ziglyph

Unicode text processing for the Zig Programming Language.

In-Depth Articles on Unicode Processing with Zig and Ziglyph

The Unicode Processing with Zig series of articles over on ZigNEWS covers important aspects of Unicode in general and in particular how to use this library to process Unicode text.

Looking for an UTF-8 String Type?

Zigstr is a UTF-8 string type that incorporates many of Ziglyph's Unicode processing tools. You can learn more in the Zigstr repo.

Status

This is pre-1.0 software. Although breaking changes are less frequent with each minor version release, they still will occur until we reach 1.0.

Integrating Ziglyph in your Project

Zig Package Manager

In a build.zig.zon file add the following to the dependencies object. Currently only tar.gz urls are supported.

.ziglyph = .{
    .url = "https://github.com/jecolon/ziglyph/archive/<FULL COMMIT SHA>.tar.gz",
    .hash = "sha2-256 hash of the tar.gz file",
}

Then in your build.zig file add the following to the exe section for the executable where you wish to have Ziglyph available.

const ziglyph = b.dependency("ziglyph", .{
    .target = target,
    .optimize = optimize,
});
exe.addModule("ziglyph", ziglyph.module("ziglyph"));

Now in the code, you can import components like this:

const ziglyph = @import("ziglyph");
const letter = @import("ziglyph").letter; // or const letter = ziglyph.letter;
const number = @import("ziglyph").number; // or const number = ziglyph.number;

Using Zigmod

$ zigmod aq add 1/jecolon/ziglyph
$ zigmod fetch

Now in your build.zig you add this import:

const deps = @import("deps.zig");

In the exe section for the executable where you wish to have Zigstr available, add:

deps.addAllTo(exe);

Using the `ziglyph` Namespace

The ziglyph namespace provides convenient acces to the most frequently-used functions related to Unicode code points and strings.

const ziglyph = @import("ziglyph");

test "ziglyph namespace" {
    const z = 'z';
    try expect(ziglyph.isLetter(z));
    try expect(ziglyph.isAlphaNum(z));
    try expect(ziglyph.isPrint(z));
    try expect(!ziglyph.isUpper(z));
    const uz = ziglyph.toUpper(z);
    try expect(ziglyph.isUpper(uz));
    try expectEqual(uz, 'Z');

    // String toLower, toTitle, and toUpper.
    var allocator = std.testing.allocator;
    var got = try ziglyph.toLowerStr(allocator, "AbC123");
    errdefer allocator.free(got);
    try expect(std.mem.eql(u8, "abc123", got));
    allocator.free(got);

    got = try ziglyph.toUpperStr(allocator, "aBc123");
    errdefer allocator.free(got);
    try expect(std.mem.eql(u8, "ABC123", got));
    allocator.free(got);

    got = try ziglyph.toTitleStr(allocator, "thE aBc123 moVie. yes!");
    defer allocator.free(got);
    try expect(std.mem.eql(u8, "The Abc123 Movie. Yes!", got));
}

Category Namespaces

Namespaces for frequently-used Unicode General Categories are available. See ziglyph.zig for a full list of all components.

const letter = @import("ziglyph").letter;
const punct = @import("ziglyph").punct;

test "Category namespaces" {
    const z = 'z';
    try expect(letter.isletter(z));
    try expect(!letter.isUpper(z));
    try expect(!punct.ispunct(z));
    try expect(punct.ispunct('!'));
    const uz = letter.toUpper(z);
    try expect(letter.isUpper(uz));
    try expectEqual(uz, 'Z');
}

Normalization

In addition to the basic functions to detect and convert code point case, the Normalizer struct provides code point and string normalization methods. All normalization forms are supported (NFC, NFKC, NFD, NFKD.).

const Normalizer = @import("ziglyph").Normalizer;

test "normalizeTo" {
    var allocator = std.testing.allocator;
    var normalizer = try Normalizer.init(allocator);
    defer normalizer.deinit();

