def exploreCFG(cfg, length_limit): """ Generate strings with the CFG, without ever allowing an intermediate expression to exceed the length_limit. Note that not all strings with length <= length_limit that can be generated will be generated. For example, with S -> 1S | e and length_limit = 2, we won't be able to generate "11" because in the sequence S -> 1S -> 11S -> 11, 11S is too long and we would stop exploring there. """ cfg = CFG(cfg.start(), [splitProdRhs(prod) for prod in cfg.productions()]) finished = set() # Expressions with no nonterminals left visited = set( ) # Expressions with nonterminals that have already been explored to_explore = [(cfg.start(), )] while to_explore: expr = to_explore.pop() if expr in visited or len(expr) > length_limit: continue for i in range(len(expr)): if isinstance(expr[i], Nonterminal): break else: finished.add(expr) continue visited.add(expr) for prod in cfg.productions(lhs=expr[i]): to_explore.append(expr[:i] + prod.rhs() + expr[i + 1:]) return finished
class CFGEditor: """ A dialog window for creating and editing context free grammars. ``CFGEditor`` imposes the following restrictions: - All nonterminals must be strings consisting of word characters. - All terminals must be strings consisting of word characters and space characters. """ # Regular expressions used by _analyze_line. Precompile them, so # we can process the text faster. ARROW = SymbolWidget.SYMBOLS["rightarrow"] _LHS_RE = re.compile(r"(^\s*\w+\s*)(->|(" + ARROW + "))") _ARROW_RE = re.compile(r"\s*(->|(" + ARROW + r"))\s*") _PRODUCTION_RE = re.compile(r"(^\s*\w+\s*)" + "(->|(" # LHS + ARROW + r"))\s*" + r"((\w+|'[\w ]*'|\"[\w ]*\"|\|)\s*)*$" # arrow ) # RHS _TOKEN_RE = re.compile("\\w+|->|'[\\w ]+'|\"[\\w ]+\"|(" + ARROW + ")") _BOLD = ("helvetica", -12, "bold") def __init__(self, parent, cfg=None, set_cfg_callback=None): self._parent = parent if cfg is not None: self._cfg = cfg else: self._cfg = CFG(Nonterminal("S"), []) self._set_cfg_callback = set_cfg_callback self._highlight_matching_nonterminals = 1 # Create the top-level window. self._top = Toplevel(parent) self._init_bindings() self._init_startframe() self._startframe.pack(side="top", fill="x", expand=0) self._init_prodframe() self._prodframe.pack(side="top", fill="both", expand=1) self._init_buttons() self._buttonframe.pack(side="bottom", fill="x", expand=0) self._textwidget.focus() def _init_startframe(self): frame = self._startframe = Frame(self._top) self._start = Entry(frame) self._start.pack(side="right") Label(frame, text="Start Symbol:").pack(side="right") Label(frame, text="Productions:").pack(side="left") self._start.insert(0, self._cfg.start().symbol()) def _init_buttons(self): frame = self._buttonframe = Frame(self._top) Button(frame, text="Ok", command=self._ok, underline=0, takefocus=0).pack(side="left") Button(frame, text="Apply", command=self._apply, underline=0, takefocus=0).pack(side="left") Button(frame, text="Reset", command=self._reset, underline=0, takefocus=0).pack(side="left") Button(frame, text="Cancel", command=self._cancel, underline=0, takefocus=0).pack(side="left") Button(frame, text="Help", command=self._help, underline=0, takefocus=0).pack(side="right") def _init_bindings(self): self._top.title("CFG Editor") self._top.bind("<Control-q>", self._cancel) self._top.bind("<Alt-q>", self._cancel) self._top.bind("<Control-d>", self._cancel) # self._top.bind('<Control-x>', self._cancel) self._top.bind("<Alt-x>", self._cancel) self._top.bind("<Escape>", self._cancel) # self._top.bind('<Control-c>', self._cancel) self._top.bind("<Alt-c>", self._cancel) self._top.bind("<Control-o>", self._ok) self._top.bind("<Alt-o>", self._ok) self._top.bind("<Control-a>", self._apply) self._top.bind("<Alt-a>", self._apply) self._top.bind("<Control-r>", self._reset) self._top.bind("<Alt-r>", self._reset) self._top.bind("<Control-h>", self._help) self._top.bind("<Alt-h>", self._help) self._top.bind("<F1>", self._help) def _init_prodframe(self): self._prodframe = Frame(self._top) # Create the basic Text widget & scrollbar. self._textwidget = Text(self._prodframe, background="#e0e0e0", exportselection=1) self._textscroll = Scrollbar(self._prodframe, takefocus=0, orient="vertical") self._textwidget.config(yscrollcommand=self._textscroll.set) self._textscroll.config(command=self._textwidget.yview) self._textscroll.pack(side="right", fill="y") self._textwidget.pack(expand=1, fill="both", side="left") # Initialize the colorization tags. Each nonterminal gets its # own tag, so they aren't listed here. self._textwidget.tag_config("terminal", foreground="#006000") self._textwidget.tag_config("arrow", font="symbol") self._textwidget.tag_config("error", background="red") # Keep track of what line they're on. We use that to remember # to re-analyze a line whenever they leave it. self._linenum = 0 # Expand "->" to an arrow. self._top.bind(">", self._replace_arrows) # Re-colorize lines when appropriate. self._top.bind("<<Paste>>", self._analyze) self._top.bind("<KeyPress>", self._check_analyze) self._top.bind("<ButtonPress>", self._check_analyze) # Tab cycles focus. (why doesn't this work??) def cycle(e, textwidget=self._textwidget): textwidget.tk_focusNext().focus() self._textwidget.bind("<Tab>", cycle) prod_tuples = [(p.lhs(), [p.rhs()]) for p in self._cfg.productions()] for i in range(len(prod_tuples) - 1, 0, -1): if prod_tuples[i][0] == prod_tuples[i - 1][0]: if () in prod_tuples[i][1]: continue if () in prod_tuples[i - 1][1]: continue print(prod_tuples[i - 1][1]) print(prod_tuples[i][1]) prod_tuples[i - 1][1].extend(prod_tuples[i][1]) del prod_tuples[i] for lhs, rhss in prod_tuples: print(lhs, rhss) s = "%s ->" % lhs for rhs in rhss: for elt in rhs: if isinstance(elt, Nonterminal): s += " %s" % elt else: s += " %r" % elt s += " |" s = s[:-2] + "\n" self._textwidget.insert("end", s) self._analyze() # # Add the producitons to the text widget, and colorize them. # prod_by_lhs = {} # for prod in self._cfg.productions(): # if len(prod.rhs()) > 0: # prod_by_lhs.setdefault(prod.lhs(),[]).append(prod) # for (lhs, prods) in prod_by_lhs.items(): # self._textwidget.insert('end', '%s ->' % lhs) # self._textwidget.insert('end', self._rhs(prods[0])) # for prod in prods[1:]: # print '\t|'+self._rhs(prod), # self._textwidget.insert('end', '\t|'+self._rhs(prod)) # print # self._textwidget.insert('end', '\n') # for prod in self._cfg.productions(): # if len(prod.rhs()) == 0: # self._textwidget.insert('end', '%s' % prod) # self._analyze() # def _rhs(self, prod): # s = '' # for elt in prod.rhs(): # if isinstance(elt, Nonterminal): s += ' %s' % elt.symbol() # else: s += ' %r' % elt # return s def _clear_tags(self, linenum): """ Remove all tags (except ``arrow`` and ``sel``) from the given line of the text widget used for editing the productions. """ start = "%d.0" % linenum end = "%d.end" % linenum for tag in self._textwidget.tag_names(): if tag not in ("arrow", "sel"): self._textwidget.tag_remove(tag, start, end) def _check_analyze(self, *e): """ Check if we've moved to a new line. If we have, then remove all colorization from the line we moved to, and re-colorize the line that we moved from. """ linenum = int(self._textwidget.index("insert").split(".")