Added two modules for ASCII characters and a simple editing form (ESR)

1 files changed, 159 insertions, 0 deletions

diff --git a/Lib/curses/textpad.py b/Lib/curses/textpad.py
new file mode 100644
index 00000000000..cd681748453
--- /dev/null
+++ b/Lib/curses/textpad.py
@@ -0,0 +1,159 @@
+"""curses.textpad
+
+"""
+
+import sys, curses, ascii
+
+def rectangle(win, uly, ulx, lry, lrx):
+    "Draw a rectangle."
+    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 (nospaces off) or end of line (nospaces on).
+    Ctrl-F      Cursor right, wrapping to next line when appropriate.
+    Ctrl-G      Terminate, returning the window contents.
+    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
+    """
+    def __init__(self, win):
+        self.win = win
+        (self.maxy, self.maxx) = win.getmaxyx()
+        self.maxy = self.maxy - 1
+        self.maxx = self.maxx - 1
+        self.stripspaces = 1
+        win.keypad(1)
+
+    def firstblank(self, y):
+        "Go to the location of the first blank on the given line."
+        (oldy, oldx) = self.win.getyx()
+        self.win.move(y, self.maxx-1)
+        last = self.maxx-1
+        while 1:
+            if last == 0:
+                break
+            if ascii.ascii(self.win.inch(y, last)) != ascii.SP:
+                last = last + 1
+                break
+            last = last - 1
+        self.win.move(oldy, oldx)
+        return last
+
+    def do_command(self, ch):
+        "Process a single editing command."
+        (y, x) = self.win.getyx()
+        if ascii.isprint(ch):
+            if y < self.maxy or x < self.maxx:
+                # The try-catch ignores the error we trigger from some curses
+                # versions by trying to write into the lowest-rightmost spot
+                # in the self.window.
+                try:
+                    self.win.addch(ch)
+                except ERR:
+                    pass
+        elif ch == ascii.SOH:				# Ctrl-a
+            self.win.move(y, 0)
+        elif ch in (ascii.STX, curses.KEY_LEFT):	# Ctrl-b
+            if x > 0:
+                self.win.move(y, x-1)
+            elif y == 0:
+                pass
+            elif self.stripspaces:
+                self.win.move(y-1, self.firstblank(y-1))
+            else:
+                self.win.move(y-1, self.maxx)
+        elif ch == ascii.EOT:				# Ctrl-d
+            self.win.delch()
+        elif ch == ascii.ENQ:				# Ctrl-e
+            if self.stripspaces:
+                self.win.move(y, self.firstblank(y, maxx))
+            else:
+                self.win.move(y, self.maxx)
+        elif ch in (ascii.ACK, curses.KEY_RIGHT):	# Ctrl-f
+            if x < self.maxx:
+                self.win.move(y, x+1)
+            elif y == self.maxx:
+                pass
+            else:
+                self.win.move(y+1, 0)
+        elif ch == ascii.BEL:				# Ctrl-g
+            return 0
+        elif ch == ascii.NL:				# Ctrl-j
+            if self.maxy == 0:
+                return 0
+            elif y < self.maxy:
+                self.win.move(y+1, 0)
+        elif ch == ascii.VT:				# Ctrl-k
+            if x == 0 and self.firstblank(y) == 0:
+                self.win.deleteln()
+            else:
+                self.win.clrtoeol()
+        elif ch == ascii.FF:				# Ctrl-l
+            self.win.refresh()
+        elif ch in (ascii.SO, curses.KEY_DOWN):		# Ctrl-n
+            if y < self.maxy:
+                self.win.move(y+1, x)
+        elif ch == ascii.SI:				# Ctrl-o
+            self.win.insertln()
+        elif ch in (ascii.DLE, curses.KEY_UP):		# Ctrl-p
+            if y > 0:
+                self.win.move(y-1, x)
+        self.win.refresh()
+        return 1
+        
+    def gather(self):
+        "Collect and return the contents of the window."
+        result = ""
+        for y in range(self.maxy+1):
+            self.win.move(y, 0)
+            stop = self.firstblank(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(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 self.do_command(ch):
+                break
+        return self.gather()
+
+if __name__ == '__main__':
+    def test_editbox(stdscr):
+        win = curses.newwin(4, 9, 15, 20)
+        rectangle(stdscr, 14, 19, 19, 29)
+        stdscr.refresh()
+        return textbox(win).edit()
+
+    str = curses.wrapper(test_editbox)
+    print str