readline

GNU readline support for Python on platforms without readline. This module provides Python bindings to the GNU readline library, enabling command-line editing, history management, and tab completion functionality for interactive Python sessions.

Package Information

• Package Name: readline
• Package Type: pypi
• Language: Python (C Extension)
• Installation: pip install readline
• Version: 2.6.4

Core Imports

import readline

Basic Usage

import readline

# Configure readline
readline.parse_and_bind('tab: complete')  # Enable tab completion
readline.parse_and_bind('set editing-mode vi')  # Set vi editing mode

# Set up history
readline.read_history_file()  # Load history from ~/.history
readline.set_history_length(1000)  # Limit history to 1000 entries

# Set up completion
def completer(text, state):
    options = ['hello', 'help', 'history', 'home']
    matches = [opt for opt in options if opt.startswith(text)]
    return matches[state] if state < len(matches) else None

readline.set_completer(completer)
readline.set_completer_delims(' \t\n')

# Interactive input with readline features
user_input = input("Enter command: ")  # Now has history, completion, editing

# Save history when done
readline.write_history_file()

Architecture

The readline module provides a Python interface to GNU readline's command-line editing capabilities:

• Configuration: Parse readline init files and configure behavior
• History Management: Persistent command history with file I/O and manipulation
• Line Editing: Buffer access and text insertion for command-line editing
• Tab Completion: Customizable completion system with hooks and delimiters
• Event Hooks: Startup, pre-input, and display hooks for advanced customization

This module automatically integrates with Python's input() function, providing enhanced command-line editing for interactive sessions.

Capabilities

Configuration and Initialization

Core configuration functions for setting up readline behavior, parsing initialization files, and configuring the readline environment.

def parse_and_bind(string): ...
def read_init_file(filename=None): ...

Configuration

History Management

Comprehensive history management including file operations, length control, and direct history manipulation with functions for reading, writing, and modifying command history.

def read_history_file(filename=None): ...
def write_history_file(filename=None): ...
def set_history_length(length): ...
def get_history_length(): ...
def add_history(string): ...

History Management

Line Editing

Functions for accessing and manipulating the current line buffer, enabling custom editing behavior and text insertion capabilities.

def get_line_buffer(): ...
def insert_text(string): ...
def redisplay(): ...

Line Editing

Tab Completion

Comprehensive tab completion system with customizable completion functions, delimiter configuration, and completion context access.

def set_completer(function=None): ...
def get_completer(): ...
def set_completer_delims(string): ...
def get_completer_delims(): ...

Tab Completion

Event Hooks

Advanced customization through event hooks that execute at specific points in the readline process, enabling custom display and input handling.

def set_startup_hook(function=None): ...
def set_pre_input_hook(function=None): ...
def set_completion_display_matches_hook(function=None): ...

Event Hooks