[0]) if linenum != self._linenum: self._clear_tags(linenum) self._analyze_line(self._linenum) self._linenum = linenum def _replace_arrows(self, *e): """ Replace any ``'->'`` text strings with arrows (char \\256, in symbol font). This searches the whole buffer, but is fast enough to be done anytime they press '>'. """ arrow = "1.0" while True: arrow = self._textwidget.search("->", arrow, "end+1char") if arrow == "": break self._textwidget.delete(arrow, arrow + "+2char") self._textwidget.insert(arrow, self.ARROW, "arrow") self._textwidget.insert(arrow, "\t") arrow = "1.0" while True: arrow = self._textwidget.search(self.ARROW, arrow + "+1char", "end+1char") if arrow == "": break self._textwidget.tag_add("arrow", arrow, arrow + "+1char") def _analyze_token(self, match, linenum): """ Given a line number and a regexp match for a token on that line, colorize the token. Note that the regexp match gives us the token's text, start index (on the line), and end index (on the line). """ # What type of token is it? if match.group()[0] in "'\"": tag = "terminal" elif match.group() in ("->", self.ARROW): tag = "arrow" else: # If it's a nonterminal, then set up new bindings, so we # can highlight all instances of that nonterminal when we # put the mouse over it. tag = "nonterminal_" + match.group() if tag not in self._textwidget.tag_names(): self._init_nonterminal_tag(tag) start = "%d.%d" % (linenum, match.start()) end = "%d.%d" % (linenum, match.end()) self._textwidget.tag_add(tag, start, end) def _init_nonterminal_tag(self, tag, foreground="blue"): self._textwidget.tag_config(tag, foreground=foreground, font=CFGEditor._BOLD) if not self._highlight_matching_nonterminals: return def enter(e, textwidget=self._textwidget, tag=tag): textwidget.tag_config(tag, background="#80ff80") def leave(e, textwidget=self._textwidget, tag=tag): textwidget.tag_config(tag, background="") self._textwidget.tag_bind(tag, "<Enter>", enter) self._textwidget.tag_bind(tag, "<Leave>", leave) def _analyze_line(self, linenum): """ Colorize a given line. """ # Get rid of any tags that were previously on the line. self._clear_tags(linenum) # Get the line line's text string. line = self._textwidget.get( repr(linenum) + ".0", repr(linenum) + ".end") # If it's a valid production, then colorize each token. if CFGEditor._PRODUCTION_RE.match(line): # It's valid; Use _TOKEN_RE to tokenize the production, # and call analyze_token on each token. def analyze_token(match, self=self, linenum=linenum): self._analyze_token(match, linenum) return "" CFGEditor._TOKEN_RE.sub(analyze_token, line) elif line.strip() != "": # It's invalid; show the user where the error is. self._mark_error(linenum, line) def _mark_error(self, linenum, line): """ Mark the location of an error in a line. """ arrowmatch = CFGEditor._ARROW_RE.search(line) if not arrowmatch: # If there's no arrow at all, highlight the whole line. start = "%d.0" % linenum end = "%d.end" % linenum elif not CFGEditor._LHS_RE.match(line): # Otherwise, if the LHS is bad, highlight it. start = "%d.0" % linenum end = "%d.%d" % (linenum, arrowmatch.start()) else: # Otherwise, highlight the RHS. start = "%d.%d" % (linenum, arrowmatch.end()) end = "%d.end" % linenum # If we're highlighting 0 chars, highlight the whole line. if self._textwidget.compare(start, "==", end): start = "%d.0" % linenum end = "%d.end" % linenum self._textwidget.tag_add("error", start, end) def _analyze(self, *e): """ Replace ``->`` with arrows, and colorize the entire buffer. """ self._replace_arrows() numlines = int(self._textwidget.index("end").split(".")[0]) for linenum in range(1, numlines + 1): # line numbers start at 1. self._analyze_line(linenum) def _parse_productions(self): """ Parse the current contents of the textwidget buffer, to create a list of productions. """ productions = [] # Get the text, normalize it, and split it into lines. text = self._textwidget.get("1.0", "end") text = re.sub(self.ARROW, "->", text) text = re.sub("\t", " ", text) lines = text.split("\n") # Convert each line to a CFG production for line in lines: line = line.strip() if line == "": continue productions += _read_cfg_production(line) # if