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cpython/Lib/curses/__init__.py
Victor Stinner 6ae254aaa0
gh-120417: Add #noqa to used imports in the stdlib (#120421)
Tools such as ruff can ignore "imported but unused" warnings if a
line ends with "# noqa: F401". It avoids the temptation to remove
an import which is used effectively.
2024-06-13 16:14:50 +02:00

102 lines
3.3 KiB
Python

"""curses
The main package for curses support for Python. Normally used by importing
the package, and perhaps a particular module inside it.
import curses
from curses import textpad
curses.initscr()
...
"""
from _curses import *
import os as _os
import sys as _sys
# Some constants, most notably the ACS_* ones, are only added to the C
# _curses module's dictionary after initscr() is called. (Some
# versions of SGI's curses don't define values for those constants
# until initscr() has been called.) This wrapper function calls the
# underlying C initscr(), and then copies the constants from the
# _curses module to the curses package's dictionary. Don't do 'from
# curses import *' if you'll be needing the ACS_* constants.
def initscr():
import _curses, curses
# we call setupterm() here because it raises an error
# instead of calling exit() in error cases.
setupterm(term=_os.environ.get("TERM", "unknown"),
fd=_sys.__stdout__.fileno())
stdscr = _curses.initscr()
for key, value in _curses.__dict__.items():
if key[0:4] == 'ACS_' or key in ('LINES', 'COLS'):
setattr(curses, key, value)
return stdscr
# This is a similar wrapper for start_color(), which adds the COLORS and
# COLOR_PAIRS variables which are only available after start_color() is
# called.
def start_color():
import _curses, curses
retval = _curses.start_color()
if hasattr(_curses, 'COLORS'):
curses.COLORS = _curses.COLORS
if hasattr(_curses, 'COLOR_PAIRS'):
curses.COLOR_PAIRS = _curses.COLOR_PAIRS
return retval
# Import Python has_key() implementation if _curses doesn't contain has_key()
try:
has_key
except NameError:
from .has_key import has_key # noqa: F401
# Wrapper for the entire curses-based application. Runs a function which
# should be the rest of your curses-based application. If the application
# raises an exception, wrapper() will restore the terminal to a sane state so
# you can read the resulting traceback.
def wrapper(func, /, *args, **kwds):
"""Wrapper function that initializes curses and calls another function,
restoring normal keyboard/screen behavior on error.
The callable object 'func' is then passed the main window 'stdscr'
as its first argument, followed by any other arguments passed to
wrapper().
"""
try:
# Initialize curses
stdscr = initscr()
# Turn off echoing of keys, and enter cbreak mode,
# where no buffering is performed on keyboard input
noecho()
cbreak()
# In keypad mode, escape sequences for special keys
# (like the cursor keys) will be interpreted and
# a special value like curses.KEY_LEFT will be returned
stdscr.keypad(1)
# Start color, too. Harmless if the terminal doesn't have
# color; user can test with has_color() later on. The try/catch
# works around a minor bit of over-conscientiousness in the curses
# module -- the error return from C start_color() is ignorable.
try:
start_color()
except:
pass
return func(stdscr, *args, **kwds)
finally:
# Set everything back to normal
if 'stdscr' in locals():
stdscr.keypad(0)
echo()
nocbreak()
endwin()