Coverage for nltk.app.rdparser_app : 12%
Hot-keys on this page
r m x p toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
|
# Natural Language Toolkit: Recursive Descent Parser Application # # Copyright (C) 2001-2012 NLTK Project # Author: Edward Loper <edloper@gradient.cis.upenn.edu> # URL: <http://www.nltk.org/> # For license information, see LICENSE.TXT
A graphical tool for exploring the recursive descent parser.
The recursive descent parser maintains a tree, which records the structure of the portion of the text that has been parsed. It uses CFG productions to expand the fringe of the tree, and matches its leaves against the text. Initially, the tree contains the start symbol ("S"). It is shown in the main canvas, to the right of the list of available expansions.
The parser builds up a tree structure for the text using three operations:
- "expand" uses a CFG production to add children to a node on the fringe of the tree. - "match" compares a leaf in the tree to a text token. - "backtrack" returns the tree to its state before the most recent expand or match operation.
The parser maintains a list of tree locations called a "frontier" to remember which nodes have not yet been expanded and which leaves have not yet been matched against the text. The leftmost frontier node is shown in green, and the other frontier nodes are shown in blue. The parser always performs expand and match operations on the leftmost element of the frontier.
You can control the parser's operation by using the "expand," "match," and "backtrack" buttons; or you can use the "step" button to let the parser automatically decide which operation to apply. The parser uses the following rules to decide which operation to apply:
- If the leftmost frontier element is a token, try matching it. - If the leftmost frontier element is a node, try expanding it with the first untried expansion. - Otherwise, backtrack.
The "expand" button applies the untried expansion whose CFG production is listed earliest in the grammar. To manually choose which expansion to apply, click on a CFG production from the list of available expansions, on the left side of the main window.
The "autostep" button will let the parser continue applying applications to the tree until it reaches a complete parse. You can cancel an autostep in progress at any time by clicking on the "autostep" button again.
Keyboard Shortcuts:: [Space]\t Perform the next expand, match, or backtrack operation [a]\t Step through operations until the next complete parse [e]\t Perform an expand operation [m]\t Perform a match operation [b]\t Perform a backtrack operation [Delete]\t Reset the parser [g]\t Show/hide available expansions list [h]\t Help [Ctrl-p]\t Print [q]\t Quit """
Frame, Label, Menu, Scrollbar, Tk)
""" A graphical tool for exploring the recursive descent parser. The tool displays the parser's tree and the remaining text, and allows the user to control the parser's operation. In particular, the user can expand subtrees on the frontier, match tokens on the frontier against the text, and backtrack. A "step" button simply steps through the parsing process, performing the operations that ``RecursiveDescentParser`` would use. """ self._sent = sent self._parser = SteppingRecursiveDescentParser(grammar, trace)
# Set up the main window. self._top = Tk() self._top.title('Recursive Descent Parser Application')
# Set up key bindings. self._init_bindings()
# Initialize the fonts. self._init_fonts(self._top)
# Animations. animating_lock is a lock to prevent the demo # from performing new operations while it's animating. self._animation_frames = IntVar(self._top) self._animation_frames.set(5) self._animating_lock = 0 self._autostep = 0
# The user can hide the grammar. self._show_grammar = IntVar(self._top) self._show_grammar.set(1)
# Create the basic frames. self._init_menubar(self._top) self._init_buttons(self._top) self._init_feedback(self._top) self._init_grammar(self._top) self._init_canvas(self._top)
# Initialize the parser. self._parser.initialize(self._sent)
# Resize callback self._canvas.bind('<Configure>', self._configure)
######################################### ## Initialization Helpers #########################################
# See: <http://www.astro.washington.edu/owen/ROTKFolklore.html> self._sysfont = tkFont.Font(font=Button()["font"]) root.option_add("*Font", self._sysfont)
# TWhat's our font size (default=same as sysfont) self._size = IntVar(root) self._size.set(self._sysfont.cget('size'))
self._boldfont = tkFont.Font(family='helvetica', weight='bold', size=self._size.get()) self._font = tkFont.Font(family='helvetica', size=self._size.get()) if self._size.get() < 0: big = self._size.get()-2 else: big = self._size.get()+2 self._bigfont = tkFont.Font(family='helvetica', weight='bold', size=big)
# Grammar view. self._prodframe = listframe = Frame(parent) self._prodframe.pack(fill='both', side='left', padx=2) self._prodlist_label = Label(self._prodframe, font=self._boldfont, text='Available Expansions') self._prodlist_label.pack() self._prodlist = Listbox(self._prodframe, selectmode='single', relief='groove', background='white', foreground='#909090', font=self._font, selectforeground='#004040', selectbackground='#c0f0c0')
self._prodlist.pack(side='right', fill='both', expand=1)
