Someone, either Glyph or Tommi, mentioned that they wanted cursors a while back. "What's that," I asked; then thought "hm. I could do that." But I didn't. Only, now I did. I think. -- The moon is waxing gibbous, 58.9% illuminated, 8.2 days old. # -*- Python -*- # Kevin Turner <acapnotic@foobox.net>, November 23, 2001 # This code is in the Public Domain. from UserList import UserList import types class CursoredList(UserList): _cursorlist = None def __init__(self, seq=None): UserList.__init__(self, seq) def setCursor(self): if self._cursorlist is None: self._cursorlist = [] self._cursorlist[:] = range(len(self.data)) self._cursorLen = len(self.data) def cursor(self, key): if self._cursorlist is None: return self.__getitem__(key) if isinstance(key, types.SliceType): start, stop, step = key.start, key.stop, key.step if not step: step = 1 if start is None: start = 0 elif start < 0: start = self._cursorLen + start if (stop is None) or (stop > self._cursorLen): stop = self._cursorLen elif stop < 0: start = self._cursorLen + stop result = [] for i in xrange(start, stop, step): result.append(self.cursor(i)) return result else: key = int(key) if key < 0: key = self._cursorLen + key assert(0 <= key < self._cursorLen) new_key = self._cursorlist.index(key) return self.__getitem__(new_key) def __setitem__(self, key, value): if (self._cursorlist is not None) \ and isinstance(key, types.SliceType): self._cursorlist[key.start:key.stop] = [None] * len(value) if isinstance(key, types.SliceType): self.data[key.start:key.stop] = value else: self.data[key] = value def __getitem__(self, key): if isinstance(key, types.SliceType): return self.data[key.start:key.stop] else: return self.data[key] def __delitem__(self, key): if not isinstance(key, types.SliceType): key = slice(key, key+1) self.__setitem__(key, []) def __getslice__(self, start, stop): return self.__getitem__(slice(start, stop)) def __setslice__(self, start, stop, value): return self.__setitem__(slice(start, stop), value) def __delslice__(self, start, stop): return self.__delitem__(slice(start, stop)) def __iadd__(self, other): self.extend(other) return self def __imul__(self, multiplier): if self._cursorlist is not None: self._cursorlist.extend(([None] * len(self.data)) * (multiplier-1)) self.data[:] = self.data * multiplier def append(self, item): self[len(self):len(self)] = [item] def insert(self, i, item): self[i:i] = [item] def pop(self, i=-1): value = self[i] del self[i] return value def remove(self, item): i = self.index(item) del self[i] def reverse(self): self.data.reverse() if self._cursorlist is not None: self._cursorlist.reverse() def sort(self, cmpfunc=None): if self._cursorlist is not None: zipped = map(None, self.data, self._cursorlist) if cmpfunc: # The supplied cmpfunc won't be expecting the zipped list. cmpfunc_ = lambda x, y, c=cmpfunc: c(x[0], y[0]) zipped.sort(cmpfunc_) else: zipped.sort() for i in range(len(zipped)): self.data[i], self._cursorlist[i] = zipped[i] else: self.data.sort() def extend(self, other): self[len(self):len(self)] = other