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):
132 if not fcntl and termios:
137 s = struct.pack("HHHH", 0, 0, 0, 0)
139 s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
142 ysize, xsize, ypix, xpix = struct.unpack('HHHH', s)
148 When constructed, a string called an option spec must be given. It
149 specifies the synopsis and option flags and their description. For more
150 information about option specs, see the docstring at the top of this file.
152 Two optional arguments specify an alternative parsing function and an
153 alternative behaviour on abort (after having output the usage string).
155 By default, the parser function is getopt.gnu_getopt, and the abort
156 behaviour is to exit the program.
158 def __init__(self, optspec, optfunc=getopt.gnu_getopt,
159 onabort=_default_onabort):
160 self.optspec = optspec
161 self._onabort = onabort
162 self.optfunc = optfunc
164 self._shortopts = 'h?'
165 self._longopts = ['help', 'usage']
168 self._usagestr = self._gen_usage() # this also parses the optspec
170 def _gen_usage(self):
172 lines = self.optspec.strip().split('\n')
178 out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
181 last_was_option = False
184 if l.startswith(' '):
185 out.append('%s%s\n' % (last_was_option and '\n' or '',
187 last_was_option = False
189 (flags,extra) = (l + ' ').split(' ', 1)
190 extra = extra.strip()
191 if flags.endswith('='):
196 g = re.search(r'\[([^\]]*)\]$', extra)
198 defval = _intify(g.group(1))
201 flagl = flags.split(',')
203 flag_main, invert_main = _remove_negative_kv(flagl[0], False)
204 self._defaults[flag_main] = _invert(defval, invert_main)
206 f,invert = _remove_negative_kv(_f, 0)
207 self._aliases[f] = (flag_main, invert_main ^ invert)
208 self._hasparms[f] = has_parm
210 self._shortopts += '0123456789'
211 flagl_nice.append('-#')
213 self._shortopts += f + (has_parm and ':' or '')
214 flagl_nice.append('-' + f)
216 f_nice = re.sub(r'\W', '_', f)
217 self._aliases[f_nice] = (flag_main,
218 invert_main ^ invert)
219 self._longopts.append(f + (has_parm and '=' or ''))
220 self._longopts.append('no-' + f)
221 flagl_nice.append('--' + _f)
222 flags_nice = ', '.join(flagl_nice)
225 prefix = ' %-20s ' % flags_nice
226 argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
227 initial_indent=prefix,
228 subsequent_indent=' '*28))
229 out.append(argtext + '\n')
230 last_was_option = True
233 last_was_option = False
234 return ''.join(out).rstrip() + '\n'
236 def usage(self, msg=""):
237 """Print usage string to stderr and abort."""
238 sys.stderr.write(self._usagestr)
240 sys.stderr.write(msg)
241 e = self._onabort and self._onabort(msg) or None
245 def fatal(self, msg):
246 """Print an error message to stderr and abort with usage string."""
247 msg = '\nerror: %s\n' % msg
248 return self.usage(msg)
250 def parse(self, args):
251 """Parse a list of arguments and return (options, flags, extra).
253 In the returned tuple, "options" is an OptDict with known options,
254 "flags" is a list of option flags that were used on the command-line,
255 and "extra" is a list of positional arguments.
258 (flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
259 except getopt.GetoptError as e:
262 opt = OptDict(aliases=self._aliases)
264 for k,v in self._defaults.items():
269 if k in ('h', '?', 'help', 'usage'):
271 if (self._aliases.get('#') and
272 k in ('0','1','2','3','4','5','6','7','8','9')):
273 v = int(k) # guaranteed to be exactly one digit
274 k, invert = self._aliases['#']
277 k, invert = opt._unalias(k)
278 if not self._hasparms[k]:
280 v = (opt._opts.get(k) or 0) + 1
283 opt[k] = _invert(v, invert)
284 return (opt,flags,extra)