def __init__(self, root):
""" Initialize user interface for the parser. """
self.root = root
self.grammar = Grammar()
self.lexicon = Lexicon()
self.root.title("Interactive Chart Parser")
self.mainframe = ttk.Frame(self.root, padding='3 3 12 12')
self.mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
self.mainframe.columnconfigure(0, weight=1)
self.mainframe.rowconfigure(0, weight=1)
ttk.Button(self.mainframe,
text='Show Lexicon',
width=15,
command=self.show_lexicon).grid(column=1, row=1, sticky=W)
ttk.Button(self.mainframe,
text='Show Grammar',
width=15,
command=self.show_grammar).grid(column=1, row=2, sticky=W)
ttk.Button(self.mainframe,
text='Add a Word',
width=15,
command=self.add_lexical_entry).grid(column=2,
row=1,
sticky=W)
ttk.Button(self.mainframe,
text='Add a Rule',
width=15,
command=self.add_grammar_rule).grid(column=2,
row=2,
sticky=W)
ttk.Button(self.mainframe,
text='Import Lexicon',
width=15,
command=self.import_lexicon).grid(column=3, row=1, sticky=W)
ttk.Button(self.mainframe,
text='Import Grammar',
width=15,
command=self.import_grammar).grid(column=3, row=2, sticky=W)
ttk.Button(self.mainframe,
text='Search for Word',
width=15,
command=self.search).grid(column=1, row=8, sticky=W)
self.sentence = ttk.Entry(self.mainframe, width=15)
self.sentence.grid(column=2, row=5, columnspan=2, sticky=(W, E))
ttk.Button(self.mainframe,
text='Parse',
width=15,
command=self.parse_sentence).grid(column=3, row=6, sticky=E)
ttk.Button(self.mainframe, text='Exit', width=10,
command=exit).grid(column=3, row=8, sticky=E)
ttk.Label(self.mainframe, text='Enter a sentence:').grid(column=1,
row=5,
sticky=E)
ttk.Label(self.mainframe, text='').grid(column=1, row=3, sticky=E)
ttk.Label(self.mainframe, text='').grid(column=1, row=7, sticky=E)
# add padding around every widget
for child in self.mainframe.winfo_children():
child.grid_configure(padx=5, pady=5)
# ensure user doesn't have to click first
self.sentence.focus()
def test_grammar_str():
grammar = Grammar()
grammar.load(StringIO(test_gram))
answer = [
"NP --> DT N",
"NP --> PN",
"S --> NP VP",
"VP --> V",
"VP --> V NP"]
answer = '\n'.join(answer)
result = str(grammar)
print(result)
assert result == answer
def test_grammar_add():
grammar = Grammar()
grammar.add(NonTerminal.from_string('np --> n'))
assert grammar['N'] == {NonTerminal('NP', 'N')}
grammar.add(NonTerminal('vp', 'v', 'np'))
assert grammar['V'] == {NonTerminal('VP', 'V', 'NP')}
grammar.add(NonTerminal('NP', 'N', 'Y'))
assert grammar['N'] == {
NonTerminal('NP', 'N'), NonTerminal('NP', 'N', 'Y')}
def __init__(self, grammar=Grammar(), lexicon=Lexicon()):
""" Initializes parser with grammar and lexicon.
Args:
grammar (Grammar) : Grammar object for parser
lexicon (Lexicon) : Lexicon object for parser
"""
self._grammar = grammar
self._lexicon = lexicon
def test_grammar_import():
grammar = Grammar()
grammar.load(StringIO(test_gram))
assert grammar['NP'] == {NonTerminal('S', 'NP', 'VP'), }
assert grammar['V'] == {
NonTerminal('VP', 'V'), NonTerminal('VP', 'V', 'NP')}
with pytest.raises(ValueError):
grammar.load(StringIO('S NP VP'))
class GUI:
def __init__(self, root):
""" Initialize user interface for the parser. """
self.root = root
self.grammar = Grammar()
self.lexicon = Lexicon()
self.root.title("Interactive Chart Parser")
self.mainframe = ttk.Frame(self.root, padding='3 3 12 12')
self.mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
self.mainframe.columnconfigure(0, weight=1)
self.mainframe.rowconfigure(0, weight=1)
ttk.Button(self.mainframe,
text='Show Lexicon',
width=15,
command=self.show_lexicon).grid(column=1, row=1, sticky=W)
ttk.Button(self.mainframe,
text='Show Grammar',
width=15,
command=self.show_grammar).grid(column=1, row=2, sticky=W)
ttk.Button(self.mainframe,
text='Add a Word',
width=15,
command=self.add_lexical_entry).grid(column=2,
row=1,
sticky=W)
ttk.Button(self.mainframe,
text='Add a Rule',
width=15,
command=self.add_grammar_rule).grid(column=2,
row=2,
sticky=W)
ttk.Button(self.mainframe,
text='Import Lexicon',
width=15,
command=self.import_lexicon).grid(column=3, row=1, sticky=W)
ttk.Button(self.mainframe,
text='Import Grammar',
width=15,
command=self.import_grammar).grid(column=3, row=2, sticky=W)
ttk.Button(self.mainframe,
text='Search for Word',
width=15,
command=self.search).grid(column=1, row=8, sticky=W)
self.sentence = ttk.Entry(self.mainframe, width=15)
self.sentence.grid(column=2, row=5, columnspan=2, sticky=(W, E))
ttk.Button(self.mainframe,
text='Parse',
width=15,
command=self.parse_sentence).grid(column=3, row=6, sticky=E)
ttk.Button(self.mainframe, text='Exit', width=10,
command=exit).grid(column=3, row=8, sticky=E)
ttk.Label(self.mainframe, text='Enter a sentence:').grid(column=1,
row=5,
sticky=E)
ttk.Label(self.mainframe, text='').grid(column=1, row=3, sticky=E)
ttk.Label(self.mainframe, text='').grid(column=1, row=7, sticky=E)
# add padding around every widget
for child in self.mainframe.winfo_children():
child.grid_configure(padx=5, pady=5)
# ensure user doesn't have to click first
self.sentence.focus()
def show_lexicon(self):
""" Show lexicon in window. """
self._show(self.lexicon)
def show_grammar(self):
""" Show grammar in window. """
self._show(self.grammar)
def _show(self, obj):
""" Show given object in window or display error
if the object is empty. """
if obj:
messagebox.showinfo(obj.name.upper(), self._truncate(str(obj)))
else:
messagebox.showerror('ERROR', 'No {}.'.format(obj.name))
def _truncate(self, string):
items = string.split('\n')
if len(items) <= 20:
return string
return '\n'.join(items[:20] + ['...'] + [items[-1]])
def parse_sentence(self):
""" Parse sentence that is currently in sentence textbox.
