1053 lines
36 KiB
Python
1053 lines
36 KiB
Python
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# Natural Language Toolkit: Recursive Descent Parser Application
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#
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# Copyright (C) 2001-2023 NLTK Project
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# Author: Edward Loper <edloper@gmail.com>
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# URL: <https://www.nltk.org/>
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# For license information, see LICENSE.TXT
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"""
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A graphical tool for exploring the recursive descent parser.
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The recursive descent parser maintains a tree, which records the
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structure of the portion of the text that has been parsed. It uses
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CFG productions to expand the fringe of the tree, and matches its
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leaves against the text. Initially, the tree contains the start
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symbol ("S"). It is shown in the main canvas, to the right of the
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list of available expansions.
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The parser builds up a tree structure for the text using three
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operations:
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- "expand" uses a CFG production to add children to a node on the
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fringe of the tree.
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- "match" compares a leaf in the tree to a text token.
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- "backtrack" returns the tree to its state before the most recent
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expand or match operation.
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The parser maintains a list of tree locations called a "frontier" to
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remember which nodes have not yet been expanded and which leaves have
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not yet been matched against the text. The leftmost frontier node is
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shown in green, and the other frontier nodes are shown in blue. The
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parser always performs expand and match operations on the leftmost
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element of the frontier.
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You can control the parser's operation by using the "expand," "match,"
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and "backtrack" buttons; or you can use the "step" button to let the
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parser automatically decide which operation to apply. The parser uses
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the following rules to decide which operation to apply:
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- If the leftmost frontier element is a token, try matching it.
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- If the leftmost frontier element is a node, try expanding it with
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the first untried expansion.
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- Otherwise, backtrack.
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The "expand" button applies the untried expansion whose CFG production
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is listed earliest in the grammar. To manually choose which expansion
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to apply, click on a CFG production from the list of available
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expansions, on the left side of the main window.
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The "autostep" button will let the parser continue applying
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applications to the tree until it reaches a complete parse. You can
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cancel an autostep in progress at any time by clicking on the
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"autostep" button again.
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Keyboard Shortcuts::
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[Space]\t Perform the next expand, match, or backtrack operation
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[a]\t Step through operations until the next complete parse
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[e]\t Perform an expand operation
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[m]\t Perform a match operation
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[b]\t Perform a backtrack operation
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[Delete]\t Reset the parser
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[g]\t Show/hide available expansions list
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[h]\t Help
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[Ctrl-p]\t Print
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[q]\t Quit
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"""
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from tkinter import Button, Frame, IntVar, Label, Listbox, Menu, Scrollbar, Tk
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from tkinter.font import Font
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from nltk.draw import CFGEditor, TreeSegmentWidget, tree_to_treesegment
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from nltk.draw.util import CanvasFrame, EntryDialog, ShowText, TextWidget
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from nltk.parse import SteppingRecursiveDescentParser
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from nltk.tree import Tree
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from nltk.util import in_idle
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class RecursiveDescentApp:
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"""
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A graphical tool for exploring the recursive descent parser. The tool
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displays the parser's tree and the remaining text, and allows the
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user to control the parser's operation. In particular, the user
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can expand subtrees on the frontier, match tokens on the frontier
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against the text, and backtrack. A "step" button simply steps
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through the parsing process, performing the operations that
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``RecursiveDescentParser`` would use.
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"""
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def __init__(self, grammar, sent, trace=0):
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self._sent = sent
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self._parser = SteppingRecursiveDescentParser(grammar, trace)
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# Set up the main window.
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self._top = Tk()
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self._top.title("Recursive Descent Parser Application")
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# Set up key bindings.
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self._init_bindings()
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# Initialize the fonts.
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self._init_fonts(self._top)
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# Animations. animating_lock is a lock to prevent the demo
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# from performing new operations while it's animating.
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self._animation_frames = IntVar(self._top)
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self._animation_frames.set(5)
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self._animating_lock = 0
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self._autostep = 0
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# The user can hide the grammar.
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self._show_grammar = IntVar(self._top)
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self._show_grammar.set(1)
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# Create the basic frames.
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self._init_menubar(self._top)
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self._init_buttons(self._top)
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self._init_feedback(self._top)
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self._init_grammar(self._top)
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self._init_canvas(self._top)
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# Initialize the parser.
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self._parser.initialize(self._sent)
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# Resize callback
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self._canvas.bind("<Configure>", self._configure)
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#########################################
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## Initialization Helpers
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#########################################
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def _init_fonts(self, root):
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# See: <http://www.astro.washington.edu/owen/ROTKFolklore.html>
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self._sysfont = Font(font=Button()["font"])
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root.option_add("*Font", self._sysfont)
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# TWhat's our font size (default=same as sysfont)
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self._size = IntVar(root)
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self._size.set(self._sysfont.cget("size"))
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self._boldfont = Font(family="helvetica", weight="bold", size=self._size.get())
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self._font = Font(family="helvetica", size=self._size.get())
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if self._size.get() < 0:
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big = self._size.get() - 2
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else:
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big = self._size.get() + 2
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self._bigfont = Font(family="helvetica", weight="bold", size=big)
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def _init_grammar(self, parent):
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# Grammar view.
