1 # Copyright 2010-2012 Avery Pennarun and options.py contributors.
4 # (This license applies to this file but not necessarily the other files in
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8 # modification, are permitted provided that the following conditions are
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31 """Command-line options parser.
32 With the help of an options spec string, easily parse command-line options.
34 An options spec is made up of two parts, separated by a line with two dashes.
35 The first part is the synopsis of the command and the second one specifies
36 options, one per line.
38 Each non-empty line in the synopsis gives a set of options that can be used
41 Option flags must be at the begining of the line and multiple flags are
42 separated by commas. Usually, options have a short, one character flag, and a
43 longer one, but the short one can be omitted.
45 Long option flags are used as the option's key for the OptDict produced when
48 When the flag definition is ended with an equal sign, the option takes
49 one string as an argument, and that string will be converted to an
50 integer when possible. Otherwise, the option does not take an argument
51 and corresponds to a boolean flag that is true when the option is
52 given on the command line.
54 The option's description is found at the right of its flags definition, after
55 one or more spaces. The description ends at the end of the line. If the
56 description contains text enclosed in square brackets, the enclosed text will
57 be used as the option's default value.
59 Options can be put in different groups. Options in the same group must be on
60 consecutive lines. Groups are formed by inserting a line that begins with a
61 space. The text on that line will be output after an empty line.
63 import sys, os, textwrap, getopt, re, struct
76 def _invert(v, invert):
82 def _remove_negative_kv(k, v):
83 if k.startswith('no-') or k.startswith('no_'):
88 class OptDict(object):
89 """Dictionary that exposes keys as attributes.
91 Keys can be set or accessed with a "no-" or "no_" prefix to negate the
94 def __init__(self, aliases):
96 self._aliases = aliases
98 def _unalias(self, k):
99 k, reinvert = _remove_negative_kv(k, False)
100 k, invert = self._aliases[k]
101 return k, invert ^ reinvert
103 def __setitem__(self, k, v):
104 k, invert = self._unalias(k)
105 self._opts[k] = _invert(v, invert)
107 def __getitem__(self, k):
108 k, invert = self._unalias(k)
109 return _invert(self._opts[k], invert)
111 def __getattr__(self, k):
115 def _default_onabort(msg):
136 if not fcntl and termios:
141 s = struct.pack("HHHH", 0, 0, 0, 0)
143 s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
146 ysize, xsize, ypix, xpix = struct.unpack('HHHH', s)
152 When constructed, a string called an option spec must be given. It
153 specifies the synopsis and option flags and their description. For more
154 information about option specs, see the docstring at the top of this file.
156 Two optional arguments specify an alternative parsing function and an
157 alternative behaviour on abort (after having output the usage string).
159 By default, the parser function is getopt.gnu_getopt, and the abort
160 behaviour is to exit the program.
162 def __init__(self, optspec, optfunc=getopt.gnu_getopt,
163 onabort=_default_onabort):
164 self.optspec = optspec
165 self._onabort = onabort
166 self.optfunc = optfunc
168 self._shortopts = 'h?'
169 self._longopts = ['help', 'usage']
172 self._usagestr = self._gen_usage() # this also parses the optspec
174 def _gen_usage(self):
176 lines = self.optspec.strip().split('\n')
182 out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
185 last_was_option = False
188 if l.startswith(' '):
189 out.append('%s%s\n' % (last_was_option and '\n' or '',
191 last_was_option = False
193 (flags,extra) = (l + ' ').split(' ', 1)
194 extra = extra.strip()
195 if flags.endswith('='):
200 g = re.search(r'\[([^\]]*)\]$', extra)
202 defval = _intify(g.group(1))
205 flagl = flags.split(',')
207 flag_main, invert_main = _remove_negative_kv(flagl[0], False)
208 self._defaults[flag_main] = _invert(defval, invert_main)
210 f,invert = _remove_negative_kv(_f, 0)
211 self._aliases[f] = (flag_main, invert_main ^ invert)
212 self._hasparms[f] = has_parm
214 self._shortopts += '0123456789'
215 flagl_nice.append('-#')
217 self._shortopts += f + (has_parm and ':' or '')
218 flagl_nice.append('-' + f)
220 f_nice = re.sub(r'\W', '_', f)
221 self._aliases[f_nice] = (flag_main,
222 invert_main ^ invert)
223 self._longopts.append(f + (has_parm and '=' or ''))
224 self._longopts.append('no-' + f)
225 flagl_nice.append('--' + _f)
226 flags_nice = ', '.join(flagl_nice)
229 prefix = ' %-20s ' % flags_nice
230 argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
231 initial_indent=prefix,
232 subsequent_indent=' '*28))
233 out.append(argtext + '\n')
234 last_was_option = True
237 last_was_option = False
238 return ''.join(out).rstrip() + '\n'
240 def usage(self, msg=""):
241 """Print usage string to stderr and abort."""
242 sys.stderr.write(self._usagestr)
244 sys.stderr.write(msg)
245 e = self._onabort and self._onabort(msg) or None
249 def fatal(self, msg):
250 """Print an error message to stderr and abort with usage string."""
251 msg = '\nerror: %s\n' % msg
252 return self.usage(msg)
254 def parse(self, args):
255 """Parse a list of arguments and return (options, flags, extra).
257 In the returned tuple, "options" is an OptDict with known options,
258 "flags" is a list of option flags that were used on the command-line,
259 and "extra" is a list of positional arguments.
262 (flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
263 except getopt.GetoptError as e:
266 opt = OptDict(aliases=self._aliases)
268 for k,v in self._defaults.iteritems():
273 if k in ('h', '?', 'help', 'usage'):
275 if (self._aliases.get('#') and
276 k in ('0','1','2','3','4','5','6','7','8','9')):
277 v = int(k) # guaranteed to be exactly one digit
278 k, invert = self._aliases['#']
281 k, invert = opt._unalias(k)
282 if not self._hasparms[k]:
284 v = (opt._opts.get(k) or 0) + 1
287 opt[k] = _invert(v, invert)
288 return (opt,flags,extra)