rline

A native Linux GUI text editor with AI-assisted coding features, built with Rust and GTK4.

For the avoidance of doubt, this isn't meant to be a project that works for everyone out-of-the-box. It's an experiment in personalised software - the idea is that you fork it, and get your favourite vibe-coding slop generator to add the features that you want in a simple, distraction-free development environment.

Features

Editor

• Tabbed editor built on sourceview5 with tree-sitter incremental syntax highlighting
• Language auto-detection from file extension, modified-buffer indicator, close-with-unsaved-changes prompt
• Vertical split (Ctrl+) into two side-by-side editor panes with cross-pane deduplication
• Tab context menu (Close, Close All, Close Others, Close All Left/Right) and MRU cycling via Ctrl+Tab
• Find/replace overlay bar (Ctrl+F / Ctrl+H) backed by sourceview5::SearchContext
• Configurable line numbers, current-line highlight, tab width, font family, letter spacing, line height, and hinting

File Browser

• Recursive project tree with lazy loading and hidden-file support
• Single-click to open, right-click context menu for Open / Rename / Delete
• "Browse" button to pick a new project root via gtk4::FileDialog

Project Search (Ctrl+Shift+F)

• Background, cancellable full-text search across the project
• Results grouped by file with expand/collapse arrows; files with few matches auto-expand
• Skips .git, target, node_modules, and binary files

Quick Open (Ctrl+P)

• Modal fuzzy file finder using subsequence matching (up to 10,000 files indexed per project)

Git Integration

• Staged / unstaged lists with M/A/D/R/C status badges and per-file stage, unstage, discard actions
• Stage All / Unstage All bulk actions and inline commit message input
• Side-by-side diff view with hunk highlighting, opened as an editor tab
• Auto-refresh when the Git tab becomes visible; all operations run on background threads via git2

Status Bar

• Repository name and current branch
• Debounced git blame for the current cursor line (author, relative time, commit summary)

Embedded Terminal

• Tabbed vte4 terminals with a "+" button for new sessions
• Defaults to the project root (or $HOME) as the working directory
• Configurable font size

AI Inline Completion

• Fill-in-the-middle completion against any OpenAI-compatible /v1/completions endpoint
• Automatic, manual, or combined trigger modes with configurable debounce, context lines, max tokens, and temperature
• Cancels in-flight requests on new edits to avoid stale suggestions

AI Agent (Ctrl+Shift+A)

• Agentic chat panel modeled on the Cline VS Code extension, with Plan and Act modes
• Streaming SSE responses rendered as they arrive, with markdown formatting on completion
• Eleven built-in tools: read_file, write_to_file, replace_in_file, list_files, search_files, execute_command, list_code_definition_names, ask_followup_question, attempt_completion, plan_mode_respond, browser_action
• Headless-Chromium browser_action tool for launching URLs, clicking, typing, scrolling, and capturing screenshots (attached inline for multimodal models, otherwise saved to .agent-cache/screenshots/)
• Permission system: auto-approve by category (read files, edit files, safe commands, browser), with workspace-boundary enforcement and a safe-command whitelist; unsafe commands always require approval
• Token-aware context truncation with a live counter in the panel header
• Conversation persistence across sends and mode switches; "New Task" resets the context
• History saved to .agent-history/ as timestamped Markdown files
• Reads .clinerules (file or directory) and memory-bank/*.md into the system prompt
• Works with any OpenAI-compatible /v1/chat/completions server supporting tool/function calling (llama.cpp, vLLM, Ollama, etc.)

Theming

• Built-in GtkSourceView schemes plus automatic import of installed VS Code themes (converted to GtkSourceView XML)
• Rich TextMate scope resolution for UI chrome (sidebar, status bar, tabs) so the whole window matches the scheme
• Automatic light/dark text based on perceived brightness of the scheme background

Settings

Persisted as JSON at ~/.config/rline/settings.json, with three tabs:

• Editor — theme, fonts, tab width, terminal font, startup behavior, search and Ctrl+Tab options, tree-sitter toggle
• Completion — endpoint, API key, model, trigger mode, debounce, max tokens, context lines, temperature
• Agent — endpoint, API key, model, max tokens, temperature, context length, command timeout, auto-approve toggles, browser multimodal / viewport

Keyboard Shortcuts

Shortcut	Action
Ctrl+O	Open file
Ctrl+S	Save file
Ctrl+W	Close current editor tab
Ctrl+P	Quick open (fuzzy file finder)
Ctrl+F	Find in current file
Ctrl+H	Find and replace in current file
Ctrl+\	Split editor vertically
Ctrl+Tab	Cycle MRU tabs
Ctrl+Q	Quit
Ctrl+Shift+F	Focus project search
Ctrl+Shift+G	Show git panel
Ctrl+Shift+E	Show files panel
Ctrl+Shift+W	Focus terminal
Ctrl+Shift+A	Focus agent panel

Supported Languages

Tree-sitter grammars are shipped for the following languages (each is feature-gated so unused grammars can be omitted from the binary):

Language	Extensions
Rust	.rs
Python	.py, .pyi, .pyw
JavaScript	.js, .jsx, .mjs, .cjs
C	.c, .h
C++	.cpp, .cc, .cxx, .hpp, .hxx, .hh
JSON	.json
Bash	.sh, .bash, .zsh
HTML	.html, .htm
CSS	.css
Markdown	.md, .markdown
Ruby	.rb, .rake, .gemspec
YAML	.yaml, .yml
XML	.xml, .xsl, .xslt, .xsd, .svg
HAML	.haml

Files without a matching grammar still open with GtkSourceView's built-in highlighting where available.

System Dependencies

Install the required development libraries before building. A Chromium or Chrome binary must also be on PATH for the agent's browser_action tool (chromium, chromium-browser, or google-chrome).

Ubuntu / Debian

sudo apt-get install -y \
    libgtk-4-dev \
    libgtksourceview-5-dev \
    libvte-2.91-gtk4-dev \
    libgraphene-1.0-dev \
    chromium-browser

Fedora

sudo dnf install -y \
    gtk4-devel \
    gtksourceview5-devel \
    vte291-gtk4-devel \
    graphene-devel \
    chromium

Arch Linux

sudo pacman -S gtk4 gtksourceview5 vte4 graphene chromium

Building

Requires Rust 1.85 or later.

cargo build              # Debug build
cargo build --release    # Release build

Binary Pre-Requisites

If installing a pre-built binary rather than building from source:

sudo apt install libvte-2.91-gtk4-0 libgtksourceview-5-0 libgraphene-1.0-0

Running

cargo run

Development

cargo fmt --check                                          # Check formatting
cargo clippy -- -D warnings                                # Lint
cargo test --workspace                                     # Run tests
cargo fmt && cargo clippy -- -D warnings && cargo test --workspace  # Pre-commit checklist