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 one
49 string as an argument. Otherwise, the option does not take an argument and
50 corresponds to a boolean flag that is true when the option is given on the
53 The option's description is found at the right of its flags definition, after
54 one or more spaces. The description ends at the end of the line. If the
55 description contains text enclosed in square brackets, the enclosed text will
56 be used as the option's default value.
58 Options can be put in different groups. Options in the same group must be on
59 consecutive lines. Groups are formed by inserting a line that begins with a
60 space. The text on that line will be output after an empty line.
62 import sys, os, textwrap, getopt, re, struct
65 def _invert(v, invert):
71 def _remove_negative_kv(k, v):
72 if k.startswith('no-') or k.startswith('no_'):
77 class OptDict(object):
78 """Dictionary that exposes keys as attributes.
80 Keys can be set or accessed with a "no-" or "no_" prefix to negate the
83 def __init__(self, aliases):
85 self._aliases = aliases
87 def _unalias(self, k):
88 k, reinvert = _remove_negative_kv(k, False)
89 k, invert = self._aliases[k]
90 return k, invert ^ reinvert
92 def __setitem__(self, k, v):
93 k, invert = self._unalias(k)
94 self._opts[k] = _invert(v, invert)
96 def __getitem__(self, k):
97 k, invert = self._unalias(k)
98 return _invert(self._opts[k], invert)
100 def __getattr__(self, k):
104 def _default_onabort(msg):
126 s = struct.pack("HHHH", 0, 0, 0, 0)
128 import fcntl, termios
129 s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
130 except (IOError, ImportError):
131 return _atoi(os.environ.get('WIDTH')) or 70
132 (ysize,xsize,ypix,xpix) = struct.unpack('HHHH', s)
138 When constructed, a string called an option spec must be given. It
139 specifies the synopsis and option flags and their description. For more
140 information about option specs, see the docstring at the top of this file.
142 Two optional arguments specify an alternative parsing function and an
143 alternative behaviour on abort (after having output the usage string).
145 By default, the parser function is getopt.gnu_getopt, and the abort
146 behaviour is to exit the program.
148 def __init__(self, optspec, optfunc=getopt.gnu_getopt,
149 onabort=_default_onabort):
150 self.optspec = optspec
151 self._onabort = onabort
152 self.optfunc = optfunc
154 self._shortopts = 'h?'
155 self._longopts = ['help', 'usage']
158 self._usagestr = self._gen_usage() # this also parses the optspec
160 def _gen_usage(self):
162 lines = self.optspec.strip().split('\n')
168 out.append('%s: %s\n' % (first_syn and 'usage' or ' or', l))
171 last_was_option = False
174 if l.startswith(' '):
175 out.append('%s%s\n' % (last_was_option and '\n' or '',
177 last_was_option = False
179 (flags,extra) = (l + ' ').split(' ', 1)
180 extra = extra.strip()
181 if flags.endswith('='):
186 g = re.search(r'\[([^\]]*)\]$', extra)
188 defval = _intify(g.group(1))
191 flagl = flags.split(',')
193 flag_main, invert_main = _remove_negative_kv(flagl[0], False)
194 self._defaults[flag_main] = _invert(defval, invert_main)
196 f,invert = _remove_negative_kv(_f, 0)
197 self._aliases[f] = (flag_main, invert_main ^ invert)
198 self._hasparms[f] = has_parm
200 self._shortopts += '0123456789'
201 flagl_nice.append('-#')
203 self._shortopts += f + (has_parm and ':' or '')
204 flagl_nice.append('-' + f)
206 f_nice = re.sub(r'\W', '_', f)
207 self._aliases[f_nice] = (flag_main,
208 invert_main ^ invert)
209 self._longopts.append(f + (has_parm and '=' or ''))
210 self._longopts.append('no-' + f)
211 flagl_nice.append('--' + _f)
212 flags_nice = ', '.join(flagl_nice)
215 prefix = ' %-20s ' % flags_nice
216 argtext = '\n'.join(textwrap.wrap(extra, width=_tty_width(),
217 initial_indent=prefix,
218 subsequent_indent=' '*28))
219 out.append(argtext + '\n')
220 last_was_option = True
223 last_was_option = False
224 return ''.join(out).rstrip() + '\n'
226 def usage(self, msg=""):
227 """Print usage string to stderr and abort."""
228 sys.stderr.write(self._usagestr)
230 sys.stderr.write(msg)
231 e = self._onabort and self._onabort(msg) or None
235 def fatal(self, msg):
236 """Print an error message to stderr and abort with usage string."""
237 msg = '\nerror: %s\n' % msg
238 return self.usage(msg)
240 def parse(self, args):
241 """Parse a list of arguments and return (options, flags, extra).
243 In the returned tuple, "options" is an OptDict with known options,
244 "flags" is a list of option flags that were used on the command-line,
245 and "extra" is a list of positional arguments.
248 (flags,extra) = self.optfunc(args, self._shortopts, self._longopts)
249 except getopt.GetoptError, e:
252 opt = OptDict(aliases=self._aliases)
254 for k,v in self._defaults.iteritems():
259 if k in ('h', '?', 'help', 'usage'):
261 if (self._aliases.get('#') and
262 k in ('0','1','2','3','4','5','6','7','8','9')):
263 v = int(k) # guaranteed to be exactly one digit
264 k, invert = self._aliases['#']
267 k, invert = opt._unalias(k)
268 if not self._hasparms[k]:
270 v = (opt._opts.get(k) or 0) + 1
273 opt[k] = _invert(v, invert)
274 return (opt,flags,extra)