# Input Handling

URL: /docs/usage/input/
Section: usage
Tags: input, keyboard, keys, terminal

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Milo's input system reads raw terminal input and translates escape sequences into structured Key objects. It handles arrows, function keys, modifiers, and platform differences. KeyReader KeyReader is a context manager that puts the terminal in raw mode and yields Key objects: from milo.input import KeyReader with KeyReader() as keys: for key in keys: print(f"Got: {key.name or key.char}") if key.ctrl and key.char == "c": break Key objects Each keypress produces a frozen Key dataclass: Key( char="a", # The character (or empty for special keys) name=None, # SpecialKey enum value for non-character keys ctrl=False, # Ctrl modifier alt=False, # Alt/Option modifier shift=False, # Shift modifier ) Special keys The SpecialKey enum covers all standard terminal keys: Category Keys Arrows UP, DOWN, LEFT, RIGHT Navigation HOME, END, PAGE_UP, PAGE_DOWN Editing INSERT, DELETE, BACKSPACE Control TAB, ENTER, ESCAPE Function F1 through F12 Escape sequences Milo includes a frozen lookup table mapping ANSI VT100/xterm escape sequences to Key objects. This covers: Plain keys (arrows, F-keys, Home, End, etc.) Shift+key variants Alt+key variants Ctrl+key variants Info How escape sequence parsing works When a raw byte stream arrives: If the first byte is \x1b (ESC), read ahead for a complete sequence Look up the sequence in the frozen table (_sequences.py) If found, produce the matching Key with the correct modifiers If not found, produce a Key with name=ESCAPE The frozen lookup table is built at import time — no runtime overhead per keypress. Platform support Unix / macOS Windows Uses termios + tty for raw mode, select for non-blocking reads. from milo.input._platform import raw_mode, read_char, is_tty if is_tty(): with raw_mode(): ch = read_char() Uses msvcrt for raw character reads. # Automatically selected on Windows — same KeyReader API with KeyReader() as keys: for key in keys: ... Tip Tip Use is_tty() to check if stdin is an interactive terminal before entering raw mode. This lets your app degrade gracefully when input is piped.

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Metadata:
- Author: lbliii
- Word Count: 316
- Reading Time: 2 minutes