JezK
Edit File: Percolator.py
from idlelib.WidgetRedirector import WidgetRedirector from idlelib.Delegator import Delegator class Percolator: def __init__(self, text): # XXX would be nice to inherit from Delegator self.text = text self.redir = WidgetRedirector(text) self.top = self.bottom = Delegator(text) self.bottom.insert = self.redir.register("insert", self.insert) self.bottom.delete = self.redir.register("delete", self.delete) self.filters = [] def close(self): while self.top is not self.bottom: self.removefilter(self.top) self.top = None self.bottom.setdelegate(None); self.bottom = None self.redir.close(); self.redir = None self.text = None def insert(self, index, chars, tags=None): # Could go away if inheriting from Delegator self.top.insert(index, chars, tags) def delete(self, index1, index2=None): # Could go away if inheriting from Delegator self.top.delete(index1, index2) def insertfilter(self, filter): # Perhaps rename to pushfilter()? assert isinstance(filter, Delegator) assert filter.delegate is None filter.setdelegate(self.top) self.top = filter def removefilter(self, filter): # XXX Perhaps should only support popfilter()? assert isinstance(filter, Delegator) assert filter.delegate is not None f = self.top if f is filter: self.top = filter.delegate filter.setdelegate(None) else: while f.delegate is not filter: assert f is not self.bottom f.resetcache() f = f.delegate f.setdelegate(filter.delegate) filter.setdelegate(None) def main(): import tkinter as Tk class Tracer(Delegator): def __init__(self, name): self.name = name Delegator.__init__(self, None) def insert(self, *args): print(self.name, ": insert", args) self.delegate.insert(*args) def delete(self, *args): print(self.name, ": delete", args) self.delegate.delete(*args) root = Tk.Tk() root.wm_protocol("WM_DELETE_WINDOW", root.quit) text = Tk.Text() text.pack() text.focus_set() p = Percolator(text) t1 = Tracer("t1") t2 = Tracer("t2") p.insertfilter(t1) p.insertfilter(t2) root.mainloop() # click close widget to continue... p.removefilter(t2) root.mainloop() p.insertfilter(t2) p.removefilter(t1) root.mainloop() if __name__ == "__main__": main()