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      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()
    102