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self._prodframe = listframe = Frame(parent)
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self._prodframe.pack(fill="both", side="left", padx=2)
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self._prodlist_label = Label(
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self._prodframe, font=self._boldfont, text="Available Expansions"
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)
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self._prodlist_label.pack()
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self._prodlist = Listbox(
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self._prodframe,
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selectmode="single",
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relief="groove",
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background="white",
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foreground="#909090",
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font=self._font,
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selectforeground="#004040",
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selectbackground="#c0f0c0",
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)
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self._prodlist.pack(side="right", fill="both", expand=1)
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self._productions = list(self._parser.grammar().productions())
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for production in self._productions:
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self._prodlist.insert("end", (" %s" % production))
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self._prodlist.config(height=min(len(self._productions), 25))
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# Add a scrollbar if there are more than 25 productions.
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if len(self._productions) > 25:
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listscroll = Scrollbar(self._prodframe, orient="vertical")
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self._prodlist.config(yscrollcommand=listscroll.set)
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listscroll.config(command=self._prodlist.yview)
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listscroll.pack(side="left", fill="y")
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# If they select a production, apply it.
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self._prodlist.bind("<<ListboxSelect>>", self._prodlist_select)
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def _init_bindings(self):
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# Key bindings are a good thing.
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self._top.bind("<Control-q>", self.destroy)
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self._top.bind("<Control-x>", self.destroy)
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self._top.bind("<Escape>", self.destroy)
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self._top.bind("e", self.expand)
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# self._top.bind('<Alt-e>', self.expand)
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# self._top.bind('<Control-e>', self.expand)
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self._top.bind("m", self.match)
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self._top.bind("<Alt-m>", self.match)
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self._top.bind("<Control-m>", self.match)
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self._top.bind("b", self.backtrack)
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self._top.bind("<Alt-b>", self.backtrack)
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self._top.bind("<Control-b>", self.backtrack)
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self._top.bind("<Control-z>", self.backtrack)
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self._top.bind("<BackSpace>", self.backtrack)
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self._top.bind("a", self.autostep)
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# self._top.bind('<Control-a>', self.autostep)
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self._top.bind("<Control-space>", self.autostep)
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self._top.bind("<Control-c>", self.cancel_autostep)
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self._top.bind("<space>", self.step)
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self._top.bind("<Delete>", self.reset)
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self._top.bind("<Control-p>", self.postscript)
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# self._top.bind('<h>', self.help)
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# self._top.bind('<Alt-h>', self.help)
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self._top.bind("<Control-h>", self.help)
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self._top.bind("<F1>", self.help)
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# self._top.bind('<g>', self.toggle_grammar)
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# self._top.bind('<Alt-g>', self.toggle_grammar)
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# self._top.bind('<Control-g>', self.toggle_grammar)
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self._top.bind("<Control-g>", self.edit_grammar)
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self._top.bind("<Control-t>", self.edit_sentence)
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def _init_buttons(self, parent):
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# Set up the frames.
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self._buttonframe = buttonframe = Frame(parent)
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buttonframe.pack(fill="none", side="bottom", padx=3, pady=2)
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Button(
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buttonframe,
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text="Step",
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background="#90c0d0",
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foreground="black",
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command=self.step,
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).pack(side="left")
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Button(
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buttonframe,
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text="Autostep",
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background="#90c0d0",
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foreground="black",
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command=self.autostep,
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).pack(side="left")
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Button(
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buttonframe,
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text="Expand",
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underline=0,
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background="#90f090",
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foreground="black",
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command=self.expand,
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).pack(side="left")
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Button(
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buttonframe,
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text="Match",
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underline=0,
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background="#90f090",
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foreground="black",
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command=self.match,
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).pack(side="left")
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Button(
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buttonframe,
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text="Backtrack",
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underline=0,
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background="#f0a0a0",
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foreground="black",
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command=self.backtrack,
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).pack(side="left")
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# Replace autostep...
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# self._autostep_button = Button(buttonframe, text='Autostep',
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# underline=0, command=self.autostep)
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# self._autostep_button.pack(side='left')
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def _configure(self, event):
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self._autostep = 0
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(x1, y1, x2, y2) = self._cframe.scrollregion()
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y2 = event.height - 6
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self._canvas["scrollregion"] = "%d %d %d %d" % (x1, y1, x2, y2)
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self._redraw()
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def _init_feedback(self, parent):
