1 # Copyright 2010-2012 Avery Pennarun and options.py contributors.
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32 """Command-line options parser.
33 With the help of an options spec string, easily parse command-line options.
35 An options spec is made up of two parts, separated by a line with two dashes.
36 The first part is the synopsis of the command and the second one specifies
37 options, one per line.
39 Each non-empty line in the synopsis gives a set of options that can be used
42 Option flags must be at the begining of the line and multiple flags are
43 separated by commas. Usually, options have a short, one character flag, and a
44 longer one, but the short one can be omitted.
46 Long option flags are used as the option's key for the OptDict produced when
49 When the flag definition is ended with an equal sign, the option takes
50 one string as an argument, and that string will be converted to an
51 integer when possible. Otherwise, the option does not take an argument
52 and corresponds to a boolean flag that is true when the option is
53 given on the command line.
55 The option's description is found at the right of its flags definition, after
56 one or more spaces. The description ends at the end of the line. If the
57 description contains text enclosed in square brackets, the enclosed text will
58 be used as the option's default value.
60 Options can be put in different groups. Options in the same group must be on
61 consecutive lines. Groups are formed by inserting a line that begins with a
62 space. The text on that line will be output after an empty line.
65 from __future__ import absolute_import
66 import sys, os, textwrap, getopt, re, struct
79 def _invert(v, invert):
85 def _remove_negative_kv(k, v):
86 if k.startswith('no-') or k.startswith('no_'):
91 class OptDict(object):
92 """Dictionary that exposes keys as attributes.
94 Keys can be set or accessed with a "no-" or "no_" prefix to negate the
97 def __init__(self, aliases):
99 self._aliases = aliases
101 def _unalias(self, k):
102 k, reinvert = _remove_negative_kv(k, False)
103 k, invert = self._aliases[k]
104 return k, invert ^ reinvert
106 def __setitem__(self, k, v):
107 k, invert = self._unalias(k)
108 self._opts[k] = _invert(v, invert)
110 def __getitem__(self, k):
111 k, invert = self._unalias(k)
112 return _invert(self._opts[k], invert)
114 def __getattr__(self, k):
118 def _default_onabort(msg):
139 if not fcntl and termios:
144 s = struct.pack("HHHH", 0, 0, 0, 0)
146 s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
149 ysize, xsize, ypix, xpix = struct.unpack('HHHH', s)
155 When constructed, a string called an option spec must be given. It
156 specifies the synopsis and option flags and their description. For more
157 information about option specs, see the docstring at the top of this file.
159 Two optional arguments specify an alternative parsing function and an
160 alternative behaviour on abort (after having output the usage string).
162 By default, the parser function is getopt.gnu_getopt, and the abort
163 behaviour is to exit the program.
165 def __init__(self, optspec, optfunc=getopt.gnu_getopt,
166 onabort=_default_onabort):
167 self.optspec = optspec
168 self._onabort = onabort
169 self.optfunc = optfunc
171 self._shortopts = 'h?'
172 self._longopts = ['help', 'usage']
175 self._usagestr = self._gen_usage() # this also parses the optspec
177 def _gen_usage(self):
179 lines = self.optspec.strip().split('\n')
185 out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
188 last_was_option = False
191 if l.startswith(' '):
192 out.append('%s%s\n' % (last_was_option and '\n' or '',
194 last_was_option = False
196 (flags,extra) = (l + ' ').split(' ', 1)
197 extra = extra.strip()
198 if flags.endswith('='):
203 g = re.search(r'\[([^\]]*)\]$', extra)
205 defval = _intify(g.group(1))
208 flagl = flags.split(',')
210 flag_main, invert_main = _remove_negative_kv(flagl[0], False)
211 self._defaults[flag_main] = _invert(defval, invert_main)
213 f,invert = _remove_negative_kv(_f, 0)
214 self._aliases[f] = (flag_main, invert_main ^ invert)
215 self._hasparms[f] = has_parm
217 self._shortopts += '0123456789'
218 flagl_nice.append('-#')
220 self._shortopts += f + (has_parm and ':' or '')
221 flagl_nice.append('-' + f)
223 f_nice = re.sub(r'\W', '_', f)
224 self._aliases[f_nice] = (flag_main,
225 invert_main ^ invert)
226 self._longopts.append(f + (has_parm and '=' or ''))
227 self._longopts.append('no-' + f)
228 flagl_nice.append('--' + _f)
229 flags_nice = ', '.join(flagl_nice)
232 prefix = ' %-20s ' % flags_nice
233 argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
234 initial_indent=prefix,
235 subsequent_indent=' '*28))
236 out.append(argtext + '\n')
237 last_was_option = True
240 last_was_option = False
241 return ''.join(out).rstrip() + '\n'
243 def usage(self, msg=""):
244 """Print usage string to stderr and abort."""
245 sys.stderr.write(self._usagestr)
247 sys.stderr.write(msg)
248 e = self._onabort and self._onabort(msg) or None
252 def fatal(self, msg):
253 """Print an error message to stderr and abort with usage string."""
254 msg = '\nerror: %s\n' % msg
255 return self.usage(msg)
257 def parse(self, args):
258 """Parse a list of arguments and return (options, flags, extra).
260 In the returned tuple, "options" is an OptDict with known options,
261 "flags" is a list of option flags that were used on the command-line,
262 and "extra" is a list of positional arguments.
265 (flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
266 except getopt.GetoptError as e:
269 opt = OptDict(aliases=self._aliases)
271 for k,v in self._defaults.items():
276 if k in ('h', '?', 'help', 'usage'):
278 if (self._aliases.get('#') and
279 k in ('0','1','2','3','4','5','6','7','8','9')):
280 v = int(k) # guaranteed to be exactly one digit
281 k, invert = self._aliases['#']
284 k, invert = opt._unalias(k)
285 if not self._hasparms[k]:
287 v = (opt._opts.get(k) or 0) + 1
290 opt[k] = _invert(v, invert)
291 return (opt,flags,extra)