1  """curses
       2  
       3  The main package for curses support for Python.  Normally used by importing
       4  the package, and perhaps a particular module inside it.
       5  
       6     import curses
       7     from curses import textpad
       8     curses.initscr()
       9     ...
      10  
      11  """
      12  
      13  from _curses import *
      14  import os as _os
      15  import sys as _sys
      16  
      17  # Some constants, most notably the ACS_* ones, are only added to the C
      18  # _curses module's dictionary after initscr() is called.  (Some
      19  # versions of SGI's curses don't define values for those constants
      20  # until initscr() has been called.)  This wrapper function calls the
      21  # underlying C initscr(), and then copies the constants from the
      22  # _curses module to the curses package's dictionary.  Don't do 'from
      23  # curses import *' if you'll be needing the ACS_* constants.
      24  
      25  def initscr():
      26      import _curses, curses
      27      # we call setupterm() here because it raises an error
      28      # instead of calling exit() in error cases.
      29      setupterm(term=_os.environ.get("TERM", "unknown"),
      30                fd=_sys.__stdout__.fileno())
      31      stdscr = _curses.initscr()
      32      for key, value in _curses.__dict__.items():
      33          if key[0:4] == 'ACS_' or key in ('LINES', 'COLS'):
      34              setattr(curses, key, value)
      35  
      36      return stdscr
      37  
      38  # This is a similar wrapper for start_color(), which adds the COLORS and
      39  # COLOR_PAIRS variables which are only available after start_color() is
      40  # called.
      41  
      42  def start_color():
      43      import _curses, curses
      44      retval = _curses.start_color()
      45      if hasattr(_curses, 'COLORS'):
      46          curses.COLORS = _curses.COLORS
      47      if hasattr(_curses, 'COLOR_PAIRS'):
      48          curses.COLOR_PAIRS = _curses.COLOR_PAIRS
      49      return retval
      50  
      51  # Import Python has_key() implementation if _curses doesn't contain has_key()
      52  
      53  try:
      54      has_key
      55  except NameError:
      56      from .has_key import has_key
      57  
      58  # Wrapper for the entire curses-based application.  Runs a function which
      59  # should be the rest of your curses-based application.  If the application
      60  # raises an exception, wrapper() will restore the terminal to a sane state so
      61  # you can read the resulting traceback.
      62  
      63  def wrapper(func, /, *args, **kwds):
      64      """Wrapper function that initializes curses and calls another function,
      65      restoring normal keyboard/screen behavior on error.
      66      The callable object 'func' is then passed the main window 'stdscr'
      67      as its first argument, followed by any other arguments passed to
      68      wrapper().
      69      """
      70  
      71      try:
      72          # Initialize curses
      73          stdscr = initscr()
      74  
      75          # Turn off echoing of keys, and enter cbreak mode,
      76          # where no buffering is performed on keyboard input
      77          noecho()
      78          cbreak()
      79  
      80          # In keypad mode, escape sequences for special keys
      81          # (like the cursor keys) will be interpreted and
      82          # a special value like curses.KEY_LEFT will be returned
      83          stdscr.keypad(1)
      84  
      85          # Start color, too.  Harmless if the terminal doesn't have
      86          # color; user can test with has_color() later on.  The try/catch
      87          # works around a minor bit of over-conscientiousness in the curses
      88          # module -- the error return from C start_color() is ignorable.
      89          try:
      90              start_color()
      91          except:
      92              pass
      93  
      94          return func(stdscr, *args, **kwds)
      95      finally:
      96          # Set everything back to normal
      97          if 'stdscr' in locals():
      98              stdscr.keypad(0)
      99              echo()
     100              nocbreak()
     101              endwin()