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idlelib
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undo.py
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import string from idlelib.delegator import Delegator # tkinter import not needed because module does not create widgets, # although many methods operate on text widget arguments. #$ event <<redo>> #$ win <Control-y> #$ unix <Alt-z> #$ event <<undo>> #$ win <Control-z> #$ unix <Control-z> #$ event <<dump-undo-state>> #$ win <Control-backslash> #$ unix <Control-backslash> class UndoDelegator(Delegator): max_undo = 1000 def __init__(self): Delegator.__init__(self) self.reset_undo() def setdelegate(self, delegate): if self.delegate is not None: self.unbind("<<undo>>") self.unbind("<<redo>>") self.unbind("<<dump-undo-state>>") Delegator.setdelegate(self, delegate) if delegate is not None: self.bind("<<undo>>", self.undo_event) self.bind("<<redo>>", self.redo_event) self.bind("<<dump-undo-state>>", self.dump_event) def dump_event(self, event): from pprint import pprint pprint(self.undolist[:self.pointer]) print("pointer:", self.pointer, end=' ') print("saved:", self.saved, end=' ') print("can_merge:", self.can_merge, end=' ') print("get_saved():", self.get_saved()) pprint(self.undolist[self.pointer:]) return "break" def reset_undo(self): self.was_saved = -1 self.pointer = 0 self.undolist = [] self.undoblock = 0 # or a CommandSequence instance self.set_saved(1) def set_saved(self, flag): if flag: self.saved = self.pointer else: self.saved = -1 self.can_merge = False self.check_saved() def get_saved(self): return self.saved == self.pointer saved_change_hook = None def set_saved_change_hook(self, hook): self.saved_change_hook = hook was_saved = -1 def check_saved(self): is_saved = self.get_saved() if is_saved != self.was_saved: self.was_saved = is_saved if self.saved_change_hook: self.saved_change_hook() def insert(self, index, chars, tags=None): self.addcmd(InsertCommand(index, chars, tags)) def delete(self, index1, index2=None): self.addcmd(DeleteCommand(index1, index2)) # Clients should call undo_block_start() and undo_block_stop() # around a sequence of editing cmds to be treated as a unit by # undo & redo. Nested matching calls are OK, and the inner calls # then act like nops. OK too if no editing cmds, or only one # editing cmd, is issued in between: if no cmds, the whole # sequence has no effect; and if only one cmd, that cmd is entered # directly into the undo list, as if undo_block_xxx hadn't been # called. The intent of all that is to make this scheme easy # to use: all the client has to worry about is making sure each # _start() call is matched by a _stop() call. def undo_block_start(self): if self.undoblock == 0: self.undoblock = CommandSequence() self.undoblock.bump_depth() def undo_block_stop(self): if self.undoblock.bump_depth(-1) == 0: cmd = self.undoblock self.undoblock = 0 if len(cmd) > 0: if len(cmd) == 1: # no need to wrap a single cmd cmd = cmd.getcmd(0) # this blk of cmds, or single cmd, has already # been done, so don't execute it again self.addcmd(cmd, 0) def addcmd(self, cmd, execute=True): if execute: cmd.do(self.delegate) if self.undoblock != 0: self.undoblock.append(cmd) return if self.can_merge and self.pointer > 0: lastcmd = self.undolist[self.pointer-1] if lastcmd.merge(cmd): return self.undolist[self.pointer:] = [cmd] if self.saved > self.pointer: self.saved = -1 self.pointer = self.pointer + 1 if len(self.undolist) > self.max_undo: ##print "truncating undo list" del self.undolist[0] self.pointer = self.pointer - 1 if self.saved >= 0: self.saved = self.saved - 1 self.can_merge = True self.check_saved() def undo_event(self, event): if self.pointer == 0: self.bell() return "break" cmd = self.undolist[self.pointer - 1] cmd.undo(self.delegate) self.pointer = self.pointer - 1 self.can_merge = False self.check_saved() return "break" def redo_event(self, event): if self.pointer >= len(self.undolist): self.bell() return "break" cmd = self.undolist[self.pointer] cmd.redo(self.delegate) self.pointer = self.pointer + 1 self.can_merge = False self.check_saved() return "break" class Command: # Base class for Undoable commands tags = None def __init__(self, index1, index2, chars, tags=None): self.marks_before = {} self.marks_after = {} self.index1 = index1 self.index2 = index2 self.chars = chars if tags: self.tags = tags def __repr__(self): s = self.__class__.