1 """A generic class to build line-oriented command interpreters.
3 Interpreters constructed with this class obey the following conventions:
5 1. End of file on input is processed as the command 'EOF'.
6 2. A command is parsed out of each line by collecting the prefix composed
7 of characters in the identchars member.
8 3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method
9 is passed a single argument consisting of the remainder of the line.
10 4. Typing an empty line repeats the last command. (Actually, it calls the
11 method `emptyline', which may be overridden in a subclass.)
12 5. There is a predefined `help' method. Given an argument `topic', it
13 calls the command `help_topic'. With no arguments, it lists all topics
14 with defined help_ functions, broken into up to three topics; documented
15 commands, miscellaneous help topics, and undocumented commands.
16 6. The command '?' is a synonym for `help'. The command '!' is a synonym
17 for `shell', if a do_shell method exists.
18 7. If completion is enabled, completing commands will be done automatically,
19 and completing of commands args is done by calling complete_foo() with
20 arguments text, line, begidx, endidx. text is string we are matching
21 against, all returned matches must begin with it. line is the current
22 input line (lstripped), begidx and endidx are the beginning and end
23 indexes of the text being matched, which could be used to provide
24 different completion depending upon which position the argument is in.
26 The `default' method may be overridden to intercept commands for which there
29 The `completedefault' method may be overridden to intercept completions for
30 commands that have no complete_ method.
32 The data member `self.ruler' sets the character used to draw separator lines
33 in the help messages. If empty, no ruler line is drawn. It defaults to "=".
35 If the value of `self.intro' is nonempty when the cmdloop method is called,
36 it is printed out on interpreter startup. This value may be overridden
37 via an optional argument to the cmdloop() method.
39 The data members `self.doc_header', `self.misc_header', and
40 `self.undoc_header' set the headers used for the help function's
41 listings of documented functions, miscellaneous topics, and undocumented
42 functions respectively.
44 These interpreters use raw_input; thus, if the readline module is loaded,
45 they automatically support Emacs-like command history and editing features.
53 IDENTCHARS
= string
.ascii_letters
+ string
.digits
+ '_'
56 """A simple framework for writing line-oriented command interpreters.
58 These are often useful for test harnesses, administrative tools, and
59 prototypes that will later be wrapped in a more sophisticated interface.
61 A Cmd instance or subclass instance is a line-oriented interpreter
62 framework. There is no good reason to instantiate Cmd itself; rather,
63 it's useful as a superclass of an interpreter class you define yourself
64 in order to inherit Cmd's methods and encapsulate action methods.
68 identchars
= IDENTCHARS
73 doc_header
= "Documented commands (type help <topic>):"
74 misc_header
= "Miscellaneous help topics:"
75 undoc_header
= "Undocumented commands:"
76 nohelp
= "*** No help on %s"
79 def __init__(self
, completekey
='tab', stdin
=None, stdout
=None):
80 """Instantiate a line-oriented interpreter framework.
82 The optional argument 'completekey' is the readline name of a
83 completion key; it defaults to the Tab key. If completekey is
84 not None and the readline module is available, command completion
85 is done automatically. The optional arguments stdin and stdout
86 specify alternate input and output file objects; if not specified,
87 sys.stdin and sys.stdout are used.
94 self
.stdin
= sys
.stdin
95 if stdout
is not None:
98 self
.stdout
= sys
.stdout
100 self
.completekey
= completekey
102 def cmdloop(self
, intro
=None):
103 """Repeatedly issue a prompt, accept input, parse an initial prefix
104 off the received input, and dispatch to action methods, passing them
105 the remainder of the line as argument.
110 if self
.use_rawinput
and self
.completekey
:
113 self
.old_completer
= readline
.get_completer()
114 readline
.set_completer(self
.complete
)
115 readline
.parse_and_bind(self
.completekey
+": complete")
119 if intro
is not None:
122 self
.stdout
.write(str(self
.intro
)+"\n")
126 line
= self
.cmdqueue
.pop(0)
128 if self
.use_rawinput
:
130 line
= raw_input(self
.prompt
)
134 self
.stdout
.write(self
.prompt
)
136 line
= self
.stdin
.readline()
140 line
= line
[:-1] # chop \n
141 line
= self
.precmd(line
)
142 stop
= self
.onecmd(line
)
143 stop
= self
.postcmd(stop
, line
)
146 if self
.use_rawinput
and self
.completekey
:
149 readline
.set_completer(self
.old_completer
)
154 def precmd(self
, line
):
155 """Hook method executed just before the command line is
156 interpreted, but after the input prompt is generated and issued.
161 def postcmd(self
, stop
, line
):
162 """Hook method executed just after a command dispatch is finished."""
166 """Hook method executed once when the cmdloop() method is called."""
170 """Hook method executed once when the cmdloop() method is about to
176 def parseline(self
, line
):
177 """Parse the line into a command name and a string containing
178 the arguments. Returns a tuple containing (command, args, line).
179 'command' and 'args' may be None if the line couldn't be parsed.
