TSBSoftware.TextBlock 1.0.4

TextBlock

Makes F# multiline strings work like C# Raw String Literals, or Java Text Blocks.

This project was inspired by an article related to Java Text Blocks. This functionality felt like a missing feature in the F# language, and I wanted to make it available to everyone.

Who is it for?

F# developers who would like to utilize multiline strings to format content, such as: html, xml, sql, markdown, templates, etc.

Features

TextBlock provides a robust set of tools to simplify working with multiline strings in F#:

• Automatic Indentation Stripping: Removes unwanted leading whitespace (spaces or tabs) from each line, based on the minimum indentation, ensuring clean output for formats like HTML, SQL, or Markdown.
• Newline Escaping: Supports backslash (\) at the end of a line to suppress newlines, allowing long content to be split across lines in source code without affecting the output.
• Trailing Space Preservation: Preserves trailing spaces using a pipe (|) marker at the end of a line, ideal for maintaining intentional spacing in templates or formatted text.
• Custom Indentation: Allows additional indentation with a user-defined character (default is a space) and count, enabling flexible formatting for nested or styled output.
• Embedded Newline Support: Correctly handles embedded newline characters (e.g., via Environment.NewLine), ensuring accurate rendering of dynamic content like multi-line SQL queries or email templates.
• Cross-Platform Compatibility: Uses Environment.NewLine for line endings, ensuring consistent behavior across Windows (\r\n) and other platforms (\n).

Why Use TextBlock?

Getting Started

To start using TextBlock, install the NuGet package into your project file.

dotnet add package TSBSoftware.TextBlock

Open the TextBlock namespace to use the extension method.

open TextBlock

let myText =
    """
    <div>
        <p>Hello</p>
    </div>
    """
        .TextBlock()

This will produce the following string:

<div>
    <p>Hello</p>
</div>

Without using TextBlock, there would be unwanted leading indentation because of how F# processes multiline strings:

    <div>
        <p>Hello</p>
    </div>

Additional Examples

Strings can contain embedded newline characters.

let embeddedNewlines =
    let nl = System.Environment.NewLine

    $"""
    This content has {nl}several lines
    in {nl}the text.
    """
        .TextBlock()

This will produce

This content has
several lines
in
the text.

Newlines can be escaped with a backslash.

let myText =
    """
    Hello \
    World!
    """
        .TextBlock()

This removes the newline character and combines the text into a single line:

Hello World!

Spaces at the end of each line can be preserved.

let blockedLines =
    """
    BlockLine   |
    Text        |
    """
        .TextBlock()

This will produce the following. Trailing spaces are shown as dots for clarity.

BlockLine���
Text��������

You can apply additional indentation with a specified level and an optional character (default is a space).

let someHtml =
    """
    <div>
        <p>Hello</p>
    </div>
    """
        .TextBlock(indent = 4, indentChar = '�')

This will produce the following:

����<div>
����    <p>Hello</p>
����</div>

Notes

• Repeated Application: TextBlock is designed for one-shot processing of multiline strings. Applying it multiple times (e.g., myText.TextBlock().TextBlock()) is not recommended, as it may alter indentation or formatting unexpectedly.

• Platform Newlines: Output uses Environment.NewLine, which may produce \r\n on Windows or \n on other platforms, ensuring compatibility with your target systems.

License

• License: MIT (see LICENSE for details)

Source Code

The source code and tests are available on GitHub.