fce-enhanced

An enhanced Flet CodeEditor control with file I/O, search/replace, syntax highlighting, and theme selection.

Built on top of flet-code-editor, adding a full-featured editing experience you can drop into any Flet app or run standalone. This project was created to explore and showcase what's possible with Flet — building a desktop-quality code editor entirely in Python.

Install

pip install fce-enhanced

Or with uv:

uv add fce-enhanced

Development setup

git clone https://github.com/oktl/flet-fce-enhanced.git
cd flet-fce-enhanced
uv sync
source .venv/bin/activate
pre-commit install  # optional, for development

Usage

Run as a standalone app

uvx fce-enhanced                     # open with an empty editor
uvx fce-enhanced path/to/file.py     # open a specific file on launch

During development:

flet run src/fce_enhanced/editor.py                     # open with an empty editor
flet run src/fce_enhanced/editor.py path/to/file.py     # open a specific file on launch

Embed in your own Flet app

EnhancedCodeEditor is a Flet declarative component (@ft.component). Render it with page.render(...) rather than page.add(...).

Minimal example

import flet as ft
from fce_enhanced import EnhancedCodeEditor


def main(page: ft.Page):
    page.title = "My Editor"
    page.render(lambda: EnhancedCodeEditor(expand=True))


ft.run(main)

With configuration

import flet as ft
import flet_code_editor as fce
from fce_enhanced import EnhancedCodeEditor


def main(page: ft.Page):
    page.title = "My Editor"

    def on_title_change(display_path, name, is_dirty):
        page.title = f"{name}{'*' if is_dirty else ''} — My Editor"

    page.render(
        lambda: EnhancedCodeEditor(
            language=fce.CodeLanguage.JAVASCRIPT,
            value="console.log('hello');",
            code_theme=fce.CodeTheme.MONOKAI,
            on_title_change=on_title_change,
            ruff_on_save=False,  # disable ruff (only applies to Python files)
            expand=True,
        )
    )


ft.run(main)

Driving the editor from code

Because a component has no instance to call methods on, pass an EditorHandle to drive it imperatively (open a file, save, etc.) and read its live state:

import sys
import flet as ft
from fce_enhanced import EditorHandle, EnhancedCodeEditor


def main(page: ft.Page):
    handle = EditorHandle()
    initial = sys.argv[1] if len(sys.argv) > 1 else None
    page.render(
        lambda: EnhancedCodeEditor(
            expand=True, handle=handle, initial_path=initial
        )
    )
    # handle.open_path("/path/to/file"), handle.save(), handle.save_as(),
    # handle.close(); read handle.value / handle.dirty / handle.current_path

ft.run(main)

initial_path opens a file automatically on mount — the simplest way to load a file at startup without touching the handle.

save_path is the opposite: it seeds the save target without reading from disk, so the content you pass in value stays on screen and Save writes to a path that need not exist yet. Use it when the buffer comes from somewhere other than the filesystem.

Constructor parameters

Driving via EditorHandle

Pass an EditorHandle instance and the component populates it on every render:

handle.open_path("/path/to/file")  # load a file (no dialog)
handle.save()                      # save to current path
handle.save_as()                   # save-as dialog
handle.close()                     # close current file
handle.revert()                    # revert to last saved content (confirms)

handle.open_search(with_replace=True)  # open the find/replace bar
handle.close_search()
handle.goto_line()                 # go-to-line dialog
handle.command_palette()           # command palette
handle.show_help()                 # help dialog

handle.toggle_diff()               # show/hide the diff pane
handle.toggle_read_only()
handle.toggle_gutter()
handle.change_font_size(+1)        # or -1
handle.set_language(fce.CodeLanguage.PYTHON)  # set directly
handle.choose_language()           # or open the language picker

handle.value          # current editor content (str)
handle.current_path   # path of open file, or None
handle.dirty          # True if there are unsaved changes
handle.search_open    # True while the find/replace bar is shown

Every action is safe to call from an embedder's own keyboard handler — pair it with register_keyboard_shortcuts=False to own the key bindings yourself.

Other public exports

The package also exports these utilities from fce_enhanced:

Features

• File operations — Open, Save, Save As, Close, and Revert to Saved with unsaved-changes confirmation
• Native file dialogs — AppleScript dialogs on macOS (with extension filtering), Flet's built-in FilePicker on other platforms
• Search & Replace — Find toolbar with match counting, case sensitivity toggle, whole word matching, prev/next navigation (Enter navigates to next match), Replace and Replace All
• Command Palette — Searchable list of all available commands; type to filter (Cmd+Shift+P / Ctrl+Shift+P)
• Theme Selector — 80+ built-in syntax highlighting themes via a searchable dialog (type to filter)
• Go to Line — Jump to a specific line number (Cmd+G / Ctrl+G)
• Read-Only Mode — Toggle editing lock (Cmd+L / Ctrl+L)
• Font Size Controls — Increase/decrease font size (Cmd+= / Cmd+-)
• Language Selector — Choose syntax highlighting language from a searchable dialog (type to filter); auto-detected on file open, and Save As defaults to the matching file extension
• Language Detection — Automatic syntax highlighting for 40+ file extensions
• Dirty-File Tracking — Visual indicator for unsaved changes
• Diff Pane — Toggleable unified diff view showing changes since last save, with green/red syntax coloring (Cmd+D / Ctrl+D)
• Gutter Toggle — Show or hide the line-number gutter (Shift+Cmd+G / Ctrl+Shift+G)
• Ruff on Save — Auto-runs ruff check --fix and ruff format on .py files; silently skips if ruff is not installed (no error). Remaining lint warnings are shown in a snackbar, and the editor auto-reloads the formatted content. Toggleable from the toolbar
• Status Bar — Line, column, language, and selection info

Keyboard shortcuts

Contributing

Contributions are welcome! See CONTRIBUTING.md for guidelines.

License

MIT

Development

Code style is enforced with ruff via pre-commit hooks:

pre-commit run --all-files

Run tests:

pytest

Built With

• Flet — Build multi-platform apps in Python powered by Flutter
• flet-code-editor — Code editor control for Flet with syntax highlighting
• ruff — Fast Python linter and formatter