Unicode Text Segmentation

Shard TextSegment implements Unicode Text Segmentation according to Unicode Standard Annex #29 (Unicode version 13.0.0) to determine the grapheme cluster boundaries of unicode text.

In Crystal, String class provides a codepoints method to return Unicode code points. However, multiple code points may be combined into one user-perceived character or what the Unicode specification calls grapheme cluster. Here are some examples:

|String|Bytes (UTF-8)|Code points |Grapheme clusters| |-|-|-|-| |Käse|6 bytes: 4b 61 cc 88 73 65|5 code points: 4b 61 308 73 65|4 clusters: [4b],[61 308],[73],[65]| |🧙‍♂️💈|17 bytes: f0 9f a7 99 e2 80 8d e2 99 82 ef b8 8f f0 9f 92 88|5 code points: 1f9d9 200d 2642 fe0f 1f488|2 cluster: [1f9d9 200d 2642 fe0f],[1f488]| |🇵🇰|8 bytes: f0 9f 87 b5 f0 9f 87 b0|2 code points: 1f1f5 1f1f0|1 cluster: [1f1f5 1f1f0]|

This shard provides a tool to iterate over these grapheme clusters. This may be used to determine the number of user-perceived characters, to split strings in their intended places, or to extract individual characters which form a unit.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     textseg:
       github: naqvis/uni_text_seg
   

2. Run shards install

Usage

require "textseg"

TextSegment.each_grapheme("🔮👍🏼!") do |cluster|
  pp cluster.codepoints
  pp cluster.positions
  pp cluster.str
  pp cluster.bytes
end

Development

To run all tests:

crystal spec

Contributing

1. Fork it (https://github.com/naqvis/uni_text_seg/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Ali Naqvi - creator and maintainer