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self._feedbackframe = feedbackframe = Frame(parent)
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feedbackframe.pack(fill="x", side="bottom", padx=3, pady=3)
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self._lastoper_label = Label(
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feedbackframe, text="Last Operation:", font=self._font
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)
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self._lastoper_label.pack(side="left")
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lastoperframe = Frame(feedbackframe, relief="sunken", border=1)
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lastoperframe.pack(fill="x", side="right", expand=1, padx=5)
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self._lastoper1 = Label(
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lastoperframe, foreground="#007070", background="#f0f0f0", font=self._font
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)
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self._lastoper2 = Label(
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lastoperframe,
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anchor="w",
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width=30,
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foreground="#004040",
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background="#f0f0f0",
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font=self._font,
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)
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self._lastoper1.pack(side="left")
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self._lastoper2.pack(side="left", fill="x", expand=1)
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def _init_canvas(self, parent):
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self._cframe = CanvasFrame(
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parent,
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background="white",
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# width=525, height=250,
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closeenough=10,
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border=2,
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relief="sunken",
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)
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self._cframe.pack(expand=1, fill="both", side="top", pady=2)
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canvas = self._canvas = self._cframe.canvas()
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# Initially, there's no tree or text
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self._tree = None
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self._textwidgets = []
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self._textline = None
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def _init_menubar(self, parent):
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menubar = Menu(parent)
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filemenu = Menu(menubar, tearoff=0)
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filemenu.add_command(
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label="Reset Parser", underline=0, command=self.reset, accelerator="Del"
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)
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filemenu.add_command(
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label="Print to Postscript",
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underline=0,
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command=self.postscript,
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accelerator="Ctrl-p",
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)
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filemenu.add_command(
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label="Exit", underline=1, command=self.destroy, accelerator="Ctrl-x"
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)
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menubar.add_cascade(label="File", underline=0, menu=filemenu)
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editmenu = Menu(menubar, tearoff=0)
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editmenu.add_command(
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label="Edit Grammar",
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underline=5,
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command=self.edit_grammar,
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accelerator="Ctrl-g",
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)
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editmenu.add_command(
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label="Edit Text",
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underline=5,
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command=self.edit_sentence,
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accelerator="Ctrl-t",
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)
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menubar.add_cascade(label="Edit", underline=0, menu=editmenu)
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rulemenu = Menu(menubar, tearoff=0)
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rulemenu.add_command(
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label="Step", underline=1, command=self.step, accelerator="Space"
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)
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rulemenu.add_separator()
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rulemenu.add_command(
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label="Match", underline=0, command=self.match, accelerator="Ctrl-m"
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)
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rulemenu.add_command(
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label="Expand", underline=0, command=self.expand, accelerator="Ctrl-e"
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)
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rulemenu.add_separator()
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rulemenu.add_command(
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label="Backtrack", underline=0, command=self.backtrack, accelerator="Ctrl-b"
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)
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|
|
menubar.add_cascade(label="Apply", underline=0, menu=rulemenu)
|
||
|
|
|
||
|
|
viewmenu = Menu(menubar, tearoff=0)
|
||
|
|
viewmenu.add_checkbutton(
|
||
|
|
label="Show Grammar",
|
||
|
|
underline=0,
|
||
|
|
variable=self._show_grammar,
|
||
|
|
command=self._toggle_grammar,
|
||
|
|
)
|
||
|
|
viewmenu.add_separator()
|
||
|
|
viewmenu.add_radiobutton(
|
||
|
|
label="Tiny",
|
||
|
|
variable=self._size,
|
||
|
|
underline=0,
|
||
|
|
value=10,
|
||
|
|
command=self.resize,
|
||
|
|
)
|
||
|
|
viewmenu.add_radiobutton(
|
||
|
|
label="Small",
|
||
|
|
variable=self._size,
|
||
|
|
underline=0,
|
||
|
|
value=12,
|
||
|
|
command=self.resize,
|
||
|
|
)
|
||
|
|
viewmenu.add_radiobutton(
|
||
|
|
label="Medium",
|
||
|
|
variable=self._size,
|
||
|
|
underline=0,
|
||
|
|
value=14,
|
||
|
|
command=self.resize,
|
||
|
|
)
|
||
|
|
viewmenu.add_radiobutton(
|
||
|
|
label="Large",
|
||
|
|
variable=self._size,
|
||
|
|
underline=0,
|
||
|
|
value=18,
|
||
|
|
command=self.resize,
|
||
|
|
)
|
||
|
|
viewmenu.add_radiobutton(
|
||
|
|
label="Huge",
|
||
|
|
variable=self._size,
|
||
|
|
underline=0,
|
||
|
|
value=24,
|
||
|
|
command=self.resize,
|
||
|
|
)
|
||
|
|
menubar.add_cascade(label="View", underline=0, menu=viewmenu)
|
||
|
|
|
||
|
|
animatemenu = Menu(menubar, tearoff=0)
|
||
|
|
animatemenu.add_radiobutton(
|
||
|
|
label="No Animation", underline=0, variable=self._animation_frames, value=0
|
||
|
|
)
|
||
|
|
animatemenu.add_radiobutton(
|
||
|
|
label="Slow Animation",
|
||
|
|
underline=0,
|
||
|
|
variable=self._animation_frames,
|
||
|
|
value=10,
|
||
|
|
accelerator="-",
|
||
|
|
)
|
||
|
|
animatemenu.add_radiobutton(
|
||
|
|
label="Normal Animation",
|
||
|
|
underline=0,
|
||
|
|
variable=self._animation_frames,
|
||
|
|
value=5,
|
||
|
|
accelerator="=",
|
||
|
|
)
|
||
|
|
animatemenu.add_radiobutton(
|
||
|
|
label="Fast Animation",
|
||
|
|
underline=0,
|
||
|
|
variable=self._animation_frames,
|
||
|
|
value=2,
|
||
|
|
accelerator="+",
|
||
|
|
)
|
||
|
|
menubar.add_cascade(label="Animate", underline=1, menu=animatemenu)
|
||
|
|
|
||
|
|
helpmenu = Menu(menubar, tearoff=0)
|
||
|
|
helpmenu.add_command(label="About", underline=0, command=self.about)
|
||
|
|
helpmenu.add_command(
|
||
|
|
label="Instructions", underline=0, command=self.help, accelerator="F1"
|
||
|
|
)
|
||
|
|
menubar.add_cascade(label="Help", underline=0, menu=helpmenu)
|
||
|
|
|
||
|
|
parent.config(menu=menubar)
|
||
|
|
|
||
|
|
#########################################
|
||
|
|
## Helper
|
||
|
|
#########################################
|
||
|
|
|
||
|
|
def _get(self, widget, treeloc):
|
||
|
|
for i in treeloc:
|
||
|
|
widget = widget.subtrees()[i]
|
||
|
|
if isinstance(widget, TreeSegmentWidget):
|
||
|
|
widget = widget.label()
|
||
|
|
return widget
|
||
|
|
|
||
|
|
#########################################
|
||
|
|
## Main draw procedure
|
||
|
|
#########################################
|
||
|
|
|
||
|
|
def _redraw(self):
