/usr/lib/python3.5/curses/textpad.py is in libpython3.5-stdlib 3.5.3-1+deb9u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | """Simple textbox editing widget with Emacs-like keybindings."""
import curses
import curses.ascii
def rectangle(win, uly, ulx, lry, lrx):
"""Draw a rectangle with corners at the provided upper-left
and lower-right coordinates.
"""
win.vline(uly+1, ulx, curses.ACS_VLINE, lry - uly - 1)
win.hline(uly, ulx+1, curses.ACS_HLINE, lrx - ulx - 1)
win.hline(lry, ulx+1, curses.ACS_HLINE, lrx - ulx - 1)
win.vline(uly+1, lrx, curses.ACS_VLINE, lry - uly - 1)
win.addch(uly, ulx, curses.ACS_ULCORNER)
win.addch(uly, lrx, curses.ACS_URCORNER)
win.addch(lry, lrx, curses.ACS_LRCORNER)
win.addch(lry, ulx, curses.ACS_LLCORNER)
class Textbox:
"""Editing widget using the interior of a window object.
Supports the following Emacs-like key bindings:
Ctrl-A Go to left edge of window.
Ctrl-B Cursor left, wrapping to previous line if appropriate.
Ctrl-D Delete character under cursor.
Ctrl-E Go to right edge (stripspaces off) or end of line (stripspaces on).
Ctrl-F Cursor right, wrapping to next line when appropriate.
Ctrl-G Terminate, returning the window contents.
Ctrl-H Delete character backward.
Ctrl-J Terminate if the window is 1 line, otherwise insert newline.
Ctrl-K If line is blank, delete it, otherwise clear to end of line.
Ctrl-L Refresh screen.
Ctrl-N Cursor down; move down one line.
Ctrl-O Insert a blank line at cursor location.
Ctrl-P Cursor up; move up one line.
Move operations do nothing if the cursor is at an edge where the movement
is not possible. The following synonyms are supported where possible:
KEY_LEFT = Ctrl-B, KEY_RIGHT = Ctrl-F, KEY_UP = Ctrl-P, KEY_DOWN = Ctrl-N
KEY_BACKSPACE = Ctrl-h
"""
def __init__(self, win, insert_mode=False):
self.win = win
self.insert_mode = insert_mode
self._update_max_yx()
self.stripspaces = 1
self.lastcmd = None
win.keypad(1)
def _update_max_yx(self):
maxy, maxx = self.win.getmaxyx()
self.maxy = maxy - 1
self.maxx = maxx - 1
def _end_of_line(self, y):
"""Go to the location of the first blank on the given line,
returning the index of the last non-blank character."""
self._update_max_yx()
last = self.maxx
while True:
if curses.ascii.ascii(self.win.inch(y, last)) != curses.ascii.SP:
last = min(self.maxx, last+1)
break
elif last == 0:
break
last = last - 1
return last
def _insert_printable_char(self, ch):
self._update_max_yx()
(y, x) = self.win.getyx()
backyx = None
while y < self.maxy or x < self.maxx:
if self.insert_mode:
oldch = self.win.inch()
# The try-catch ignores the error we trigger from some curses
# versions by trying to write into the lowest-rightmost spot
# in the window.
try:
self.win.addch(ch)
except curses.error:
pass
if not self.insert_mode or not curses.ascii.isprint(oldch):
break
ch = oldch
(y, x) = self.win.getyx()
# Remember where to put the cursor back since we are in insert_mode
if backyx is None:
backyx = y, x
if backyx is not None:
self.win.move(*backyx)
def do_command(self, ch):
"Process a single editing command."
self._update_max_yx()
(y, x) = self.win.getyx()
self.lastcmd = ch
if curses.ascii.isprint(ch):
if y < self.maxy or x < self.maxx:
self._insert_printable_char(ch)
elif ch == curses.ascii.SOH: # ^a
self.win.move(y, 0)
elif ch in (curses.ascii.STX,curses.KEY_LEFT, curses.ascii.BS,curses.KEY_BACKSPACE):
if x > 0:
self.win.move(y, x-1)
elif y == 0:
pass
elif self.stripspaces:
self.win.move(y-1, self._end_of_line(y-1))
else:
self.win.move(y-1, self.maxx)
if ch in (curses.ascii.BS, curses.KEY_BACKSPACE):
self.win.delch()
elif ch == curses.ascii.EOT: # ^d
self.win.delch()
elif ch == curses.ascii.ENQ: # ^e
if self.stripspaces:
self.win.move(y, self._end_of_line(y))
else:
self.win.move(y, self.maxx)
elif ch in (curses.ascii.ACK, curses.KEY_RIGHT): # ^f
if x < self.maxx:
self.win.move(y, x+1)
elif y == self.maxy:
pass
else:
self.win.move(y+1, 0)
elif ch == curses.ascii.BEL: # ^g
return 0
elif ch == curses.ascii.NL: # ^j
if self.maxy == 0:
return 0
elif y < self.maxy:
self.win.move(y+1, 0)
elif ch == curses.ascii.VT: # ^k
if x == 0 and self._end_of_line(y) == 0:
self.win.deleteln()
else:
# first undo the effect of self._end_of_line
self.win.move(y, x)
self.win.clrtoeol()
elif ch == curses.ascii.FF: # ^l
self.win.refresh()
elif ch in (curses.ascii.SO, curses.KEY_DOWN): # ^n
if y < self.maxy:
self.win.move(y+1, x)
if x > self._end_of_line(y+1):
self.win.move(y+1, self._end_of_line(y+1))
elif ch == curses.ascii.SI: # ^o
self.win.insertln()
elif ch in (curses.ascii.DLE, curses.KEY_UP): # ^p
if y > 0:
self.win.move(y-1, x)
if x > self._end_of_line(y-1):
self.win.move(y-1, self._end_of_line(y-1))
return 1
def gather(self):
"Collect and return the contents of the window."
result = ""
self._update_max_yx()
for y in range(self.maxy+1):
self.win.move(y, 0)
stop = self._end_of_line(y)
if stop == 0 and self.stripspaces:
continue
for x in range(self.maxx+1):
if self.stripspaces and x > stop:
break
result = result + chr(curses.ascii.ascii(self.win.inch(y, x)))
if self.maxy > 0:
result = result + "\n"
return result
def edit(self, validate=None):
"Edit in the widget window and collect the results."
while 1:
ch = self.win.getch()
if validate:
ch = validate(ch)
if not ch:
continue
if not self.do_command(ch):
break
self.win.refresh()
return self.gather()
if __name__ == '__main__':
def test_editbox(stdscr):
ncols, nlines = 9, 4
uly, ulx = 15, 20
stdscr.addstr(uly-2, ulx, "Use Ctrl-G to end editing.")
win = curses.newwin(nlines, ncols, uly, ulx)
rectangle(stdscr, uly-1, ulx-1, uly + nlines, ulx + ncols)
stdscr.refresh()
return Textbox(win).edit()
str = curses.wrapper(test_editbox)
print('Contents of text box:', repr(str))
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