Crate lexicmp

This is a library to compare and sort strings (or file paths) lexicographically. This means that non-ASCII characters such as á or ß are treated like their closest ASCII character: á is treated as a, ß is treated as ss, etc.

Lexical comparisons are case-insensitive. Alphanumeric characters are sorted after all other characters (punctuation, whitespace, special characters, emojis, …).

It is possible to enable natural sorting, which also handles ASCII numbers. For example, 50 is less than 100 with natural sorting turned on. It’s also possible to skip characters that aren’t alphanumeric, so e.g. f-5 is next to f5.

If different strings have the same ASCII representation (e.g. "Foo" and "fóò"), it falls back to the default method from the standard library, so sorting is deterministic.

NOTE: This crate doesn't attempt to be correct for every locale, but it should work reasonably well for a wide range of locales, while providing excellent performance.

Usage

To sort strings or paths, you can use the StringSort or PathSort trait:

use lexicmp::{StringSort, natural_lexical_cmp};

let mut strings = vec!["ß", "é", "100", "hello", "world", "50", ".", "B!"];
strings.string_sort_unstable(natural_lexical_cmp);

assert_eq!(&strings, &[".", "50", "100", "B!", "é", "hello", "ß", "world"]);

There are eight comparison functions:

Function	lexico­graphical	natural	skips non-alphanumeric chars
cmp
only_alnum_cmp			yes
lexical_cmp	yes
lexical_only_alnum_cmp	yes		yes
natural_cmp		yes
natural_only_alnum_cmp		yes	yes
natural_lexical_cmp	yes	yes
natural_lexical_­only_alnum_cmp	yes	yes	yes

Note that only the functions that sort lexicographically are case insensitive.

Modules

• iter
  Iterators to transliterate Unicode to ASCII. Note that only alphanumeric characters are transliterated, and not all of them are supported.

Traits

• StringSort
  A trait to sort strings. This is a convenient wrapper for the standard library sort functions.

Functions

• cmp
  Compares strings (not lexicographically or naturally, doesn’t skip non-alphanumeric characters)
• lexical_cmp
  Compares strings lexicographically
• lexical_only_alnum_cmp
  Compares strings lexicographically, skipping non-alphanumeric characters
• natural_cmp
  Compares strings naturally
• natural_lexical_cmp
  Compares strings naturally and lexicographically
• natural_lexical_only_alnum_cmp
  Compares strings naturally and lexicographically, skipping non-alphanumeric characters
• natural_only_alnum_cmp
  Compares strings naturally, skipping non-alphanumeric characters
• only_alnum_cmp
  Compares strings, skipping non-alphanumeric characters