|
||
|
|
canvas = self._canvas
|
||
|
|
|
||
|
|
# Delete the old tree, widgets, etc.
|
||
|
|
if self._tree is not None:
|
||
|
|
self._cframe.destroy_widget(self._tree)
|
||
|
|
for twidget in self._textwidgets:
|
||
|
|
self._cframe.destroy_widget(twidget)
|
||
|
|
if self._textline is not None:
|
||
|
|
self._canvas.delete(self._textline)
|
||
|
|
|
||
|
|
# Draw the tree.
|
||
|
|
helv = ("helvetica", -self._size.get())
|
||
|
|
bold = ("helvetica", -self._size.get(), "bold")
|
||
|
|
attribs = {
|
||
|
|
"tree_color": "#000000",
|
||
|
|
"tree_width": 2,
|
||
|
|
"node_font": bold,
|
||
|
|
"leaf_font": helv,
|
||
|
|
}
|
||
|
|
tree = self._parser.tree()
|
||
|
|
self._tree = tree_to_treesegment(canvas, tree, **attribs)
|
||
|
|
self._cframe.add_widget(self._tree, 30, 5)
|
||
|
|
|
||
|
|
# Draw the text.
|
||
|
|
helv = ("helvetica", -self._size.get())
|
||
|
|
bottom = y = self._cframe.scrollregion()[3]
|
||
|
|
self._textwidgets = [
|
||
|
|
TextWidget(canvas, word, font=self._font) for word in self._sent
|
||
|
|
]
|
||
|
|
for twidget in self._textwidgets:
|
||
|
|
self._cframe.add_widget(twidget, 0, 0)
|
||
|
|
twidget.move(0, bottom - twidget.bbox()[3] - 5)
|
||
|
|
y = min(y, twidget.bbox()[1])
|
||
|
|
|
||
|
|
# Draw a line over the text, to separate it from the tree.
|
||
|
|
self._textline = canvas.create_line(-5000, y - 5, 5000, y - 5, dash=".")
|
||
|
|
|
||
|
|
# Highlight appropriate nodes.
|
||
|
|
self._highlight_nodes()
|
||
|
|
self._highlight_prodlist()
|
||
|
|
|
||
|
|
# Make sure the text lines up.
|
||
|
|
self._position_text()
|
||
|
|
|
||
|
|
def _redraw_quick(self):
|
||
|
|
# This should be more-or-less sufficient after an animation.
|
||
|
|
self._highlight_nodes()
|
||
|
|
self._highlight_prodlist()
|
||
|
|
self._position_text()
|
||
|
|
|
||
|
|
def _highlight_nodes(self):
|
||
|
|
# Highlight the list of nodes to be checked.
|
||
|
|
bold = ("helvetica", -self._size.get(), "bold")
|
||
|
|
for treeloc in self._parser.frontier()[:1]:
|
||
|
|
self._get(self._tree, treeloc)["color"] = "#20a050"
|
||
|
|
self._get(self._tree, treeloc)["font"] = bold
|
||
|
|
for treeloc in self._parser.frontier()[1:]:
|
||
|
|
self._get(self._tree, treeloc)["color"] = "#008080"
|
||
|
|
|
||
|
|
def _highlight_prodlist(self):
|
||
|
|
# Highlight the productions that can be expanded.
|
||
|
|
# Boy, too bad tkinter doesn't implement Listbox.itemconfig;
|
||
|
|
# that would be pretty useful here.
|
||
|
|
self._prodlist.delete(0, "end")
|
||
|
|
expandable = self._parser.expandable_productions()
|
||
|
|
untried = self._parser.untried_expandable_productions()
|
||
|
|
productions = self._productions
|
||
|
|
for index in range(len(productions)):
|
||
|
|
if productions[index] in expandable:
|
||
|
|
if productions[index] in untried:
|
||
|
|
self._prodlist.insert(index, " %s" % productions[index])
|
||
|
|
else:
|
||
|
|
self._prodlist.insert(index, " %s (TRIED)" % productions[index])
|
||
|
|
self._prodlist.selection_set(index)
|
||
|
|
else:
|
||
|
|
self._prodlist.insert(index, " %s" % productions[index])
|
||
|
|
|
||
|
|
def _position_text(self):
|
||
|
|
# Line up the text widgets that are matched against the tree
|
||
|
|
numwords = len(self._sent)
|
||
|
|
num_matched = numwords - len(self._parser.remaining_text())
|
||
|
|
leaves = self._tree_leaves()[:num_matched]
|
||
|
|
xmax = self._tree.bbox()[0]
|
||
|
|
for i in range(0, len(leaves)):
|
||
|
|
widget = self._textwidgets[i]
|
||
|
|
leaf = leaves[i]
|
||
|
|
widget["color"] = "#006040"
|
||
|
|
leaf["color"] = "#006040"
|
||
|
|
widget.move(leaf.bbox()[0] - widget.bbox()[0], 0)
|
||
|
|
xmax = widget.bbox()[2] + 10
|
||
|
|
|
||
|
|
# Line up the text widgets that are not matched against the tree.
|
||
|
|
for i in range(len(leaves), numwords):
|
||
|
|
widget = self._textwidgets[i]
|
||
|
|
widget["color"] = "#a0a0a0"
|
||
|
|
widget.move(xmax - widget.bbox()[0], 0)
|
||
|
|
xmax = widget.bbox()[2] + 10
|
||
|
|
|
||
|
|
# If we have a complete parse, make everything green :)
|
||
|
|
if self._parser.currently_complete():
|
||
|
|
for twidget in self._textwidgets:
|
||
|
|
twidget["color"] = "#00a000"