    // Canonical Composition (NFC)
    const input_nfc = "Complex char: \u{03D2}\u{0301}";
    const want_nfc = "Complex char: \u{03D3}";
    var got_nfc = try normalizer.nfc(allocator, input_nfc);
    defer got_nfc.deinit();
    try testing.expectEqualSlices(u8, want_nfc, got_nfc.slice);

    // Compatibility Composition (NFKC)
    const input_nfkc = "Complex char: \u{03A5}\u{0301}";
    const want_nfkc = "Complex char: \u{038E}";
    var got_nfkc = try normalizer.nfkc(allocator, input_nfkc);
    defer got_nfkc.deinit();
    try testing.expectEqualSlices(u8, want_nfkc, got_nfkc.slice);

    // Canonical Decomposition (NFD)
    const input_nfd = "Complex char: \u{03D3}";
    const want_nfd = "Complex char: \u{03D2}\u{0301}";
    var got_nfd = try normalizer.nfd(allocator, input_nfd);
    defer got_nfd.deinit();
    try testing.expectEqualSlices(u8, want_nfd, got_nfd.slice);

    // Compatibility Decomposition (NFKD)
    const input_nfkd = "Complex char: \u{03D3}";
    const want_nfkd = "Complex char: \u{03A5}\u{0301}";
    var got_nfkd = try normalizer.nfkd(allocator, input_nfkd);
    defer got_nfkd.deinit();
    try testing.expectEqualSlices(u8, want_nfkd, got_nfkd.slice);

    // String comparisons.
    try testing.expect(try normalizer.eql(allocator, "foé", "foe\u{0301}"));
    try testing.expect(try normalizer.eql(allocator, "foϓ", "fo\u{03D2}\u{0301}"));
    try testing.expect(try normalizer.eqlCaseless(allocator, "Foϓ", "fo\u{03D2}\u{0301}"));
    try testing.expect(try normalizer.eqlCaseless(allocator, "FOÉ", "foe\u{0301}")); // foÉ == foé
    // Note: eqlIdentifiers is not a method, it's just a function in the Normalizer namespace.
    try testing.expect(try Normalizer.eqlIdentifiers(allocator, "Foé", "foé")); // Unicode Identifiers caseless match.
}

Collation (String Ordering)

One of the most common operations required by string processing is sorting and ordering comparisons. The Unicode Collation Algorithm was developed to attend this area of string processing. The Collator struct implements the algorithm, allowing for proper sorting and order comparison of Unicode strings.

const Collator = @import("ziglyph").Collator;

test "Collation" {
    var c = try Collator.init(std.testing.allocator);
    defer c.deinit();

    // Ascending / descending sort
    var strings = [_][]const u8{ "def", "xyz", "abc" };
    var want = [_][]const u8{ "abc", "def", "xyz" };

    std.mem.sort([]const u8, &strings, c, Collator.ascending);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);

    want = [_][]const u8{ "xyz", "def", "abc" };
    std.mem.sort([]const u8, &strings, c, Collator.descending);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);

    // Caseless sorting
    strings = [_][]const u8{ "def", "Abc", "abc" };
    want = [_][]const u8{ "Abc", "abc", "def" };

    std.mem.sort([]const u8, &strings, c, Collator.ascendingCaseless);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);

    want = [_][]const u8{ "def", "Abc", "abc" };
    std.mem.sort([]const u8, &strings, c, Collator.descendingCaseless);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);

    // Caseless / markless sorting
    strings = [_][]const u8{ "ábc", "Abc", "abc" };
    want = [_][]const u8{ "ábc", "Abc", "abc" };

    std.mem.sort([]const u8, &strings, c, Collator.ascendingBase);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);

    std.mem.sort([]const u8, &strings, c, Collator.descendingBase);
    try std.testing.expectEqualSlices([]const u8, &want, &strings);
}

Tailoring with allkeys.txt

You can tailor the sorting of Unicode text by modifying the sort element weights found in allkeys.txt.gz. Uncompress the file with gunzip and modify it as needed. To prepare the file for use with Ziglyph, you need to process and compress the data as follows:

