fancyopts: allow all callable as default parameter value

The current fancyopts allows function as default parameter value
but not other callables.
By supporting other callables, we can have the benefits of e.g.,
custom __str__ method, which will be printed by 'hg help' as
the default value.

mercurial/fancyopts.py

@@ -1,123 +1,124 b''
 # fancyopts.py - better command line parsing
 #
 #  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 import getopt
 import util
 from i18n import _
 
 def gnugetopt(args, options, longoptions):
     """Parse options mostly like getopt.gnu_getopt.
 
     This is different from getopt.gnu_getopt in that an argument of - will
     become an argument of - instead of vanishing completely.
     """
     extraargs = []
     if '--' in args:
         stopindex = args.index('--')
         extraargs = args[stopindex + 1:]
         args = args[:stopindex]
     opts, parseargs = getopt.getopt(args, options, longoptions)
     args = []
     while parseargs:
         arg = parseargs.pop(0)
         if arg and arg[0] == '-' and len(arg) > 1:
             parseargs.insert(0, arg)
             topts, newparseargs = getopt.getopt(parseargs, options, longoptions)
             opts = opts + topts
             parseargs = newparseargs
         else:
             args.append(arg)
     args.extend(extraargs)
     return opts, args
 
 
 def fancyopts(args, options, state, gnu=False):
     """
     read args, parse options, and store options in state
 
     each option is a tuple of:
 
       short option or ''
       long option
       default value
       description
       option value label(optional)
 
     option types include:
 
       boolean or none - option sets variable in state to true
       string - parameter string is stored in state
       list - parameter string is added to a list
       integer - parameter strings is stored as int
       function - call function with parameter
 
     non-option args are returned
     """
     namelist = []
     shortlist = ''
     argmap = {}
     defmap = {}
 
     for option in options:
         if len(option) == 5:
             short, name, default, comment, dummy = option
         else:
             short, name, default, comment = option
         # convert opts to getopt format
         oname = name
         name = name.replace('-', '_')
 
         argmap['-' + short] = argmap['--' + oname] = name
         defmap[name] = default
 
         # copy defaults to state
         if isinstance(default, list):
             state[name] = default[:]
         elif callable(default):
             state[name] = None
         else:
             state[name] = default
 
         # does it take a parameter?
         if not (default is None or default is True or default is False):
             if short:
                 short += ':'
             if oname:
                 oname += '='
         if short:
             shortlist += short
         if name:
             namelist.append(oname)
 
     # parse arguments
     if gnu:
         parse = gnugetopt
     else:
         parse = getopt.getopt
     opts, args = parse(args, shortlist, namelist)
 
     # transfer result to state
     for opt, val in opts:
         name = argmap[opt]
-        t = type(defmap[name])
-        if t is type(fancyopts):
+        obj = defmap[name]
+        t = type(obj)
+        if callable(obj):
             state[name] = defmap[name](val)
         elif t is type(1):
             try:
                 state[name] = int(val)
             except ValueError:
                 raise util.Abort(_('invalid value %r for option %s, '
                                    'expected int') % (val, opt))
         elif t is type(''):
             state[name] = val
         elif t is type([]):
             state[name].append(val)
         elif t is type(None) or t is type(False):
             state[name] = True
 
     # return unparsed args
     return args