self._productions = list(self._parser.grammar().productions()) for production in self._productions: self._prodlist.insert('end', (' %s' % production)) self._prodlist.config(height=min(len(self._productions), 25))
# Add a scrollbar if there are more than 25 productions. if len(self._productions) > 25: listscroll = Scrollbar(self._prodframe, orient='vertical') self._prodlist.config(yscrollcommand = listscroll.set) listscroll.config(command=self._prodlist.yview) listscroll.pack(side='left', fill='y')
# If they select a production, apply it. self._prodlist.bind('<<ListboxSelect>>', self._prodlist_select)
# Key bindings are a good thing. self._top.bind('<Control-q>', self.destroy) self._top.bind('<Control-x>', self.destroy) self._top.bind('<Escape>', self.destroy) self._top.bind('e', self.expand) #self._top.bind('<Alt-e>', self.expand) #self._top.bind('<Control-e>', self.expand) self._top.bind('m', self.match) self._top.bind('<Alt-m>', self.match) self._top.bind('<Control-m>', self.match) self._top.bind('b', self.backtrack) self._top.bind('<Alt-b>', self.backtrack) self._top.bind('<Control-b>', self.backtrack) self._top.bind('<Control-z>', self.backtrack) self._top.bind('<BackSpace>', self.backtrack) self._top.bind('a', self.autostep) #self._top.bind('<Control-a>', self.autostep) self._top.bind('<Control-space>', self.autostep) self._top.bind('<Control-c>', self.cancel_autostep) self._top.bind('<space>', self.step) self._top.bind('<Delete>', self.reset) self._top.bind('<Control-p>', self.postscript) #self._top.bind('<h>', self.help) #self._top.bind('<Alt-h>', self.help) self._top.bind('<Control-h>', self.help) self._top.bind('<F1>', self.help) #self._top.bind('<g>', self.toggle_grammar) #self._top.bind('<Alt-g>', self.toggle_grammar) #self._top.bind('<Control-g>', self.toggle_grammar) self._top.bind('<Control-g>', self.edit_grammar) self._top.bind('<Control-t>', self.edit_sentence)
# Set up the frames. self._buttonframe = buttonframe = Frame(parent) buttonframe.pack(fill='none', side='bottom', padx=3, pady=2) Button(buttonframe, text='Step', background='#90c0d0', foreground='black', command=self.step,).pack(side='left') Button(buttonframe, text='Autostep', background='#90c0d0', foreground='black', command=self.autostep,).pack(side='left') Button(buttonframe, text='Expand', underline=0, background='#90f090', foreground='black', command=self.expand).pack(side='left') Button(buttonframe, text='Match', underline=0, background='#90f090', foreground='black', command=self.match).pack(side='left') Button(buttonframe, text='Backtrack', underline=0, background='#f0a0a0', foreground='black', command=self.backtrack).pack(side='left') # Replace autostep... # self._autostep_button = Button(buttonframe, text='Autostep', # underline=0, command=self.autostep) # self._autostep_button.pack(side='left')
self._autostep = 0 (x1, y1, x2, y2) = self._cframe.scrollregion() y2 = event.height - 6 self._canvas['scrollregion'] = '%d %d %d %d' % (x1,y1,x2,y2) self._redraw()
self._feedbackframe = feedbackframe = Frame(parent) feedbackframe.pack(fill='x', side='bottom', padx=3, pady=3) self._lastoper_label = Label(feedbackframe, text='Last Operation:', font=self._font) self._lastoper_label.pack(side='left') lastoperframe = Frame(feedbackframe, relief='sunken', border=1) lastoperframe.pack(fill='x', side='right', expand=1, padx=5) self._lastoper1 = Label(lastoperframe, foreground='#007070', background='#f0f0f0', font=self._font) self._lastoper2 = Label(lastoperframe, anchor='w', width=30, foreground='#004040', background='#f0f0f0', font=self._font) self._lastoper1.pack(side='left') self._lastoper2.pack(side='left', fill='x', expand=1)
self._cframe = CanvasFrame(parent, background='white', #width=525, height=250, closeenough=10, border=2, relief='sunken') self._cframe.pack(expand=1, fill='both', side='top', pady=2) canvas = self._canvas = self._cframe.canvas()
# Initially, there's no tree or text self._tree = None self._textwidgets = [] self._textline = None
menubar = Menu(parent)
filemenu = Menu(menubar, tearoff=0) filemenu.add_command(label='Reset Parser', underline=0, command=self.reset, accelerator='Del') filemenu.add_command(label='Print to Postscript', underline=0, command=self.postscript, accelerator='Ctrl-p') filemenu.add_command(label='Exit', underline=1, command=self.destroy, accelerator='Ctrl-x') menubar.add_cascade(label='File', underline=0, menu=filemenu)
editmenu = Menu(menubar, tearoff=0) editmenu.add_command(label='Edit Grammar', underline=5, command=self.edit_grammar, accelerator='Ctrl-g') editmenu.add_command(label='Edit Text', underline=5, command=self.edit_sentence, accelerator='Ctrl-t') menubar.add_cascade(label='Edit', underline=0, menu=editmenu)