$ cd <path to ziglyph src>/src 
$ zig build-exe -D ReleaseSafe akcompress.zig 
$ mkdir <path to temporary dir>
$ mv akcompress <path to temporary dir>/
$ cp data/uca/allkeys.txt.gz <path to temporary dir>/
$ cp data/uca/allkeys-diffs.txt.gz data/uca/allkeys-diffs.txt.gz.bak
$ cd <path to temporary dir>
$ gunzip allkeys.txt.gz 
$ vim allkeys.txt # <- Modify the file
$ ./akcompress 
$ gzip -9 allkeys-diffs.txt 
$ cp allkeys-diffs.txt.gz <path to ziglyph source>/src/data/uca/

Now when you use the Collator it will reflect the sort element weights you modified.

Text Segmentation (Grapheme Clusters, Words, Sentences)

Ziglyph has iterators to traverse text as Grapheme Clusters (what most people recognize as characters), Words, and Sentences. All of these text segmentation functions adhere to the Unicode Text Segmentation rules, which may surprise you in terms of what's included and excluded at each break point. Test before assuming any results! There are also non-allocating compile-time versions for use with string literals or embedded files. Note that for compile-time versions, you may need to increase the compile-time branch evaluation quota via @setEvalBranchQuota.

const Grapheme = @import("ziglyph").Grapheme;
const GraphemeIterator = Grapheme.GraphemeIterator;
const SentenceIterator = Sentence.SentenceIterator;
const ComptimeSentenceIterator = Sentence.ComptimeSentenceIterator;
const Word = @import("ziglyph").Word;
const WordIterator = Word.WordIterator;

test "GraphemeIterator" {
    const input = "H\u{0065}\u{0301}llo";
    var iter = try GraphemeIterator.init(input);

    const want = &[_][]const u8{ "H", "\u{0065}\u{0301}", "l", "l", "o" };

    var i: usize = 0;
    while (iter.next()) |grapheme| : (i += 1) {
        try testing.expect(grapheme.eql(want[i]));
    }

    // Need your grapheme clusters at compile time?
    comptime {
        var ct_iter = try GraphemeIterator.init(input);
        var j = 0;
        while (ct_iter.next()) |grapheme| : (j += 1) {
            try testing.expect(grapheme.eql(want[j]));
        }
    }
}

test "SentenceIterator" {
    var allocator = std.testing.allocator;
    const input =
        \\("Go.") ("He said.")
    ;
    var iter = try SentenceIterator.init(allocator, input);
    defer iter.deinit();

    // Note the space after the closing right parenthesis is included as part
    // of the first sentence.
    const s1 =
        \\("Go.") 
    ;
    const s2 =
        \\("He said.")
    ;
    const want = &[_][]const u8{ s1, s2 };

    var i: usize = 0;
    while (iter.next()) |sentence| : (i += 1) {
        try testing.expectEqualStrings(sentence.bytes, want[i]);
    }

    // Need your sentences at compile time?
    @setEvalBranchQuota(2_000);

    comptime var ct_iter = ComptimeSentenceIterator(input){};
    const n = comptime ct_iter.count();
    var sentences: [n]Sentence = undefined;
    comptime {
        var ct_i: usize = 0;
        while (ct_iter.next()) |sentence| : (ct_i += 1) {
            sentences[ct_i] = sentence;
        }
    }

    for (sentences) |sentence, j| {
        try testing.expect(sentence.eql(want[j]));
    }
}

test "WordIterator" {
    const input = "The (quick) fox. Fast! ";
    var iter = try WordIterator.init(input);

    const want = &[_][]const u8{ "The", " ", "(", "quick", ")", " ", "fox", ".", " ", "Fast", "!", " " };

    var i: usize = 0;
    while (iter.next()) |word| : (i += 1) {
        try testing.expectEqualStrings(word.bytes, want[i]);
    }