|
||
|
|
|
||
|
|
# Move the matched leaves down to the text.
|
||
|
|
for i in range(0, len(leaves)):
|
||
|
|
widget = self._textwidgets[i]
|
||
|
|
leaf = leaves[i]
|
||
|
|
dy = widget.bbox()[1] - leaf.bbox()[3] - 10.0
|
||
|
|
dy = max(dy, leaf.parent().label().bbox()[3] - leaf.bbox()[3] + 10)
|
||
|
|
leaf.move(0, dy)
|
||
|
|
|
||
|
|
def _tree_leaves(self, tree=None):
|
||
|
|
if tree is None:
|
||
|
|
tree = self._tree
|
||
|
|
if isinstance(tree, TreeSegmentWidget):
|
||
|
|
leaves = []
|
||
|
|
for child in tree.subtrees():
|
||
|
|
leaves += self._tree_leaves(child)
|
||
|
|
return leaves
|
||
|
|
else:
|
||
|
|
return [tree]
|
||
|
|
|
||
|
|
#########################################
|
||
|
|
## Button Callbacks
|
||
|
|
#########################################
|
||
|
|
|
||
|
|
def destroy(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
if self._top is None:
|
||
|
|
return
|
||
|
|
self._top.destroy()
|
||
|
|
self._top = None
|
||
|
|
|
||
|
|
def reset(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._parser.initialize(self._sent)
|
||
|
|
self._lastoper1["text"] = "Reset Application"
|
||
|
|
self._lastoper2["text"] = ""
|
||
|
|
self._redraw()
|
||
|
|
|
||
|
|
def autostep(self, *e):
|
||
|
|
if self._animation_frames.get() == 0:
|
||
|
|
self._animation_frames.set(2)
|
||
|
|
if self._autostep:
|
||
|
|
self._autostep = 0
|
||
|
|
else:
|
||
|
|
self._autostep = 1
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def cancel_autostep(self, *e):
|
||
|
|
# self._autostep_button['text'] = 'Autostep'
|
||
|
|
self._autostep = 0
|
||
|
|
|
||
|
|
# Make sure to stop auto-stepping if we get any user input.
|
||
|
|
def step(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def match(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._match()
|
||
|
|
|
||
|
|
def expand(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._expand()
|
||
|
|
|
||
|
|
def backtrack(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._backtrack()
|
||
|
|
|
||
|
|
def _step(self):
|
||
|
|
if self._animating_lock:
|
||
|
|
return
|
||
|
|
|
||
|
|
# Try expanding, matching, and backtracking (in that order)
|
||
|
|
if self._expand():
|
||
|
|
pass
|
||
|
|
elif self._parser.untried_match() and self._match():
|
||
|
|
pass
|
||
|
|
elif self._backtrack():
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
self._lastoper1["text"] = "Finished"
|
||
|
|
self._lastoper2["text"] = ""
|
||
|
|
self._autostep = 0
|
||
|
|
|
||
|
|
# Check if we just completed a parse.
|
||
|
|
if self._parser.currently_complete():
|
||
|
|
self._autostep = 0
|
||
|
|
self._lastoper2["text"] += " [COMPLETE PARSE]"
|
||
|
|
|
||
|
|
def _expand(self, *e):
|
||
|
|
if self._animating_lock:
|
||
|
|
return
|
||
|
|
old_frontier = self._parser.frontier()
|
||
|
|
rv = self._parser.expand()
|
||
|
|
if rv is not None:
|
||
|
|
self._lastoper1["text"] = "Expand:"
|
||
|
|
self._lastoper2["text"] = rv
|
||
|
|
self._prodlist.selection_clear(0, "end")
|
||
|
|
index = self._productions.index(rv)
|
||
|
|
self._prodlist.selection_set(index)
|
||
|
|
self._animate_expand(old_frontier[0])
|
||
|
|
return True
|
||
|
|
else:
|
||
|
|
self._lastoper1["text"] = "Expand:"
|
||
|
|
self._lastoper2["text"] = "(all expansions tried)"
|
||
|
|
return False
|
||
|
|
|
||
|
|
def _match(self, *e):
|
||
|
|
if self._animating_lock:
|
||
|
|
return
|
||
|
|
old_frontier = self._parser.frontier()
|
||
|
|
rv = self._parser.match()
|
||
|
|
if rv is not None:
|
||
|
|
self._lastoper1["text"] = "Match:"
|
||
|
|
self._lastoper2["text"] = rv
|
||
|
|
self._animate_match(old_frontier[0])
|
||
|
|
return True
|
||
|
|
else:
|
||
|
|
self._lastoper1["text"] = "Match:"
|
||
|
|
self._lastoper2["text"] = "(failed)"
|
||
|
|
return False
|
||
|
|
|
||
|
|
def _backtrack(self, *e):
|
||
|
|
if self._animating_lock:
|
||
|
|
return
|
||
|
|
if self._parser.backtrack():
|
||
|
|
elt = self._parser.tree()
|
||
|
|
for i in self._parser.frontier()[0]:
|
||
|
|
elt = elt[i]
|
||
|
|
self._lastoper1["text"] = "Backtrack"
|
||
|
|
self._lastoper2["text"] = ""
|
||
|
|
if isinstance(elt, Tree):
|
||
|
|
self._animate_backtrack(self._parser.frontier()[0])
|
||
|
|
else:
|
||
|
|
self._animate_match_backtrack(self._parser.frontier()[0])
|
||
|
|
return True
|
||
|
|
else:
|
||
|
|
self._autostep = 0
|
||
|
|
self._lastoper1["text"] = "Finished"
|
||
|
|
self._lastoper2["text"] = ""
|
||
|
|
return False
|
||
|
|
|
||
|
|
def about(self, *e):
|
||
|
|
ABOUT = (
|
||
|
|
"NLTK Recursive Descent Parser Application\n" + "Written by Edward Loper"
|
||
|
|
)
|
||
|
|
TITLE = "About: Recursive Descent Parser Application"
|
||
|
|
try:
|
||
|
|
from tkinter.messagebox import Message
|
||
|
|
|
||
|
|
Message(message=ABOUT, title=TITLE).show()
|
||
|
|
except:
|
||
|
|
ShowText(self._top, TITLE, ABOUT)
