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- # 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.
- #
- # The `default' method may be overridden to intercept commands for which there
- # is no do_ 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
- import sys
- import linecache
-
- PROMPT = '(Cmd) '
- IDENTCHARS = string.letters + string.digits + '_'
-
- class Cmd:
- prompt = PROMPT
- identchars = IDENTCHARS
- ruler = '='
- lastcmd = ''
- cmdqueue = []
- 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"
-
- def __init__(self): pass
-
- def cmdloop(self, intro=None):
- self.preloop()
- if intro != None:
- self.intro = intro
- if self.intro:
- print self.intro
- stop = None
- while not stop:
- if self.cmdqueue:
- line = self.cmdqueue[0]
- del self.cmdqueue[0]
- else:
- try:
- line = raw_input(self.prompt)
- except EOFError:
- line = 'EOF'
- line = self.precmd(line)
- stop = self.onecmd(line)
- stop = self.postcmd(stop, line)
- self.postloop()
-
- def precmd(self, line):
- return line
-
- def postcmd(self, stop, line):
- return stop
-
- def preloop(self):
- pass
-
- def postloop(self):
- pass
-
- def onecmd(self, line):
- line = string.strip(line)
- if line == '?':
- line = 'help'
- elif line == '!':
- if hasattr(self, 'do_shell'):
- line = 'shell'
- else:
- return self.default(line)
- elif not line:
- return self.emptyline()
- self.lastcmd = line
- i, n = 0, len(line)
- while i < n and line[i] in self.identchars: i = i+1
- cmd, arg = line[:i], string.strip(line[i:])
- 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):
- if self.lastcmd:
- return self.onecmd(self.lastcmd)
-
- def default(self, line):
- print '*** Unknown syntax:', line
-
- def do_help(self, arg):
- if arg:
- # XXX check arg syntax
- try:
- func = getattr(self, 'help_' + arg)
- except:
- try:
- doc=getattr(self, 'do_' + arg).__doc__
- if doc:
- print doc
- return
- except:
- pass
- print self.nohelp % (arg,)
- return
- func()
- else:
- # Inheritance says we have to look in class and
- # base classes; order is not important.
- names = []
- classes = [self.__class__]
- while classes:
- aclass = classes[0]
- if aclass.__bases__:
- classes = classes + list(aclass.__bases__)
- names = names + dir(aclass)
- del classes[0]
- 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 help.has_key(cmd):
- cmds_doc.append(cmd)
- del help[cmd]
- elif getattr(self, name).__doc__:
- cmds_doc.append(cmd)
- else:
- cmds_undoc.append(cmd)
- print 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:
- print header;
- if self.ruler:
- print self.ruler * len(header)
- (cmds_per_line,junk)=divmod(maxcol,cmdlen)
- col=cmds_per_line
- for cmd in cmds:
- if col==0: print
- print (("%-"+`cmdlen`+"s") % cmd),
- col = (col+1) % cmds_per_line
- print "\n"
-