Displays a single possible parse in message window.
Displays error message if there are words in the sentence
that are not in the lexicon, or if there is no grammar imported,
or if no parse is found.
"""
if not self.sentence:
return
sentence = self.sentence.get()
parser = Parser(self.grammar, self.lexicon)
try:
parse = parser.parse(sentence)
except KeyError:
messagebox.showerror('ERROR', 'Unknown words or punctuation.')
except IndexError:
messagebox.showerror('ERROR', 'No grammar.')
except ValueError:
messagebox.showerror('ERROR', 'No parse.')
else:
messagebox.showinfo(sentence, parse)
def import_lexicon(self):
""" Import a lexicon. """
self._import(self.lexicon)
def import_grammar(self):
""" Import a grammar. """
self._import(self.grammar)
def _import(self, obj):
""" Import data for the given object. Shows error if the
object fails to load from a file specified by the user. """
file = filedialog.askopenfilename()
# user has cancelled
if not file:
return
with open(file, 'r') as f:
try:
obj.load(f)
except Exception as e:
messagebox.showerror(
'ERROR', 'Failed to load{}\n{}.'.format(obj.name, e))
def add_lexical_entry(self):
""" Prompts user to add a word and part of speech to the lexicon. """
try:
word = self._prompt('a word')
pos = self._prompt('a part of speech')
except ValueError:
return
word = word.strip().upper()
pos = pos.strip().upper()
self.lexicon.add(word, pos)
def add_grammar_rule(self):
""" Prompts user to add a rule to the grammar. """
try:
parent = self._prompt('the parent')
children = self._prompt('the children separated by spaces')
except ValueError:
return
try:
self.grammar.add(parent, children)
except ValueError:
messagebox.showerror('ERROR',
'Failed to add given rule to grammar.')
def _prompt(self, name):
""" Generic looped prompt to get user to give input.
Returns:
answer (str) : input from user
"""
prompt = "Please enter {}:".format(name)
while True:
answer = simpledialog.askstring(title="", prompt=prompt)
# user has cancelled
if answer is None:
raise ValueError
if answer.strip():
return answer
def search(self):
""" Searches lexicon for word provided by user. Shows part of
speech of word in message box if word is found otherwise shows
an error message. """
word = self._prompt('word')
if not word:
return
try:
pos = self.lexicon[word]
except KeyError:
messagebox.showerror('ERROR', '{} not found.'.format(word))
else:
messagebox.showinfo('POS for {}'.format(word.upper()),
', '.join(sorted(pos)))
def exit(self):
""" Exits program after prompting user to save
grammar and/or lexicon. """
for obj in self.lexicon, self.grammar:
message = "Would you like to save the {}?".format(obj.name)
if item and messagebox.askyesnocancel(message=message):
file = filedialog.asksaveasfilename()
with open(file, 'w') as f:
f.write(str(obj))
mainframe.quit()
def test_grammar_len():
grammar = Grammar()
assert not grammar
grammar.load(StringIO(test_gram))
assert grammar
assert len(grammar) == 5
def test_grammar_str():
grammar = Grammar()
grammar.load(StringIO(test_gram))
answer = [
"NP --> DT N",
"NP --> PN",
"S --> NP VP",
"VP --> V",
"VP --> V NP"]
answer = '\n'.join(answer)
result = str(grammar)
print(result)
assert result == answer
simple_grammar = Grammar()
simple_grammar.load(StringIO("""
S --> NP VP
NP --> PN
VP --> V
"""))
simple_lexicon = Lexicon()
simple_lexicon.load(StringIO("""
I : PN
sleep : V
"""))
simple_parser = Parser(simple_grammar, simple_lexicon)
simple_sentence = ' i sleep '
simple_tokens = ['I', 'SLEEP']
simple_parse = '[.S [.NP [.PN I]][.VP [.V SLEEP]]]'
simple_chart = [