|
||
|
|
|
||
|
|
def help(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
# The default font's not very legible; try using 'fixed' instead.
|
||
|
|
try:
|
||
|
|
ShowText(
|
||
|
|
self._top,
|
||
|
|
"Help: Recursive Descent Parser Application",
|
||
|
|
(__doc__ or "").strip(),
|
||
|
|
width=75,
|
||
|
|
font="fixed",
|
||
|
|
)
|
||
|
|
except:
|
||
|
|
ShowText(
|
||
|
|
self._top,
|
||
|
|
"Help: Recursive Descent Parser Application",
|
||
|
|
(__doc__ or "").strip(),
|
||
|
|
width=75,
|
||
|
|
)
|
||
|
|
|
||
|
|
def postscript(self, *e):
|
||
|
|
self._autostep = 0
|
||
|
|
self._cframe.print_to_file()
|
||
|
|
|
||
|
|
def mainloop(self, *args, **kwargs):
|
||
|
|
"""
|
||
|
|
Enter the Tkinter mainloop. This function must be called if
|
||
|
|
this demo is created from a non-interactive program (e.g.
|
||
|
|
from a secript); otherwise, the demo will close as soon as
|
||
|
|
the script completes.
|
||
|
|
"""
|
||
|
|
if in_idle():
|
||
|
|
return
|
||
|
|
self._top.mainloop(*args, **kwargs)
|
||
|
|
|
||
|
|
def resize(self, size=None):
|
||
|
|
if size is not None:
|
||
|
|
self._size.set(size)
|
||
|
|
size = self._size.get()
|
||
|
|
self._font.configure(size=-(abs(size)))
|
||
|
|
self._boldfont.configure(size=-(abs(size)))
|
||
|
|
self._sysfont.configure(size=-(abs(size)))
|
||
|
|
self._bigfont.configure(size=-(abs(size + 2)))
|
||
|
|
self._redraw()
|
||
|
|
|
||
|
|
#########################################
|
||
|
|
## Expand Production Selection
|
||
|
|
#########################################
|
||
|
|
|
||
|
|
def _toggle_grammar(self, *e):
|
||
|
|
if self._show_grammar.get():
|
||
|
|
self._prodframe.pack(
|
||
|
|
fill="both", side="left", padx=2, after=self._feedbackframe
|
||
|
|
)
|
||
|
|
self._lastoper1["text"] = "Show Grammar"
|
||
|
|
else:
|
||
|
|
self._prodframe.pack_forget()
|
||
|
|
self._lastoper1["text"] = "Hide Grammar"
|
||
|
|
self._lastoper2["text"] = ""
|
||
|
|
|
||
|
|
# def toggle_grammar(self, *e):
|
||
|
|
# self._show_grammar = not self._show_grammar
|
||
|
|
# if self._show_grammar:
|
||
|
|
# self._prodframe.pack(fill='both', expand='y', side='left',
|
||
|
|
# after=self._feedbackframe)
|
||
|
|
# self._lastoper1['text'] = 'Show Grammar'
|
||
|
|
# else:
|
||
|
|
# self._prodframe.pack_forget()
|
||
|
|
# self._lastoper1['text'] = 'Hide Grammar'
|
||
|
|
# self._lastoper2['text'] = ''
|
||
|
|
|
||
|
|
def _prodlist_select(self, event):
|
||
|
|
selection = self._prodlist.curselection()
|
||
|
|
if len(selection) != 1:
|
||
|
|
return
|
||
|
|
index = int(selection[0])
|
||
|
|
old_frontier = self._parser.frontier()
|
||
|
|
production = self._parser.expand(self._productions[index])
|
||
|
|
|
||
|
|
if production:
|
||
|
|
self._lastoper1["text"] = "Expand:"
|
||
|
|
self._lastoper2["text"] = production
|
||
|
|
self._prodlist.selection_clear(0, "end")
|
||
|
|
self._prodlist.selection_set(index)
|
||
|
|
self._animate_expand(old_frontier[0])
|
||
|
|
else:
