This is a simple library to split texts (greedily). The specific usecase I had in mind when writing this is a chat bot that can only send message of at most, say, 2000 characters. Longer texts should be split over multiple messsages.

This package requires dotNet Standard v2.1. You can install TextSplitter by installing the corresponding nuget package from here.

The library is built around three different types: ITextProvider, ITextPosition, and ITextChunk. An ITextProvider can give you an ITextPosition that represents the starting position of its text. An ITextPosition can be asked for an ITextChunk that fits in a given number of characters. This is where the meat of the library lives. Finally, an ITextChunk provides its actual length and a method to write itself to a StringWriter.

All the functions you should usually need to use are the static members of TextBuilder. They allow you to construct ITextProviders in different ways. For example:

var text = TextBuilder.Text("This is a test.");

// GetSections returns the chunks of the provider as strings, good for testing purposes.
// Each section can have at most 5 characters in this example.
CollectionAssert.AreEqual(
    new[]("This", "is a", "test."),
    text.GetSections(5)
);

To get an idea of what the functions on TextBuilder do, it might be prudent to take a look at the tests in this repository. For a more elaborate example, try this:

using static TextBuilder;

// Combine multiple texts and allow them to be separated by splits.
Separated(

    // Glue a headline to the paragraph. There can be breaks in the first and the second part
    // of the glue, but not between them.
    Glue(
        // This headline won't split anywhere, because it is atomic.
        Atomic("HEADLINE"),
        // This text will split at whitespaces. 
        Text("The paragraph.")
    ),
    // insert a mandatory linebreak here
    Atomic("\n"),

    // ensure that when any of the inner chunks is split it will still be correctly
    // wrapped in a markdown code block
    Wrap("```csharp", "```",
        // allow the code block to be split at newlines only
        SplitAt(
            c => c == '\n',
@"public class Program {
    public static void Main(string[] args) {
        Console.WriteLine(""Hello World"");
    }
}
"
        )
    )
)

Contributions are welcome as long as they are in the spirit of the library and come with some unit tests.

This project is build with the usage of the dotnet CLI in mind. Consequently, running the tests only involves cd'ing into the TextSplitter.Tests directory and running dotnet test.