line.strip() == '': continue # if not CFGEditor._PRODUCTION_RE.match(line): # raise ValueError('Bad production string %r' % line) # # (lhs_str, rhs_str) = line.split('->') # lhs = Nonterminal(lhs_str.strip()) # rhs = [] # def parse_token(match, rhs=rhs): # token = match.group() # if token[0] in "'\"": rhs.append(token[1:-1]) # else: rhs.append(Nonterminal(token)) # return '' # CFGEditor._TOKEN_RE.sub(parse_token, rhs_str) # # productions.append(Production(lhs, *rhs)) return productions def _destroy(self, *e): if self._top is None: return self._top.destroy() self._top = None def _ok(self, *e): self._apply() self._destroy() def _apply(self, *e): productions = self._parse_productions() start = Nonterminal(self._start.get()) cfg = CFG(start, productions) if self._set_cfg_callback is not None: self._set_cfg_callback(cfg) def _reset(self, *e): self._textwidget.delete("1.0", "end") for production in self._cfg.productions(): self._textwidget.insert("end", "%s\n" % production) self._analyze() if self._set_cfg_callback is not None: self._set_cfg_callback(self._cfg) def _cancel(self, *e): try: self._reset() except: pass self._destroy() def _help(self, *e): # The default font's not very legible; try using 'fixed' instead. try: ShowText( self._parent, "Help: Chart Parser Demo", (_CFGEditor_HELP).strip(), width=75, font="fixed", ) except: ShowText( self._parent, "Help: Chart Parser Demo", (_CFGEditor_HELP).strip(), width=75, )
class CFGEditor(object): """ A dialog window for creating and editing context free grammars. ``CFGEditor`` imposes the following restrictions: - All nonterminals must be strings consisting of word characters. - All terminals must be strings consisting of word characters and space characters. """ # Regular expressions used by _analyze_line. Precompile them, so # we can process the text faster. ARROW = SymbolWidget.SYMBOLS['rightarrow'] _LHS_RE = re.compile(r"(^\s*\w+\s*)(->|(" + ARROW + "))") _ARROW_RE = re.compile("\s*(->|(" + ARROW + "))\s*") _PRODUCTION_RE = re.compile( r"(^\s*\w+\s*)" + "(->|(" # LHS + ARROW + "))\s*" + r"((\w+|'[\w ]*'|\"[\w ]*\"|\|)\s*)*$" # arrow ) # RHS _TOKEN_RE = re.compile("\\w+|->|'[\\w ]+'|\"[\\w ]+\"|(" + ARROW + ")") _BOLD = ('helvetica', -12, 'bold') def __init__(self, parent, cfg=None, set_cfg_callback=None): self._parent = parent if cfg is not None: self._cfg = cfg else: self._cfg = CFG(Nonterminal('S'), []) self._set_cfg_callback = set_cfg_callback self._highlight_matching_nonterminals = 1 # Create the top-level window. self._top = Toplevel(parent) self._init_bindings() self._init_startframe() self._startframe.pack(side='top', fill='x', expand=0) self._init_prodframe() self._prodframe.pack(side='top', fill='both', expand=1) self._init_buttons() self._buttonframe.pack(side='bottom', fill='x', expand=0) self._textwidget.focus() def _init_startframe(self): frame = self._startframe = Frame(self._top) self._start = Entry(frame) self._start.pack(side='right') Label(frame, text='Start Symbol:').pack(side='right') Label(frame, text='Productions:').pack(side='left') self._start.insert(0, self._cfg.start().symbol()) def _init_buttons(self): frame = self._buttonframe = Frame(self._top) Button(frame, text='Ok', command=self._ok, underline=0, takefocus=0).pack( side='left' ) Button(frame, text='Apply', command=self._apply, underline=0, takefocus=0).pack( side='left' ) Button(frame, text='Reset', command=self._reset, underline=0, takefocus=0).pack( side='left' ) Button( frame, text='Cancel', command=self._cancel, underline=0, takefocus=0 ).pack(side='left') Button(frame, text='Help', command=self._help, underline=0, takefocus=0).pack( side='right' ) def _init_bindings(self): self._top.title('CFG