|
||
|
|
# Reset the production selections.
|
||
|
|
self._prodlist.selection_clear(0, "end")
|
||
|
|
for prod in self._parser.expandable_productions():
|
||
|
|
index = self._productions.index(prod)
|
||
|
|
self._prodlist.selection_set(index)
|
||
|
|
|
||
|
|
#########################################
|
||
|
|
## Animation
|
||
|
|
#########################################
|
||
|
|
|
||
|
|
def _animate_expand(self, treeloc):
|
||
|
|
oldwidget = self._get(self._tree, treeloc)
|
||
|
|
oldtree = oldwidget.parent()
|
||
|
|
top = not isinstance(oldtree.parent(), TreeSegmentWidget)
|
||
|
|
|
||
|
|
tree = self._parser.tree()
|
||
|
|
for i in treeloc:
|
||
|
|
tree = tree[i]
|
||
|
|
|
||
|
|
widget = tree_to_treesegment(
|
||
|
|
self._canvas,
|
||
|
|
tree,
|
||
|
|
node_font=self._boldfont,
|
||
|
|
leaf_color="white",
|
||
|
|
tree_width=2,
|
||
|
|
tree_color="white",
|
||
|
|
node_color="white",
|
||
|
|
leaf_font=self._font,
|
||
|
|
)
|
||
|
|
widget.label()["color"] = "#20a050"
|
||
|
|
|
||
|
|
(oldx, oldy) = oldtree.label().bbox()[:2]
|
||
|
|
(newx, newy) = widget.label().bbox()[:2]
|
||
|
|
widget.move(oldx - newx, oldy - newy)
|
||
|
|
|
||
|
|
if top:
|
||
|
|
self._cframe.add_widget(widget, 0, 5)
|
||
|
|
widget.move(30 - widget.label().bbox()[0], 0)
|
||
|
|
self._tree = widget
|
||
|
|
else:
|
||
|
|
oldtree.parent().replace_child(oldtree, widget)
|
||
|
|
|
||
|
|
# Move the children over so they don't overlap.
|
||
|
|
# Line the children up in a strange way.
|
||
|
|
if widget.subtrees():
|
||
|
|
dx = (
|
||
|
|
oldx
|
||
|
|
+ widget.label().width() / 2
|
||
|
|
- widget.subtrees()[0].bbox()[0] / 2
|
||
|
|
- widget.subtrees()[0].bbox()[2] / 2
|
||
|
|
)
|
||
|
|
for subtree in widget.subtrees():
|
||
|
|
subtree.move(dx, 0)
|
||
|
|
|
||
|
|
self._makeroom(widget)
|
||
|
|
|
||
|
|
if top:
|
||
|
|
self._cframe.destroy_widget(oldtree)
|
||
|
|
else:
|
||
|
|
oldtree.destroy()
|
||
|
|
|
||
|
|
colors = [
|
||
|
|
"gray%d" % (10 * int(10 * x / self._animation_frames.get()))
|
||
|
|
for x in range(self._animation_frames.get(), 0, -1)
|
||
|
|
]
|
||
|
|
|
||
|
|
# Move the text string down, if necessary.
|
||
|
|
dy = widget.bbox()[3] + 30 - self._canvas.coords(self._textline)[1]
|
||
|
|
if dy > 0:
|
||
|
|
for twidget in self._textwidgets:
|
||
|
|
twidget.move(0, dy)
|
||
|
|
self._canvas.move(self._textline, 0, dy)
|
||
|
|
|
||
|
|
self._animate_expand_frame(widget, colors)
|
||
|
|
|
||
|
|
def _makeroom(self, treeseg):
|
||
|
|
"""
|
||
|
|
Make sure that no sibling tree bbox's overlap.
|
||
|
|
"""
|
||
|
|
parent = treeseg.parent()
|
||
|
|
if not isinstance(parent, TreeSegmentWidget):
|
||
|
|
return
|
||
|
|
|
||
|
|
index = parent.subtrees().index(treeseg)
|
||
|
|
|
||
|
|
# Handle siblings to the right
|
||
|
|
rsiblings = parent.subtrees()[index + 1 :]
|
||
|
|
if rsiblings:
|
||
|
|
dx = treeseg.bbox()[2] - rsiblings[0].bbox()[0] + 10
|
||
|
|
for sibling in rsiblings:
|
||
|
|
sibling.move(dx, 0)
|
||
|
|
|
||
|
|
# Handle siblings to the left
|
||
|
|
if index > 0:
|
||
|
|
lsibling = parent.subtrees()[index - 1]
|
||
|
|
dx = max(0, lsibling.bbox()[2] - treeseg.bbox()[0] + 10)
|
||
|
|
treeseg.move(dx, 0)
|
||
|
|
|
||
|
|
# Keep working up the tree.
|
||
|
|
self._makeroom(parent)
|
||
|
|
|
||
|
|
def _animate_expand_frame(self, widget, colors):
|
||
|
|
if len(colors) > 0:
|
||
|
|
self._animating_lock = 1
|
||
|
|
widget["color"] = colors[0]
|
||
|
|
for subtree in widget.subtrees():
|
||
|
|
if isinstance(subtree, TreeSegmentWidget):
|
||
|
|
subtree.label()["color"] = colors[0]
|
||
|
|
else:
|
||
|
|
subtree["color"] = colors[0]
|
||
|
|
self._top.after(50, self._animate_expand_frame, widget, colors[1:])
|
||
|
|
else:
|
||
|
|
widget["color"] = "black"
|
||
|
|
for subtree in widget.subtrees():
|
||
|
|
if isinstance(subtree, TreeSegmentWidget):
|
||
|
|
subtree.label()["color"] = "black"
|
||
|
|
else:
|
||
|
|
subtree["color"] = "black"
|
||
|
|
self._redraw_quick()
|
||
|
|
widget.label()["color"] = "black"
|
||
|
|
self._animating_lock = 0
|
||
|
|
if self._autostep:
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def _animate_backtrack(self, treeloc):