__name__ t = (self.index1, self.index2, self.chars, self.tags) if self.tags is None: t = t[:-1] return s + repr(t) def do(self, text): pass def redo(self, text): pass def undo(self, text): pass def merge(self, cmd): return 0 def save_marks(self, text): marks = {} for name in text.mark_names(): if name != "insert" and name != "current": marks[name] = text.index(name) return marks def set_marks(self, text, marks): for name, index in marks.items(): text.mark_set(name, index) class InsertCommand(Command): # Undoable insert command def __init__(self, index1, chars, tags=None): Command.__init__(self, index1, None, chars, tags) def do(self, text): self.marks_before = self.save_marks(text) self.index1 = text.index(self.index1) if text.compare(self.index1, ">", "end-1c"): # Insert before the final newline self.index1 = text.index("end-1c") text.insert(self.index1, self.chars, self.tags) self.index2 = text.index("%s+%dc" % (self.index1, len(self.chars))) self.marks_after = self.save_marks(text) ##sys.__stderr__.write("do: %s\n" % self) def redo(self, text): text.mark_set('insert', self.index1) text.insert(self.index1, self.chars, self.tags) self.set_marks(text, self.marks_after) text.see('insert') ##sys.__stderr__.write("redo: %s\n" % self) def undo(self, text): text.mark_set('insert', self.index1) text.delete(self.index1, self.index2) self.set_marks(text, self.marks_before) text.see('insert') ##sys.__stderr__.write("undo: %s\n" % self) def merge(self, cmd): if self.__class__ is not cmd.__class__: return False if self.index2 != cmd.index1: return False if self.tags != cmd.tags: return False if len(cmd.chars) != 1: return False if self.chars and \ self.classify(self.chars[-1]) != self.classify(cmd.chars): return False self.index2 = cmd.index2 self.chars = self.chars + cmd.chars return True alphanumeric = string.ascii_letters + string.digits + "_" def classify(self, c): if c in self.alphanumeric: return "alphanumeric" if c == "\n": return "newline" return "punctuation" class DeleteCommand(Command): # Undoable delete command def __init__(self, index1, index2=None): Command.__init__(self, index1, index2, None, None) def do(self, text): self.marks_before = self.save_marks(text) self.index1 = text.index(self.index1) if self.index2: self.index2 = text.index(self.index2) else: self.index2 = text.index(self.index1 + " +1c") if text.compare(self.index2, ">", "end-1c"): # Don't delete the final newline self.index2 = text.index("end-1c") self.chars = text.get(self.index1, self.index2) text.delete(self.index1, self.index2) self.marks_after = self.save_marks(text) ##sys.__stderr__.write("do: %s\n" % self) def redo(self, text): text.mark_set('insert', self.index1) text.delete(self.index1, self.index2) self.set_marks(text, self.marks_after) text.see('insert') ##sys.__stderr__.write("redo: %s\n" % self) def undo(self, text): text.mark_set('insert', self.index1) text.insert(self.index1, self.chars) self.set_marks(text, self.marks_before) text.see('insert') ##sys.__stderr__.write("undo: %s\n" % self) class CommandSequence(Command): # Wrapper for a sequence of undoable cmds to be undone/redone # as a unit def __init__(self): self.cmds = [] self.depth = 0 def __repr__(self): s = self.__class__.__name__ strs = [] for cmd in self.cmds: strs.append(f" {cmd!r}") return s + "(\n" + ",\n".join(strs) + "\n)" def __len__(self): return len(self.cmds) def append(self, cmd): self.cmds.append(cmd) def getcmd(self, i): return self.cmds[i] def redo(self, text): for cmd in self.cmds: cmd.redo(text) def undo(self, text): cmds = self.cmds[:] cmds.reverse() for cmd in cmds: cmd.undo(text) def bump_depth(self, incr=1): self.depth = self.depth + incr return self.depth def _undo_delegator(parent): # htest # from tkinter import Toplevel, Text, Button from idlelib.percolator import Percolator top = Toplevel(parent) top.title("Test UndoDelegator") x, y = map(int, parent.geometry().split('+')[1:]) top.geometry("+%d+%d" % (x, y + 175)) text = Text(top, height=10) text.pack() text.focus_set() p = Percolator(text) d = UndoDelegator() p.insertfilter(d) undo = Button(top, text="Undo", command=lambda:d.undo_event(None)) undo.pack(side='left') redo = Button(top, text="Redo", command=lambda:d.redo_event(None)) redo.pack(side='left') dump = Button(top, text="Dump", command=lambda:d.dump_event(None)) dump.pack(side='left') if __name__ == "__main__": from unittest import main main('idlelib.idle_test.test_undo', verbosity=2, exit=False) from idlelib.idle_test.htest import run run(_undo_delegator)