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
66 def _invert(v, invert):
72 def _remove_negative_kv(k, v):
73 if k.startswith('no-') or k.startswith('no_'):
78 class OptDict(object):
79 """Dictionary that exposes keys as attributes.
81 Keys can be set or accessed with a "no-" or "no_" prefix to negate the
84 def __init__(self, aliases):
86 self._aliases = aliases
88 def _unalias(self, k):
89 k, reinvert = _remove_negative_kv(k, False)
90 k, invert = self._aliases[k]
91 return k, invert ^ reinvert
93 def __setitem__(self, k, v):
94 k, invert = self._unalias(k)
95 self._opts[k] = _invert(v, invert)
97 def __getitem__(self, k):
98 k, invert = self._unalias(k)
99 return _invert(self._opts[k], invert)
101 def __getattr__(self, k):
105 def _default_onabort(msg):
127 s = struct.pack("HHHH", 0, 0, 0, 0)
129 import fcntl, termios
130 s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
131 except (IOError, ImportError):
132 return _atoi(os.environ.get('WIDTH')) or 70
133 (ysize,xsize,ypix,xpix) = struct.unpack('HHHH', s)
139 When constructed, a string called an option spec must be given. It
140 specifies the synopsis and option flags and their description. For more
141 information about option specs, see the docstring at the top of this file.
143 Two optional arguments specify an alternative parsing function and an
144 alternative behaviour on abort (after having output the usage string).
146 By default, the parser function is getopt.gnu_getopt, and the abort
147 behaviour is to exit the program.
149 def __init__(self, optspec, optfunc=getopt.gnu_getopt,
150 onabort=_default_onabort):
151 self.optspec = optspec
152 self._onabort = onabort
153 self.optfunc = optfunc
155 self._shortopts = 'h?'
156 self._longopts = ['help', 'usage']
159 self._usagestr = self._gen_usage() # this also parses the optspec
161 def _gen_usage(self):
163 lines = self.optspec.strip().split('\n')
169 out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
172 last_was_option = False
175 if l.startswith(' '):
176 out.append('%s%s\n' % (last_was_option and '\n' or '',
178 last_was_option = False
180 (flags,extra) = (l + ' ').split(' ', 1)
181 extra = extra.strip()
182 if flags.endswith('='):
187 g = re.search(r'\[([^\]]*)\]$', extra)
189 defval = _intify(g.group(1))
192 flagl = flags.split(',')
194 flag_main, invert_main = _remove_negative_kv(flagl[0], False)
195 self._defaults[flag_main] = _invert(defval, invert_main)
197 f,invert = _remove_negative_kv(_f, 0)
198 self._aliases[f] = (flag_main, invert_main ^ invert)
199 self._hasparms[f] = has_parm
201 self._shortopts += '0123456789'
202 flagl_nice.append('-#')
204 self._shortopts += f + (has_parm and ':' or '')
205 flagl_nice.append('-' + f)
207 f_nice = re.sub(r'\W', '_', f)
208 self._aliases[f_nice] = (flag_main,
209 invert_main ^ invert)
210 self._longopts.append(f + (has_parm and '=' or ''))
211 self._longopts.append('no-' + f)
212 flagl_nice.append('--' + _f)
213 flags_nice = ', '.join(flagl_nice)
216 prefix = ' %-20s ' % flags_nice
217 argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
218 initial_indent=prefix,
219 subsequent_indent=' '*28))
220 out.append(argtext + '\n')
221 last_was_option = True
224 last_was_option = False
225 return ''.join(out).rstrip() + '\n'
227 def usage(self, msg=""):
228 """Print usage string to stderr and abort."""
229 sys.stderr.write(self._usagestr)
231 sys.stderr.write(msg)
232 e = self._onabort and self._onabort(msg) or None
236 def fatal(self, msg):
237 """Print an error message to stderr and abort with usage string."""
238 msg = '\nerror: %s\n' % msg
239 return self.usage(msg)
241 def parse(self, args):
242 """Parse a list of arguments and return (options, flags, extra).
244 In the returned tuple, "options" is an OptDict with known options,
245 "flags" is a list of option flags that were used on the command-line,
246 and "extra" is a list of positional arguments.
249 (flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
250 except getopt.GetoptError, e:
253 opt = OptDict(aliases=self._aliases)
255 for k,v in self._defaults.iteritems():
260 if k in ('h', '?', 'help', 'usage'):
262 if (self._aliases.get('#') and
263 k in ('0','1','2','3','4','5','6','7','8','9')):
264 v = int(k) # guaranteed to be exactly one digit
265 k, invert = self._aliases['#']
268 k, invert = opt._unalias(k)
269 if not self._hasparms[k]:
271 v = (opt._opts.get(k) or 0) + 1
274 opt[k] = _invert(v, invert)
275 return (opt,flags,extra)