Unicode Text Segmentation for Go

This is an implementation of the Unicode Text Segmentation specification for Go. Specifically, it currently includes only the "grapheme cluster" segmentation algorithm.

Unicode Version Support

Each major version of Unicode includes a set of tables that define how each codepoint participates in the segmentation algorithms. Therefore any caller of this library must select a specific version of Unicode to support.

To allow for each caller to make that decision separately even though multiple callers may coexist in the same program, there is a separate major release of this module for each supported major Unicode version. Therefore you can select the specific version you want by module path. For example, to use the algorithm and tables defined by Unicode version 13:

go get github.com/apparentlymart/go-textseg/v13

import (
    "github.com/apparentlymart/go-textseg/v13/textseg"
)

However, each release of Go also includes some Unicode-version-specific functionality and you may prefer to use the text segmentation definitions that are relevant to the version of Unicode that your Go runtime is using elsewhere. To enable that, this repository has a special separate module which uses the current Go runtime version to select a suitable versioned implementation automatically:

go get github.com/apparentlymart/go-textseg/autoversion

import (
    "github.com/apparentlymart/go-textseg/autoversion/textseg"
)

IMPORTANT: This "autoversion" wrapper uses Go build tags to select a go-textseg major version based on the current Go version. We use this strategy to ensure that only one version of go-textseg will be compiled into your program, but the downside is that go-textseg must be updated for each new Go release. If you use this library in your program, you will need to fetch a new version of it each time you switch to a new version of Go, even if that version of Go does not introduce a new Unicode version.

Usage

The most important function in each textseg package is ScanGraphemeClusters, which is a function compatible with the signature of bufio.Scanner in the Go standard library. Each time the Scan function is called, the function will produce one full grapheme cluster.