def test_load(self):
buf = io.StringIO("""
E -> T E'
E' -> + T E' | &
T -> F T'
T' -> * F T' | &
F -> ( E ) | id
""")
cfg = CFG.load(buf)
self.assertEqual('E', cfg.initial_symbol)
self.assertDictEqual({
'E': {"T E'"},
"E'": {"+ T E'", '&'},
'T': {"F T'"},
"T'": {"* F T'", '&'},
'F': {'( E )', 'id'}
}, cfg.productions)
buf = io.StringIO('')
with self.assertRaises(ValueError):
CFG.load(buf)
buf = io.StringIO("""
S ->
""")
with self.assertRaises(ValueError):
CFG.load(buf)
def update_grammar(self):
'''Updates grammar with given input and then updates UI.
If it fails to generate the grammar, nothing happens.'''
try:
self.grammar = CFG.load(self.editor.toPlainText().splitlines())
except Exception as e:
traceback.print_tb(e.__traceback__)
self.window.statusBar().showMessage(
'Failed to generate grammar. Check your syntax.')
#self.make_proper_item.setEnabled(False)
#self.parse_table_item.setEnabled(False)
return
self.window.statusBar().showMessage('Done.')
self.make_proper_item.setEnabled(True)
self.parse_table_item.setEnabled(True)
self.run_grammar_btn.setEnabled(False)
try:
self.update_tables()
except RecursionError as e:
self.window.statusBar().showMessage(
'Failed to generate grammar tables: Recursion depth overflow.')
#self.make_proper_item.setEnabled(False)
#self.parse_table_item.setEnabled(False)
return