Editor') self._top.bind('<Control-q>', self._cancel) self._top.bind('<Alt-q>', self._cancel) self._top.bind('<Control-d>', self._cancel) # self._top.bind('<Control-x>', self._cancel) self._top.bind('<Alt-x>', self._cancel) self._top.bind('<Escape>', self._cancel) # self._top.bind('<Control-c>', self._cancel) self._top.bind('<Alt-c>', self._cancel) self._top.bind('<Control-o>', self._ok) self._top.bind('<Alt-o>', self._ok) self._top.bind('<Control-a>', self._apply) self._top.bind('<Alt-a>', self._apply) self._top.bind('<Control-r>', self._reset) self._top.bind('<Alt-r>', self._reset) self._top.bind('<Control-h>', self._help) self._top.bind('<Alt-h>', self._help) self._top.bind('<F1>', self._help) def _init_prodframe(self): self._prodframe = Frame(self._top) # Create the basic Text widget & scrollbar. self._textwidget = Text( self._prodframe, background='#e0e0e0', exportselection=1 ) self._textscroll = Scrollbar(self._prodframe, takefocus=0, orient='vertical') self._textwidget.config(yscrollcommand=self._textscroll.set) self._textscroll.config(command=self._textwidget.yview) self._textscroll.pack(side='right', fill='y') self._textwidget.pack(expand=1, fill='both', side='left') # Initialize the colorization tags. Each nonterminal gets its # own tag, so they aren't listed here. self._textwidget.tag_config('terminal', foreground='#006000') self._textwidget.tag_config('arrow', font='symbol') self._textwidget.tag_config('error', background='red') # Keep track of what line they're on. We use that to remember # to re-analyze a line whenever they leave it. self._linenum = 0 # Expand "->" to an arrow. self._top.bind('>', self._replace_arrows) # Re-colorize lines when appropriate. self._top.bind('<<Paste>>', self._analyze) self._top.bind('<KeyPress>', self._check_analyze) self._top.bind('<ButtonPress>', self._check_analyze) # Tab cycles focus. (why doesn't this work??) def cycle(e, textwidget=self._textwidget): textwidget.tk_focusNext().focus() self._textwidget.bind('<Tab>', cycle) prod_tuples = [(p.lhs(), [p.rhs()]) for p in self._cfg.productions()] for i in range(len(prod_tuples) - 1, 0, -1): if prod_tuples[i][0] == prod_tuples[i - 1][0]: if () in prod_tuples[i][1]: continue if () in prod_tuples[i - 1][1]: continue print(prod_tuples[i - 1][1]) print(prod_tuples[i][1]) prod_tuples[i - 1][1].extend(prod_tuples[i][1]) del prod_tuples[i] for lhs, rhss in prod_tuples: print(lhs, rhss) s = '%s ->' % lhs for rhs in rhss: for elt in rhs: if isinstance(elt, Nonterminal): s += ' %s' % elt else: s += ' %r' % elt s += ' |' s = s[:-2] + '\n' self._textwidget.insert('end', s) self._analyze() # # Add the producitons to the text widget, and colorize them. # prod_by_lhs = {} # for prod in self._cfg.productions(): # if len(prod.rhs()) > 0: # prod_by_lhs.setdefault(prod.lhs(),[]).append(prod) # for (lhs, prods) in prod_by_lhs.items(): # self._textwidget.insert('end', '%s ->' % lhs) # self._textwidget.insert('end', self._rhs(prods[0])) # for prod in prods[1:]: # print '\t|'+self._rhs(prod), # self._textwidget.insert('end', '\t|'+self._rhs(prod)) # print # self._textwidget.insert('end', '\n') # for prod in self._cfg.productions(): # if len(prod.rhs()) == 0: # self._textwidget.insert('end', '%s' % prod) # self._analyze() # def _rhs(self, prod): # s = '' # for elt in prod.rhs(): # if isinstance(elt, Nonterminal): s += ' %s' % elt.symbol() # else: s += ' %r' % elt # return s def _clear_tags(self, linenum): """ Remove all tags (except ``arrow`` and ``sel``) from the given line of the text widget used for editing the productions. """ start = '%d.0' % linenum end = '%d.end' % linenum for tag in self._textwidget.tag_names(): if tag not in ('arrow', 'sel'): self._textwidget.tag_remove(tag, start, end) def _check_analyze(self, *e): """ Check if we've moved to a new line. If we have, then remove all colorization from the line we moved to, and re-colorize the line that we moved from. """ linenum = int(self._textwidget.index('insert').split('.')