github.com/ispapp/psshclient/pkg/codeditor

codeditor

A powerful, customizable code editor widget for Fyne applications with syntax highlighting and VS Code-style theme support.

Features

• Syntax Highlighting: Support for multiple programming languages including Go, Python, JavaScript, Java, C/C++
• VS Code-Style Themes: Built-in themes (Dark, Light, VS Code Dark, Monokai) with JSON theme loading support
• Customizable: Font size, tab size, line numbers, and more
• Keyboard Navigation: Full cursor movement, text editing, and selection support
• Extensible: Easy to add new languages and themes

Installation

go get github.com/ispapp/psshclient/pkg/codeditor

Quick Start

package main

import (
    "fyne.io/fyne/v2/app"
    editor "github.com/ispapp/psshclient/pkg/codeditor"
)

func main() {
    myApp := app.New()
    myWindow := myApp.NewWindow("Code Editor")
    
    // Create a new code editor
    codeEditor := editor.NewScriptEditor()
    codeEditor.SetLanguage("go")
    codeEditor.SetContent(`package main

import "fmt"

func main() {
    fmt.Println("Hello, World!")
}`)
    
    myWindow.SetContent(codeEditor)
    myWindow.ShowAndRun()
}

API Reference

Creating an Editor

// Create a new editor with default settings
editor := NewScriptEditor()

// Create with specific language and theme
editor := CreateCodeEditor("python", GetVSCodeDarkTheme())

// Create with initial content
editor := CreateCodeEditorWithContent(code, "go", GetDefaultTheme())

Content Management

// Set and get content
editor.SetContent("your code here")
content := editor.GetContent()

// Listen for changes
editor.SetOnChanged(func(content string) {
    // Handle content changes
    fmt.Println("Content changed:", len(content), "characters")
})

Language Support

// Set programming language for syntax highlighting
editor.SetLanguage("go")        // Go
editor.SetLanguage("python")    // Python
editor.SetLanguage("javascript") // JavaScript
editor.SetLanguage("java")      // Java
editor.SetLanguage("c")         // C
editor.SetLanguage("cpp")       // C++

// Get current language
language := editor.GetLanguage()

Theme Customization

// Use built-in themes
editor.SetTheme(GetDefaultTheme())    // Dark theme
editor.SetTheme(GetLightTheme())      // Light theme
editor.SetTheme(GetVSCodeDarkTheme()) // VS Code Dark
editor.SetTheme(GetMonokaiTheme())    // Monokai

// Load theme from JSON file
theme, err := LoadThemeFromJSON("my-theme.json")
if err == nil {
    editor.SetTheme(theme)
}

Appearance Settings

// Font size
editor.SetFontSize(14.0)
size := editor.GetFontSize()

// Tab size
editor.SetTabSize(4)
tabSize := editor.GetTabSize()

// Line numbers
editor.SetShowLineNumbers(true)
showLines := editor.GetShowLineNumbers()

Theme Format

Themes can be defined in JSON format:

{
  "name": "My Custom Theme",
  "background": "#1e1e1e",
  "foreground": "#d4d4d4",
  "tokenColors": {
    "keyword": "#569cd6",
    "string": "#ce9178",
    "comment": "#6a9955",
    "number": "#b5cea8",
    "operator": "#d4d4d4",
    "identifier": "#9cdcfe",
    "function": "#dcdcaa",
    "type": "#4ec9b0",
    "plain": "#d4d4d4"
  }
}

Saving Themes

// Save a theme to JSON file
theme := GetMonokaiTheme()
err := SaveThemeToJSON(theme, "monokai-theme.json")

Supported Languages

• Go: Full syntax highlighting with keywords, types, functions, and more
• Python: Support for Python 3 syntax including decorators, f-strings, and async/await
• JavaScript: ES6+ support with classes, arrow functions, template literals
• Java: Complete Java syntax highlighting
• C/C++: Support for both C and C++ with preprocessor directives
• Generic: Basic highlighting for unknown languages

Keyboard Controls

• Arrow Keys: Navigate cursor
• Home/End: Move to line start/end
• Backspace/Delete: Delete characters
• Tab: Insert spaces (configurable tab size)
• Enter: Insert new line

Examples

See the example.go file for a complete demonstration including:

• Theme switching
• Language selection
• Font size adjustment
• Line number toggle
• Different code samples

Extending the Editor

Adding New Languages

• Add language-specific rules in lexer.go
• Create a new initialize[Language]Rules() method
• Add the language to the switch statement in initializeRules()

Creating Custom Themes

• Create a new Theme struct with your colors
• Use SaveThemeToJSON() to export as JSON
• Load with LoadThemeFromJSON() for reuse

Architecture

The widget follows Fyne's architecture patterns:

• ScriptEditor: Main widget implementing fyne.Widget
• scriptEditorRenderer: Custom renderer implementing fyne.WidgetRenderer
• Lexer: Tokenizes code for syntax highlighting
• Theme: Defines colors for different token types

Contributing

• Fork the repository
• Create a feature branch
• Add tests for new functionality
• Submit a pull request

License

This project is licensed under the same license as the parent project.