|
||
|
|
# Flash red first, if we're animating.
|
||
|
|
if self._animation_frames.get() == 0:
|
||
|
|
colors = []
|
||
|
|
else:
|
||
|
|
colors = ["#a00000", "#000000", "#a00000"]
|
||
|
|
colors += [
|
||
|
|
"gray%d" % (10 * int(10 * x / (self._animation_frames.get())))
|
||
|
|
for x in range(1, self._animation_frames.get() + 1)
|
||
|
|
]
|
||
|
|
|
||
|
|
widgets = [self._get(self._tree, treeloc).parent()]
|
||
|
|
for subtree in widgets[0].subtrees():
|
||
|
|
if isinstance(subtree, TreeSegmentWidget):
|
||
|
|
widgets.append(subtree.label())
|
||
|
|
else:
|
||
|
|
widgets.append(subtree)
|
||
|
|
|
||
|
|
self._animate_backtrack_frame(widgets, colors)
|
||
|
|
|
||
|
|
def _animate_backtrack_frame(self, widgets, colors):
|
||
|
|
if len(colors) > 0:
|
||
|
|
self._animating_lock = 1
|
||
|
|
for widget in widgets:
|
||
|
|
widget["color"] = colors[0]
|
||
|
|
self._top.after(50, self._animate_backtrack_frame, widgets, colors[1:])
|
||
|
|
else:
|
||
|
|
for widget in widgets[0].subtrees():
|
||
|
|
widgets[0].remove_child(widget)
|
||
|
|
widget.destroy()
|
||
|
|
self._redraw_quick()
|
||
|
|
self._animating_lock = 0
|
||
|
|
if self._autostep:
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def _animate_match_backtrack(self, treeloc):
|
||
|
|
widget = self._get(self._tree, treeloc)
|
||
|
|
node = widget.parent().label()
|
||
|
|
dy = (node.bbox()[3] - widget.bbox()[1] + 14) / max(
|
||
|
|
1, self._animation_frames.get()
|
||
|
|
)
|
||
|
|
self._animate_match_backtrack_frame(self._animation_frames.get(), widget, dy)
|
||
|
|
|
||
|
|
def _animate_match(self, treeloc):
|
||
|
|
widget = self._get(self._tree, treeloc)
|
||
|
|
|
||
|
|
dy = (self._textwidgets[0].bbox()[1] - widget.bbox()[3] - 10.0) / max(
|
||
|
|
1, self._animation_frames.get()
|
||
|
|
)
|
||
|
|
self._animate_match_frame(self._animation_frames.get(), widget, dy)
|
||
|
|
|
||
|
|
def _animate_match_frame(self, frame, widget, dy):
|
||
|
|
if frame > 0:
|
||
|
|
self._animating_lock = 1
|
||
|
|
widget.move(0, dy)
|
||
|
|
self._top.after(10, self._animate_match_frame, frame - 1, widget, dy)
|
||
|
|
else:
|
||
|
|
widget["color"] = "#006040"
|
||
|
|
self._redraw_quick()
|
||
|
|
self._animating_lock = 0
|
||
|
|
if self._autostep:
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def _animate_match_backtrack_frame(self, frame, widget, dy):
|
||
|
|
if frame > 0:
|
||
|
|
self._animating_lock = 1
|
||
|
|
widget.move(0, dy)
|
||
|
|
self._top.after(
|
||
|
|
10, self._animate_match_backtrack_frame, frame - 1, widget, dy
|
||
|
|
)
|
||
|
|
else:
|
||
|
|
widget.parent().remove_child(widget)
|
||
|
|
widget.destroy()
|
||
|
|
self._animating_lock = 0
|
||
|
|
if self._autostep:
|
||
|
|
self._step()
|
||
|
|
|
||
|
|
def edit_grammar(self, *e):
|
||
|
|
CFGEditor(self._top, self._parser.grammar(), self.set_grammar)
|
||
|
|
|
||
|
|
def set_grammar(self, grammar):
|
||
|
|
self._parser.set_grammar(grammar)
|
||
|
|
self._productions = list(grammar.productions())
|
||
|
|
self._prodlist.delete(0, "end")
|
||
|
|
for production in self._productions:
|
||
|
|
self._prodlist.insert("end", (" %s" % production))
|
||
|
|
|
||
|
|
def edit_sentence(self, *e):
|
||
|
|
sentence = " ".join(self._sent)
|
||
|
|
title = "Edit Text"
|
||
|
|
instr = "Enter a new sentence to parse."
|
||
|
|
EntryDialog(self._top, sentence, instr, self.set_sentence, title)
|
||
|
|
|
||
|
|
def set_sentence(self, sentence):
|
||
|
|
self._sent = sentence.split() # [XX] use tagged?
|
||
|
|
self.reset()
|
||
|
|
|
||
|
|
|
||
|
|
def app():
|
||
|
|
"""
|
||
|
|
Create a recursive descent parser demo, using a simple grammar and
|
||
|
|
text.
|
||
|
|
"""
|
||
|
|
from nltk.grammar import CFG
|
||
|
|
|
||
|
|
grammar = CFG.fromstring(
|
||
|
|
"""
|
||
|
|
# Grammatical productions.
|
||
|
|
S -> NP VP
|
||
|
|
NP -> Det N PP | Det N
|
||
|
|
VP -> V NP PP | V NP | V
|
||
|
|
PP -> P NP
|
||
|
|
# Lexical productions.
|
||
|
|
NP -> 'I'
|
||
|
|
Det -> 'the' | 'a'
|
||
|
|
N -> 'man' | 'park' | 'dog' | 'telescope'
|
||
|
|
V -> 'ate' | 'saw'
|
||
|
|
P -> 'in' | 'under' | 'with'
|
||
|
|
"""
|
||
|
|
)
|
||
|
|
|
||
|
|
sent = "the dog saw a man in the park".split()
|
||
|
|
|
||
|
|
RecursiveDescentApp(grammar, sent).mainloop()
|
||
|
|
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
app()
|
||
|
|
|
||
|
|
__all__ = ["app"]
|