pyreadline3: GNU Readline for Python on Windows

Warnings

• breaking pyreadline3 currently does not work with Python 3.13.0, as Python 3.13 introduced a new REPL. Even with `PYTHON_BASIC_REPL` environment variable set, history is not preserved across sessions.
  Fix: Use Python versions prior to 3.13 or monitor the pyreadline3 GitHub repository for updates and compatibility fixes for Python 3.13+.
• gotcha When managing history files with `readline.read_history_file()`, the specified history file must already exist. If it does not, a `FileNotFoundError` will be raised.
  Fix: Ensure the history file is created (e.g., `open(filename, 'w').close()`) before attempting to read from it.
• gotcha pyreadline3 is primarily developed and tested for Windows environments to provide GNU readline functionality where it's natively absent. While it may technically install on other OS, its primary benefit is on Windows, and behavior on Unix-like systems (which have a native `readline` module) might be unexpected or redundant.
  Fix: Confirm you need `pyreadline3` for your specific operating system. On Unix-like systems, the built-in `readline` module is usually sufficient.
• gotcha The Ctrl-C key binding has configurable behavior. By default, it might act as a copy operation, requiring a double-tap within a configurable time interval (`ctrl_c_tap_time_interval`) to raise a `KeyboardInterrupt`.
  Fix: Configure `allow_ctrl_c(True)` and adjust `ctrl_c_tap_time_interval(x)` in a configuration file (`pyreadlineconfig.ini`) or through `parse_and_bind` to customize Ctrl-C behavior.

Install

• pip install pyreadline3 Install stable version

Imports

• readline

  import readline

  On Windows, pyreadline3 typically patches the built-in 'readline' module, making it available as if it were the standard Unix 'readline' library.
• Readline

  from pyreadline3 import Readline

  Directly import the Readline class for explicit control or when the implicit patching of the 'readline' module is not desired or working as expected.

Quickstart

This quickstart demonstrates how pyreadline3 makes the `readline` module available and functional on Windows. After installation, `import readline` should seamlessly provide command-line editing features. The example shows a basic interactive loop with exit conditions.

import sys
# On Windows, pyreadline3 often patches sys.modules['readline']
# so standard 'import readline' works. Explicit import is also possible.
try:
    import readline
except ImportError:
    from pyreadline3 import Readline
    readline = Readline()

print("pyreadline3 is active. Try typing, using arrow keys for history, or Tab (if configured).")
print("Enter 'exit' to quit.")

while True:
    try:
        user_input = input(">>> ")
        if user_input.lower() == 'exit':
            break
        if user_input:
            print(f"You typed: {user_input}")
    except EOFError: # Ctrl+D
        print("\nExiting (Ctrl+D detected).")
        break
    except KeyboardInterrupt: # Ctrl+C
        print("\nExiting (Ctrl+C detected).")
        break