183 return None, None, line
185 line
= 'help ' + line
[1:]
187 if hasattr(self
, 'do_shell'):
188 line
= 'shell ' + line
[1:]
190 return None, None, line
192 while i
< n
and line
[i
] in self
.identchars
: i
= i
+1
193 cmd
, arg
= line
[:i
], line
[i
:].strip()
194 return cmd
, arg
, line
196 def onecmd(self
, line
):
197 """Interpret the argument as though it had been typed in response
200 This may be overridden, but should not normally need to be;
201 see the precmd() and postcmd() methods for useful execution hooks.
202 The return value is a flag indicating whether interpretation of
203 commands by the interpreter should stop.
206 cmd
, arg
, line
= self
.parseline(line
)
208 return self
.emptyline()
210 return self
.default(line
)
213 return self
.default(line
)
216 func
= getattr(self
, 'do_' + cmd
)
217 except AttributeError:
218 return self
.default(line
)
222 """Called when an empty line is entered in response to the prompt.
224 If this method is not overridden, it repeats the last nonempty
229 return self
.onecmd(self
.lastcmd
)
231 def default(self
, line
):
232 """Called on an input line when the command prefix is not recognized.
234 If this method is not overridden, it prints an error message and
238 self
.stdout
.write('*** Unknown syntax: %s\n'%line
)
240 def completedefault(self
, *ignored
):
241 """Method called to complete an input line when no command-specific
242 complete_*() method is available.
244 By default, it returns an empty list.
249 def completenames(self
, text
, *ignored
):
251 return [a
[3:] for a
in self
.get_names() if a
.startswith(dotext
)]
253 def complete(self
, text
, state
):
254 """Return the next possible completion for 'text'.
256 If a command has not been entered, then complete against command list.
257 Otherwise try to call complete_<command> to get list of completions.
261 origline
= readline
.get_line_buffer()
262 line
= origline
.lstrip()
263 stripped
= len(origline
) - len(line
)
264 begidx
= readline
.get_begidx() - stripped
265 endidx
= readline
.get_endidx() - stripped
267 cmd
, args
, foo
= self
.parseline(line
)
269 compfunc
= self
.completedefault
272 compfunc
= getattr(self
, 'complete_' + cmd
)
273 except AttributeError:
274 compfunc
= self
.completedefault
276 compfunc
= self
.completenames
277 self
.completion_matches
= compfunc(text
, line
, begidx
, endidx
)
279 return self
.completion_matches
[state
]
284 # This method used to pull in base class attributes
285 # at a time dir() didn't do it yet.
286 return dir(self
.__class
__)
288 def complete_help(self
, *args
):
289 commands
= set(self
.completenames(*args
))
290 topics
= set(a
[5:] for a
in self
.get_names()
291 if a
.startswith('help_' + args
[0]))
292 return list(commands | topics
)
294 def do_help(self
, arg
):
296 # XXX check arg syntax
298 func
= getattr(self
, 'help_' + arg
)
299 except AttributeError:
301 doc
=getattr(self
, 'do_' + arg
).__doc
__
303 self
.stdout
.write("%s\n"%str
(doc
))
305 except AttributeError:
307 self
.stdout
.write("%s\n"%str
(self
.nohelp
% (arg
,)))
311 names
= self
.get_names()
316 if name
[:5] == 'help_':
319 # There can be duplicates if routines overridden
322 if name
[:3] == 'do_':
330 elif getattr(self
, name
).__doc
__:
333 cmds_undoc
.append(cmd
)
334 self
.stdout
.write("%s\n"%str
(self
.doc_leader
))
335 self
.print_topics(self
.doc_header
, cmds_doc
, 15,80)
336 self
.print_topics(self
.misc_header
, help.keys(),15,80)
337 self
.print_topics(self
.undoc_header
, cmds_undoc
, 15,80)
339 def print_topics(self
, header
, cmds
, cmdlen
, maxcol
):
341 self
.stdout
.write("%s\n"%str
(header
))
343 self
.stdout
.write("%s\n"%str
(self
.ruler
* len(header
)))
344 self
.columnize(cmds
, maxcol
-1)
345 self
.stdout
.write("\n")
347 def columnize(self
, list, displaywidth
=80):
348 """Display a list of strings as a compact set of columns.
350 Each column is only as wide as necessary.
351 Columns are separated by two spaces (one was not legible enough).
354 self
.stdout
.write("<empty>\n")
356 nonstrings
= [i
for i
in range(len(list))
357 if not isinstance(list[i
], str)]
359 raise TypeError, ("list[i] not a string for i in %s" %
360 ", ".join(map(str, nonstrings
)))
363 self
.stdout
.write('%s\n'%str
(list[0]))
365 # Try every row count from 1 upwards
366 for nrows
in range(1, len(list)):
367 ncols
= (size
+nrows
-1) // nrows
370 for col
in range(ncols
):
372 for row
in range(nrows
):
377 colwidth
= max(colwidth
, len(x
))
378 colwidths
.append(colwidth
)
379 totwidth
+= colwidth
+ 2
380 if totwidth
> displaywidth
:
382 if totwidth
<= displaywidth
:
388 for row
in range(nrows
):
390 for col
in range(ncols
):
397 while texts
and not texts
[-1]:
399 for col
in range(len(texts
)):
400 texts
[col
] = texts
[col
].ljust(colwidths
[col
])
401 self
.stdout
.write("%s\n"%str
(" ".join(texts
)))