rulemenu = Menu(menubar, tearoff=0) rulemenu.add_command(label='Step', underline=1, command=self.step, accelerator='Space') rulemenu.add_separator() rulemenu.add_command(label='Match', underline=0, command=self.match, accelerator='Ctrl-m') rulemenu.add_command(label='Expand', underline=0, command=self.expand, accelerator='Ctrl-e') rulemenu.add_separator() rulemenu.add_command(label='Backtrack', underline=0, command=self.backtrack, accelerator='Ctrl-b') 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 #########################################
for i in treeloc: widget = widget.subtrees()[i] if isinstance(widget, TreeSegmentWidget): widget = widget.node() return widget
######################################### ## Main draw procedure #########################################
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()
# This should be more-or-less sufficient after an animation. self._highlight_nodes() self._highlight_prodlist() self._position_text()
# 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'
# 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])
# 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().node().bbox()[3] - leaf.bbox()[3] + 10) leaf.move(0, dy)
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 #########################################
self._autostep = 0 if self._top is None: return self._top.destroy() self._top = None
self._autostep = 0 self._parser.initialize(self._sent) self._lastoper1['text'] = 'Reset Application' self._lastoper2['text'] = '' self._redraw()
if self._animation_frames.get() == 0: self._animation_frames.set(2) if self._autostep: self._autostep = 0 else: self._autostep = 1 self._step()
#self._autostep_button['text'] = 'Autostep' self._autostep = 0
# Make sure to stop auto-stepping if we get any user input.
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]'
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 1 else: self._lastoper1['text'] = 'Expand:' self._lastoper2['text'] = '(all expansions tried)' return 0
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 1 else: self._lastoper1['text'] = 'Match:' self._lastoper2['text'] = '(failed)' return 0
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 1 else: self._autostep = 0 self._lastoper1['text'] = 'Finished' self._lastoper2['text'] = '' return 0
ABOUT = ("NLTK Recursive Descent Parser Application\n"+ "Written by Edward Loper") TITLE = 'About: Recursive Descent Parser Application' try: from tkMessageBox import Message Message(message=ABOUT, title=TITLE).show() except: ShowText(self._top, TITLE, ABOUT)
self._autostep = 0 # The default font's not very legible; try using 'fixed' instead. try: ShowText(self._top, 'Help: Recursive Descent Parser Application', (__doc__).strip(), width=75, font='fixed') except: ShowText(self._top, 'Help: Recursive Descent Parser Application', (__doc__).strip(), width=75)
self._autostep = 0 self._cframe.print_to_file()
""" 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)
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 #########################################
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'] = ''
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 #########################################
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.node()['color'] = '#20a050'
(oldx, oldy) = oldtree.node().bbox()[:2] (newx, newy) = widget.node().bbox()[:2] widget.move(oldx-newx, oldy-newy)
if top: self._cframe.add_widget(widget, 0, 5) widget.move(30-widget.node().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.node().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)
""" 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)
if len(colors) > 0: self._animating_lock = 1 widget['color'] = colors[0] for subtree in widget.subtrees(): if isinstance(subtree, TreeSegmentWidget): subtree.node()['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.node()['color'] = 'black' else: subtree['color'] = 'black' self._redraw_quick() widget.node()['color'] = 'black' self._animating_lock = 0 if self._autostep: self._step()
# 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.node()) else: widgets.append(subtree)
self._animate_backtrack_frame(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()
widget = self._get(self._tree, treeloc) node = widget.parent().node() dy = (1.0 * (node.bbox()[3] - widget.bbox()[1] + 14) / max(1, self._animation_frames.get())) self._animate_match_backtrack_frame(self._animation_frames.get(), widget, dy)
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)
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()
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()
CFGEditor(self._top, self._parser.grammar(), self.set_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))
sentence = " ".join(self._sent) title = 'Edit Text' instr = 'Enter a new sentence to parse.' EntryDialog(self._top, sentence, instr, self.set_sentence, title)
self._sent = sentence.split() #[XX] use tagged? self.reset()
""" Create a recursive descent parser demo, using a simple grammar and text. """ from nltk.grammar import parse_cfg grammar = parse_cfg(""" # 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()
app()
|