[0]) if linenum != self._linenum: self._clear_tags(linenum) self._analyze_line(self._linenum) self._linenum = linenum def _replace_arrows(self, *e): """ Replace any ``'->'`` text strings with arrows (char \\256, in symbol font). This searches the whole buffer, but is fast enough to be done anytime they press '>'. """ arrow = '1.0' while True: arrow = self._textwidget.search('->', arrow, 'end+1char') if arrow == '': break self._textwidget.delete(arrow, arrow + '+2char') self._textwidget.insert(arrow, self.ARROW, 'arrow') self._textwidget.insert(arrow, '\t') arrow = '1.0' while True: arrow = self._textwidget.search(self.ARROW, arrow + '+1char', 'end+1char') if arrow == '': break self._textwidget.tag_add('arrow', arrow, arrow + '+1char') def _analyze_token(self, match, linenum): """ Given a line number and a regexp match for a token on that line, colorize the token. Note that the regexp match gives us the token's text, start index (on the line), and end index (on the line). """ # What type of token is it? if match.group()[0] in "'\"": tag = 'terminal' elif match.group() in ('->', self.ARROW): tag = 'arrow' else: # If it's a nonterminal, then set up new bindings, so we # can highlight all instances of that nonterminal when we # put the mouse over it. tag = 'nonterminal_' + match.group() if tag not in self._textwidget.tag_names(): self._init_nonterminal_tag(tag) start = '%d.%d' % (linenum, match.start()) end = '%d.%d' % (linenum, match.end()) self._textwidget.tag_add(tag, start, end) def _init_nonterminal_tag(self, tag, foreground='blue'): self._textwidget.tag_config(tag, foreground=foreground, font=CFGEditor._BOLD) if not self._highlight_matching_nonterminals: return def enter(e, textwidget=self._textwidget, tag=tag): textwidget.tag_config(tag, background='#80ff80') def leave(e, textwidget=self._textwidget, tag=tag): textwidget.tag_config(tag, background='') self._textwidget.tag_bind(tag, '<Enter>', enter) self._textwidget.tag_bind(tag, '<Leave>', leave) def _analyze_line(self, linenum): """ Colorize a given line. """ # Get rid of any tags that were previously on the line. self._clear_tags(linenum) # Get the line line's text string. line = self._textwidget.get(repr(linenum) + '.0', repr(linenum) + '.end') # If it's a valid production, then colorize each token. if CFGEditor._PRODUCTION_RE.match(line): # It's valid; Use _TOKEN_RE to tokenize the production, # and call analyze_token on each token. def analyze_token(match, self=self, linenum=linenum): self._analyze_token(match, linenum) return '' CFGEditor._TOKEN_RE.sub(analyze_token, line) elif line.strip() != '': # It's invalid; show the user where the error is. self._mark_error(linenum, line) def _mark_error(self, linenum, line): """ Mark the location of an error in a line. """ arrowmatch = CFGEditor._ARROW_RE.search(line) if not arrowmatch: # If there's no arrow at all, highlight the whole line. start = '%d.0' % linenum end = '%d.end' % linenum elif not CFGEditor._LHS_RE.match(line): # Otherwise, if the LHS is bad, highlight it. start = '%d.0' % linenum end = '%d.%d' % (linenum, arrowmatch.start()) else: # Otherwise, highlight the RHS. start = '%d.%d' % (linenum, arrowmatch.end()) end = '%d.end' % linenum # If we're highlighting 0 chars, highlight the whole line. if self._textwidget.compare(start, '==', end): start = '%d.0' % linenum end = '%d.end' % linenum self._textwidget.tag_add('error', start, end) def _analyze(self, *e): """ Replace ``->`` with arrows, and colorize the entire buffer. """ self._replace_arrows() numlines = int(self._textwidget.index('end').split('.')