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