ]);
/// ```
#[deprecated(since = "1.0.0", note = "please use `Changeset::new` instead")]
pub fn diff(orig: &str, edit: &str, split: &str) -> (i32, Vec<Difference>) {
    let ch = Changeset::new(orig, edit, split);
    (ch.distance, ch.diffs)
}

/// Assert the difference between two strings. Works like diff, but takes
/// a fourth parameter that is the expected edit distance (e.g. 0 if you want to
/// test for equality).
///
/// To include this macro use:
///
/// ```
/// #[macro_use(assert_diff)]
/// extern crate difference;
/// # fn main() { }
/// ```
///
/// Remember that edit distance might not be equal to your understanding of difference,
/// for example the words "Rust" and "Dust" have an edit distance of 2 because two changes (a
/// removal and an addition) are required to make them look the same.
///
/// Will print an error with a colorful diff in case of failure.
#[macro_export]
macro_rules! assert_diff {
    ($orig:expr , $edit:expr, $split: expr, $expected: expr) => ({
        let orig = $orig;
        let edit = $edit;

        let changeset = $crate::Changeset::new(orig, edit, &($split));
        if changeset.distance != $expected {
            println!("{}", changeset);
            panic!("assertion failed: edit distance between {:?} and {:?} is {} and not {}, see \
                    diffset above",
                   orig,
                   edit,
                   changeset.distance,
                   &($expected))
        }
    })
}

/// **This function is deprecated, `Changeset` now implements the `Display` trait instead**
///
/// Prints a colorful visual representation of the diff.
/// This is just a convenience function for those who want quick results.
///
/// I recommend checking out the examples on how to build your
/// own diff output.
/// # Examples
///
/// ```
/// use difference::print_diff;
/// print_diff("Diffs are awesome", "Diffs are cool", " ");
/// ```
#[deprecated(since = "1.0.0", note = "`Changeset` now implements the `Display` trait instead")]
pub fn print_diff(orig: &str, edit: &str, split: &str) {
    let ch = Changeset::new(orig, edit, split);
    println!("{}", ch);
}

#[test]
fn test_diff() {
    let text1 = "Roses are red, violets are blue,\n\
                 I wrote this library,\n\
                 just for you.\n\
                 (It's true).";

    let text2 = "Roses are red, violets are blue,\n\
                 I wrote this documentation,\n\
                 just for you.\n\
                 (It's quite true).";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(changeset.distance, 4);

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Same("Roses are red, violets are blue,".to_string()),
            Difference::Rem("I wrote this library,".to_string()),
            Difference::Add("I wrote this documentation,".to_string()),
            Difference::Same("just for you.".to_string()),
            Difference::Rem("(It's true).".to_string()),
            Difference::Add("(It's quite true).".to_string()),
        ]
    );
}

#[test]
fn test_diff_brief() {
    let text1 = "Hello\nworld";
    let text2 = "Ola\nmundo";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Rem("Hello\nworld".to_string()),
            Difference::Add("Ola\nmundo".to_string()),
        ]
    );
}

#[test]
fn test_diff_smaller_line_count_on_left() {
    let text1 = "Hello\nworld";
    let text2 = "Ola\nworld\nHow is it\ngoing?";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Rem("Hello".to_string()),
            Difference::Add("Ola".to_string()),
            Difference::Same("world".to_string()),
            Difference::Add("How is it\ngoing?".to_string()),
        ]
    );
}

#[test]
fn test_diff_smaller_line_count_on_right() {
    let text1 = "Hello\nworld\nWhat a \nbeautiful\nday!";
    let text2 = "Ola\nworld";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Rem("Hello".to_string()),
            Difference::Add("Ola".to_string()),
            Difference::Same("world".to_string()),
            Difference::Rem("What a \nbeautiful\nday!".to_string()),
        ]
    );
}

#[test]
fn test_diff_similar_text_with_smaller_line_count_on_right() {
    let text1 = "Hello\nworld\nWhat a \nbeautiful\nday!";
    let text2 = "Hello\nwoRLd";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Same("Hello".to_string()),
            Difference::Rem("world\nWhat a \nbeautiful\nday!".to_string()),
            Difference::Add("woRLd".to_string()),
        ]
    );
}

#[test]
fn test_diff_similar_text_with_similar_line_count() {
    let text1 = "Hello\nworld\nWhat a \nbeautiful\nday!";
    let text2 = "Hello\nwoRLd\nbeautiful";

    let changeset = Changeset::new(text1, text2, "\n");

    assert_eq!(
        changeset.diffs,
        vec![
            Difference::Same("Hello".to_string()),
            Difference::Rem("world\nWhat a ".to_string()),
            Difference::Add("woRLd".to_string()),
            Difference::Same("beautiful".to_string()),
            Difference::Rem("day!".to_string()),
        ]
    );
}

#[test]
#[should_panic]
fn test_assert_diff_panic() {
    let text1 = "Roses are red, violets are blue,\n\
                 I wrote this library,\n\
                 just for you.\n\
                 (It's true).";

    let text2 = "Roses are red, violets are blue,\n\
                 I wrote this documentation,\n\
                 just for you.\n\
                 (It's quite true).";

    assert_diff!(text1, text2, "\n'", 0);
}

#[test]
fn test_assert_diff() {
    let text1 = "Roses are red, violets are blue";

    let text2 = "Roses are green, violets are blue";

    assert_diff!(text1, text2, " ", 2);
}