Go f-strings for VS Code

A VS Code extension that brings Python-like f-string syntax to Go through special comments.

Features

This extension allows you to write string formatting in Go using a more concise, Python-inspired f-string syntax. It automatically converts special comments into equivalent fmt.Sprintf statements.

Simply write a comment with the syntax:

// fstring result := "Hello, {name}!"

And it will automatically be converted to:

result := fmt.Sprintf("Hello, %s!", name)

The extension also ensures that the fmt package is imported when needed.

Supported Comment Styles

You can use any of the following comment styles:

• // fstring
• // fs

Assignment Types

The extension supports both := and = assignment operators:

// fstring result := "Hello, {name}!"  // Uses :=
// fstring existingVar = "Value: {value}"  // Uses =

Type Hints

You can provide formatting type hints using colon syntax:

// fstring result := "Integer: {number:d}, Float: {price:f}, String: {name:s}"

Supported type hints:

• d: Integer format (%d)
• f: Float format (%f)
• s: String format (%s)
• v: Default format (%v)
• t: Boolean format (%t)
• x: Hex format (%x)
• w: Wrapped error format (%w)

Smart Type Detection

The extension attempts to automatically detect variable types from your code when no explicit type hint is provided:

• Variables like err or ending with err/error are treated as error types (%w)
• Numeric, string, boolean and other types are detected based on declarations in your code

Escaping Braces

You can include literal braces in your strings by escaping them:

// fstring message := "Use \{variable} to show literal braces"

How It Works

• Add a comment with one of the supported prefixes followed by a variable assignment and string with placeholders in curly braces
• The extension automatically converts this to a proper Go fmt.Sprintf statement on the next line
• The conversion happens when you open Go files or make changes to them

Requirements

• VS Code version 1.98.0 or higher
• Working with Go files

Installation

From VS Code Marketplace

1. Open VS Code
2. Go to Extensions view (Ctrl+Shift+X)
3. Search for "Go f-strings"
4. Click Install

From VSIX File

1. Package the extension: npm install -g @vscode/vsce && vsce package
2. Install in VS Code:
   • From Extensions view: Click ... > Install from VSIX...
   • Or using command line: code --install-extension go-fstrings-1.0.4.vsix

From Source

1. Clone the repository
2. Run npm install
3. Press F5 to launch the extension in development mode

Known Issues

• Complex expressions inside curly braces may not work as expected
• Type detection is based on basic pattern matching and may not work for all variable declarations

License

This extension is licensed under the MIT License.