| """A generic class to build line-oriented command interpreters. | |
| Interpreters constructed with this class obey the following conventions: | |
| 1. End of file on input is processed as the command 'EOF'. | |
| 2. A command is parsed out of each line by collecting the prefix composed | |
| of characters in the identchars member. | |
| 3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method | |
| is passed a single argument consisting of the remainder of the line. | |
| 4. Typing an empty line repeats the last command. (Actually, it calls the | |
| method `emptyline', which may be overridden in a subclass.) | |
| 5. There is a predefined `help' method. Given an argument `topic', it | |
| calls the command `help_topic'. With no arguments, it lists all topics | |
| with defined help_ functions, broken into up to three topics; documented | |
| commands, miscellaneous help topics, and undocumented commands. | |
| 6. The command '?' is a synonym for `help'. The command '!' is a synonym | |
| for `shell', if a do_shell method exists. | |
| 7. If completion is enabled, completing commands will be done automatically, | |
| and completing of commands args is done by calling complete_foo() with | |
| arguments text, line, begidx, endidx. text is string we are matching | |
| against, all returned matches must begin with it. line is the current | |
| input line (lstripped), begidx and endidx are the beginning and end | |
| indexes of the text being matched, which could be used to provide | |
| different completion depending upon which position the argument is in. | |
| The `default' method may be overridden to intercept commands for which there | |
| is no do_ method. | |
| The `completedefault' method may be overridden to intercept completions for | |
| commands that have no complete_ method. | |
| The data member `self.ruler' sets the character used to draw separator lines | |
| in the help messages. If empty, no ruler line is drawn. It defaults to "=". | |
| If the value of `self.intro' is nonempty when the cmdloop method is called, | |
| it is printed out on interpreter startup. This value may be overridden | |
| via an optional argument to the cmdloop() method. | |
| The data members `self.doc_header', `self.misc_header', and | |
| `self.undoc_header' set the headers used for the help function's | |
| listings of documented functions, miscellaneous topics, and undocumented | |
| functions respectively. | |
| These interpreters use raw_input; thus, if the readline module is loaded, | |
| they automatically support Emacs-like command history and editing features. | |
| """ | |
| import string | |
| __all__ = ["Cmd"] | |
| PROMPT = '(Cmd) ' | |
| IDENTCHARS = string.ascii_letters + string.digits + '_' | |
| class Cmd: | |
| """A simple framework for writing line-oriented command interpreters. | |
| These are often useful for test harnesses, administrative tools, and | |
| prototypes that will later be wrapped in a more sophisticated interface. | |
| A Cmd instance or subclass instance is a line-oriented interpreter | |
| framework. There is no good reason to instantiate Cmd itself; rather, | |
| it's useful as a superclass of an interpreter class you define yourself | |
| in order to inherit Cmd's methods and encapsulate action methods. | |
| """ | |
| prompt = PROMPT | |
| identchars = IDENTCHARS | |
| ruler = '=' | |
| lastcmd = '' | |
| intro = None | |
| doc_leader = "" | |
| doc_header = "Documented commands (type help <topic>):" | |
| misc_header = "Miscellaneous help topics:" | |
| undoc_header = "Undocumented commands:" | |
| nohelp = "*** No help on %s" | |
| use_rawinput = 1 | |
| def __init__(self, completekey='tab', stdin=None, stdout=None): | |
| """Instantiate a line-oriented interpreter framework. | |
| The optional argument 'completekey' is the readline name of a | |
| completion key; it defaults to the Tab key. If completekey is | |
| not None and the readline module is available, command completion | |
| is done automatically. The optional arguments stdin and stdout | |
| specify alternate input and output file objects; if not specified, | |
| sys.stdin and sys.stdout are used. | |
| """ | |
| import sys | |
| if stdin is not None: | |
| self.stdin = stdin | |
| else: | |
| self.stdin = sys.stdin | |
| if stdout is not None: | |
| self.stdout = stdout | |
| else: | |
| self.stdout = sys.stdout | |