[0]) for linenum in range(1, numlines + 1): # line numbers start at 1. self._analyze_line(linenum) def _parse_productions(self): """ Parse the current contents of the textwidget buffer, to create a list of productions. """ productions = [] # Get the text, normalize it, and split it into lines. text = self._textwidget.get('1.0', 'end') text = re.sub(self.ARROW, '->', text) text = re.sub('\t', ' ', text) lines = text.split('\n') # Convert each line to a CFG production for line in lines: line = line.strip() if line == '': continue productions += _read_cfg_production(line) # if line.strip() == '': continue # if not CFGEditor._PRODUCTION_RE.match(line): # raise ValueError('Bad production string %r' % line) # # (lhs_str, rhs_str) = line.split('->') # lhs = Nonterminal(lhs_str.strip()) # rhs = [] # def parse_token(match, rhs=rhs): # token = match.group() # if token[0] in "'\"": rhs.append(token[1:-1]) # else: rhs.append(Nonterminal(token)) # return '' # CFGEditor._TOKEN_RE.sub(parse_token, rhs_str) # # productions.append(Production(lhs, *rhs)) return productions def _destroy(self, *e): if self._top is None: return self._top.destroy() self._top = None def _ok(self, *e): self._apply() self._destroy() def _apply(self, *e): productions = self._parse_productions() start = Nonterminal(self._start.get()) cfg = CFG(start, productions) if self._set_cfg_callback is not None: self._set_cfg_callback(cfg) def _reset(self, *e): self._textwidget.delete('1.0', 'end') for production in self._cfg.productions(): self._textwidget.insert('end', '%s\n' % production) self._analyze() if self._set_cfg_callback is not None: self._set_cfg_callback(self._cfg) def _cancel(self, *e): try: self._reset() except: pass self._destroy() def _help(self, *e): # The default font's not very legible; try using 'fixed' instead. try: ShowText( self._parent, 'Help: Chart Parser Demo', (_CFGEditor_HELP).strip(), width=75, font='fixed', ) except: ShowText( self._parent, 'Help: Chart Parser Demo', (_CFGEditor_HELP).strip(), width=75, )
stimtrees.append( ("(ROOT" + m, num) ) # add ROOT tag back at the beginning of the tree, and output a tuple with tree and the stimulus ID (num) """Fix up the last tree in stimulus 0.. stimulus 0 excluded the last IU (="stating that") in the speaker's turn, to make it fit with the desired IU count. Those two words were included in the text given to the parser in case the omission would have caused the parser difficulty, but we don't want to include them in our analysis since the subjects didn't actually hear them.. I removed those two words from the stanford parse tree text file that we read in earlier, but now I need to add in the final parentheses to make the parse processable by the Tree function """ stimtrees[5] = (stimtrees[5][0] + ")))))))\n(. ?))\n(. .)))\n\n", stimtrees[5][1]) processed_trees = [ Tree.fromstring(tree[0]) for tree in stimtrees ] # create Tree structure and viewable tree image for each tree processed_trees[0] # shows tree image for stimulus 0 # prods=[t.productions() for t in processed_trees] rules = reduce(lambda x, y: x + y, [t.productions() for t in processed_trees]) mycfg = CFG(Nonterminal("ROOT"), rules) mycfg.start() mycfg.productions( lhs=Nonterminal("PP") ) # Will print productions for the specified nonterminal item (e.g. "PP", a prepositional phrase), where the PP is the left-hand side of the rule (e.g. PP -> whatever) #%% # ============================================================================== # Loop through Production rules to extract Syntactic Tags and Terminal Words, keep track of Clause boundaries by looking for the first word appearing after an "S" tag # ============================================================================== words = [] counter = 0 tags = [] ruleset = [] ClauseBoundary = ( False ) # below, this variable will be set to TRUE if the rule begins with 'S' (clause boundary), or FALSE the rule contains a terminal