    // Need your words at compile time?
    @setEvalBranchQuota(2_000);

    comptime {
        var ct_iter = try WordIterator.init(input);
        var j = 0;
        while (ct_iter.next()) |word| : (j += 1) {
            try testing.expect(word.eql(want[j]));
        }
    }
}

Code Point and String Display Width

When working with environments in which text is rendered in a fixed-width font, such as terminal emulators, it's necessary to know how many cells (or columns) a particular code point or string will occupy. The display_width namespace provides functions to do just that.

const dw = @import("ziglyph").display_width;

test "Code point / string widths" {
    // The width methods take a second parameter of value .half or .full to determine the width of 
    // ambiguous code points as per the Unicode standard. .half is the most common case.

    // Note that codePointWidth returns an i3 because code points like backspace have width -1.
    try expectEqual(dw.codePointWidth('é', .half), 1);
    try expectEqual(dw.codePointWidth('😊', .half), 2);
    try expectEqual(dw.codePointWidth('统', .half), 2);

    var allocator = std.testing.allocator;

    // strWidth returns usize because it can never be negative, regardless of the code points it contains.
    try expectEqual(try dw.strWidth("Hello\r\n", .half), 5);
    try expectEqual(try dw.strWidth("\u{1F476}\u{1F3FF}\u{0308}\u{200D}\u{1F476}\u{1F3FF}", .half), 2);
    try expectEqual(try dw.strWidth("Héllo 🇵🇷", .half), 8);
    try expectEqual(try dw.strWidth("\u{26A1}\u{FE0E}", .half), 1); // Text sequence
    try expectEqual(try dw.strWidth("\u{26A1}\u{FE0F}", .half), 2); // Presentation sequence

    // padLeft, center, padRight
    const right_aligned = try dw.padLeft(allocator, "w😊w", 10, "-");
    defer allocator.free(right_aligned);
    try expectEqualSlices(u8, "------w😊w", right_aligned);

    const centered = try dw.center(allocator, "w😊w", 10, "-");
    defer allocator.free(centered);
    try expectEqualSlices(u8, "---w😊w---", centered);

    const left_aligned = try dw.padRight(allocator, "w😊w", 10, "-");
    defer allocator.free(left_aligned);
    try expectEqualSlices(u8, "w😊w------", left_aligned);
}

Word Wrap

If you need to wrap a string to a specific number of columns according to Unicode Word boundaries and display width, you can use the display_width struct's wrap function for this. You can also specify a threshold value indicating how close a word boundary can be to the column limit and trigger a line break.

const dw = @import("ziglyph").display_width;

test "display_width wrap" {
    var allocator = testing.allocator;
    var input = "The quick brown fox\r\njumped over the lazy dog!";
    var got = try dw.wrap(allocator, input, 10, 3);
    defer allocator.free(got);
    var want = "The quick\n brown \nfox jumped\n over the\n lazy dog\n!";
    try testing.expectEqualStrings(want, got);
}

jecolon/ziglyph

jecolon

Reviews

Repository Details

ziglyph

In-Depth Articles on Unicode Processing with Zig and Ziglyph

Looking for an UTF-8 String Type?

Status

Integrating Ziglyph in your Project

Zig Package Manager

Using Zigmod

Using the `ziglyph` Namespace

Category Namespaces

Normalization

Collation (String Ordering)

Tailoring with allkeys.txt

Text Segmentation (Grapheme Clusters, Words, Sentences)

Code Point and String Display Width

Word Wrap

More Repositories

jecolon/ziglyph

jecolon

Reviews

Repository Details

ziglyph

In-Depth Articles on Unicode Processing with Zig and Ziglyph

Looking for an UTF-8 String Type?

Status

Integrating Ziglyph in your Project

Zig Package Manager

Using Zigmod

Using the ziglyph Namespace

Category Namespaces

Normalization

Collation (String Ordering)

Tailoring with allkeys.txt

Text Segmentation (Grapheme Clusters, Words, Sentences)

Code Point and String Display Width

Word Wrap

More Repositories

Using the `ziglyph` Namespace