| self.cmdqueue = [] | |
| self.completekey = completekey | |
| def cmdloop(self, intro=None): | |
| """Repeatedly issue a prompt, accept input, parse an initial prefix | |
| off the received input, and dispatch to action methods, passing them | |
| the remainder of the line as argument. | |
| """ | |
| self.preloop() | |
| if self.use_rawinput and self.completekey: | |
| try: | |
| import readline | |
| self.old_completer = readline.get_completer() | |
| readline.set_completer(self.complete) | |
| readline.parse_and_bind(self.completekey+": complete") | |
| except ImportError: | |
| pass | |
| try: | |
| if intro is not None: | |
| self.intro = intro | |
| if self.intro: | |
| self.stdout.write(str(self.intro)+"\n") | |
| stop = None | |
| while not stop: | |
| if self.cmdqueue: | |
| line = self.cmdqueue.pop(0) | |
| else: | |
| if self.use_rawinput: | |
| try: | |
| line = raw_input(self.prompt) | |
| except EOFError: | |
| line = 'EOF' | |
| else: | |
| self.stdout.write(self.prompt) | |
| self.stdout.flush() | |
| line = self.stdin.readline() | |
| if not len(line): | |
| line = 'EOF' | |
| else: | |
| line = line.rstrip('\r\n') | |
| line = self.precmd(line) | |
| stop = self.onecmd(line) | |
| stop = self.postcmd(stop, line) | |
| self.postloop() | |
| finally: | |
| if self.use_rawinput and self.completekey: | |
| try: | |
| import readline | |
| readline.set_completer(self.old_completer) | |
| except ImportError: | |
| pass | |
| def precmd(self, line): | |
| """Hook method executed just before the command line is | |
| interpreted, but after the input prompt is generated and issued. | |
| """ | |
| return line | |
| def postcmd(self, stop, line): | |
| """Hook method executed just after a command dispatch is finished.""" | |
| return stop | |
| def preloop(self): | |
| """Hook method executed once when the cmdloop() method is called.""" | |
| pass | |
| def postloop(self): | |
| """Hook method executed once when the cmdloop() method is about to | |
| return. | |
| """ | |
| pass | |
| def parseline(self, line): | |
| """Parse the line into a command name and a string containing | |
| the arguments. Returns a tuple containing (command, args, line). | |
| 'command' and 'args' may be None if the line couldn't be parsed. | |
| """ | |
| line = line.strip() | |
| if not line: | |
| return None, None, line | |
| elif line[0] == '?': | |
| line = 'help ' + line[1:] | |
| elif line[0] == '!': | |
| if hasattr(self, 'do_shell'): | |
| line = 'shell ' + line[1:] | |
| else: | |
| return None, None, line | |
| i, n = 0, len(line) | |
| while i < n and line[i] in self.identchars: i = i+1 | |
| cmd, arg = line[:i], line[i:].strip() | |
| return cmd, arg, line | |
| def onecmd(self, line): | |
| """Interpret the argument as though it had been typed in response | |
| to the prompt. | |
| This may be overridden, but should not normally need to be; | |
| see the precmd() and postcmd() methods for useful execution hooks. | |
| The return value is a flag indicating whether interpretation of | |
| commands by the interpreter should stop. | |
| """ | |
| cmd, arg, line = self.parseline(line) | |
| if not line: | |
| return self.emptyline() | |
| if cmd is None: | |
| return self.default(line) | |
| self.lastcmd = line | |
| if cmd == '': | |
| return self.default(line) | |
| else: | |
| try: | |
| func = getattr(self, 'do_' + cmd) | |
| except AttributeError: | |
| return self.default(line) | |
| return func(arg) | |
| def emptyline(self): | |
| """Called when an empty line is entered in response to the prompt. | |
| If this method is not overridden, it repeats the last nonempty | |
| command entered. | |
| """ | |
| if self.lastcmd: | |
| return self.onecmd(self.lastcmd) | |
| def default(self, line): | |
| """Called on an input line when the command prefix is not recognized. | |
| If this method is not overridden, it prints an error message and | |
| returns. | |
| """ | |
| self.stdout.write('*** Unknown syntax: %s\n'%line) | |
| def completedefault(self, *ignored): | |
| """Method called to complete an input line when no command-specific | |
| complete_*() method is available. | |
| By default, it returns an empty list. | |
| """ | |
| return [] | |
| def completenames(self, text, *ignored): | |
| dotext = 'do_'+text | |
| return [a[3:] for a in self.get_names() if a.startswith(dotext)] | |
| def complete(self, text, state): | |
| """Return the next possible completion for 'text'. | |
| If a command has not been entered, then complete against command list. | |
| Otherwise try to call complete_<command> to get list of completions. | |
| """ | |
| if state == 0: | |
| import readline | |
| origline = readline.get_line_buffer() | |
| line = origline.lstrip() | |
| stripped = len(origline) - len(line) | |
| begidx = readline.get_begidx() - stripped | |
| endidx = readline.get_endidx() - stripped | |
| if begidx>0: | |
| cmd, args, foo = self.parseline(line) | |
| if cmd == '': | |
| compfunc = self.completedefault | |
| else: | |
| try: | |
| compfunc = getattr(self, 'complete_' + cmd) | |
| except AttributeError: | |
| compfunc = self.completedefault | |
| else: | |
| compfunc = self.completenames | |
| self.completion_matches = compfunc(text, line, begidx, endidx) | |
| try: | |
| return self.completion_matches[state] | |
| except IndexError: | |
| return None | |
| def get_names(self): | |
| # This method used to pull in base class attributes | |
| # at a time dir() didn't do it yet. | |
| return dir(self.__class__) | |
| def complete_help(self, *args): | |
| commands = set(self.completenames(*args)) | |
| topics = set(a[5:] for a in self.get_names() | |
| if a.startswith('help_' + args[0])) | |
| return list(commands | topics) | |
| def do_help(self, arg): | |
| if arg: | |
| # XXX check arg syntax | |
| try: | |
| func = getattr(self, 'help_' + arg) | |
| except AttributeError: | |
| try: | |
| doc=getattr(self, 'do_' + arg).__doc__ | |
| if doc: | |
| self.stdout.write("%s\n"%str(doc)) | |
| return | |
| except AttributeError: | |
| pass | |
| self.stdout.write("%s\n"%str(self.nohelp % (arg,))) | |
| return | |
| func() | |
| else: | |
| names = self.get_names() | |
| cmds_doc = [] | |
| cmds_undoc = [] | |
| help = {} | |
| for name in names: | |
| if name[:5] == 'help_': | |
| help[name[5:]]=1 | |
| names.sort() | |
| # There can be duplicates if routines overridden | |
| prevname = '' | |
| for name in names: | |
| if name[:3] == 'do_': | |
| if name == prevname: | |
| continue | |
| prevname = name | |
| cmd=name[3:] | |
| if cmd in help: | |
| cmds_doc.append(cmd) | |
| del help[cmd] | |
| elif getattr(self, name).__doc__: | |
| cmds_doc.append(cmd) | |
| else: | |
| cmds_undoc.append(cmd) | |
| self.stdout.write("%s\n"%str(self.doc_leader)) | |
| self.print_topics(self.doc_header, cmds_doc, 15,80) | |
| self.print_topics(self.misc_header, help.keys(),15,80) | |
| self.print_topics(self.undoc_header, cmds_undoc, 15,80) | |
| def print_topics(self, header, cmds, cmdlen, maxcol): | |
| if cmds: | |
| self.stdout.write("%s\n"%str(header)) | |
| if self.ruler: | |
| self.stdout.write("%s\n"%str(self.ruler * len(header))) | |
| self.columnize(cmds, maxcol-1) | |
| self.stdout.write("\n") | |
| def columnize(self, list, displaywidth=80): | |
| """Display a list of strings as a compact set of columns. | |
| Each column is only as wide as necessary. | |
| Columns are separated by two spaces (one was not legible enough). | |
| """ | |
| if not list: | |
| self.stdout.write("<empty>\n") | |
| return | |
| nonstrings = [i for i in range(len(list)) | |
| if not isinstance(list[i], str)] | |
| if nonstrings: | |
| raise TypeError, ("list[i] not a string for i in %s" % | |
| ", ".join(map(str, nonstrings))) | |
| size = len(list) | |
| if size == 1: | |
| self.stdout.write('%s\n'%str(list[0])) | |
| return | |
| # Try every row count from 1 upwards | |
| for nrows in range(1, len(list)): | |
| ncols = (size+nrows-1) // nrows | |
| colwidths = [] | |
| totwidth = -2 | |
| for col in range(ncols): | |
| colwidth = 0 | |
| for row in range(nrows): | |
| i = row + nrows*col | |
| if i >= size: | |
| break | |
| x = list[i] | |
| colwidth = max(colwidth, len(x)) | |
| colwidths.append(colwidth) | |
| totwidth += colwidth + 2 | |
| if totwidth > displaywidth: | |
| break | |
| if totwidth <= displaywidth: | |
| break | |
| else: | |
| nrows = len(list) | |
| ncols = 1 | |
| colwidths = [0] | |
| for row in range(nrows): | |
| texts = [] | |
| for col in range(ncols): | |
| i = row + nrows*col | |
| if i >= size: | |
| x = "" | |
| else: | |
| x = list[i] | |
| texts.append(x) | |
| while texts and not texts[-1]: | |
| del texts[-1] | |
| for col in range(len(texts)): | |
| texts[col] = texts[col].ljust(colwidths[col]) | |
| self.stdout.write("%s\n"%str(" ".join(texts))) |