Source

baker / baker.py

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
#===============================================================================
# Copyright 2010 Matt Chaput
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#===============================================================================

import re, sys
from inspect import getargspec
from textwrap import wrap


def normalize_docstring(docstring):
    """Normalizes whitespace in the given string.
    """
    return re.sub(r"[\r\n\t ]+", " ", docstring).strip()


param_exp = re.compile(r"^([\t ]*):param (.*?): ([^\n]*\n(\1[ \t]+[^\n]*\n)*)",
                       re.MULTILINE)


def find_param_docs(docstring):
    """Finds ReStructuredText-style ":param:" lines in the docstring and
    returns a dictionary mapping param names to doc strings.
    """
    paramdocs = {}
    for match in param_exp.finditer(docstring):
        name = match.group(2)
        value = match.group(3)
        paramdocs[name] = value
    return paramdocs


def remove_param_docs(docstring):
    """Finds ReStructuredText-style ":param:" lines in the docstring and
    returns a new string with the param documentation removed.
    """
    return param_exp.sub("", docstring)


def process_docstring(docstring):
    """Takes a docstring and returns a list of strings representing
    the paragraphs in the docstring.
    """
    lines = docstring.split("\n")
    paras = [[]]
    for line in lines:
        if not line.strip():
            paras.append([])
        else:
            paras[-1].append(line)
    paras = [normalize_docstring(" ".join(ls))
             for ls in paras if ls]
    return paras


def format_paras(paras, width, indent=0, lstripline=[]):
    """Takes a list of paragraph strings and formats them into a word-wrapped,
    optionally indented string.
    """
    output = []
    for para in paras:
        lines = wrap(para, width - indent)
        if lines:
            for line in lines:
                output.append((" " * indent) + line)
    for i in lstripline:
        output[i] = output[i].lstrip()
    return output


def totype(v, default):
    """Tries to convert the value 'v' into the same type as 'default'.
    """
    t = type(default)
    if t is int:
        return int(v)
    elif t is float:
        return float(v)
    elif t is long:
        return long(v)
    elif t is bool:
        lv = v.lower()
        if lv in ("true", "yes", "on", "1"):
            return True
        elif lv in ("false", "no", "off", "0"):
            return False
        else:
            raise TypeError
    else:
        return v


class CommandError(Exception):
    """General exception for Baker errors, usually related to parsing the
    command line.
    """
    def __init__(self, msg, scriptname, cmd=None):
        Exception.__init__(self, msg)
        self.scriptname = scriptname
        self.commandname = cmd


class TopHelp(Exception):
    """Exception raised by Baker.parse() to indicate the user requested the
    overall help for the script, e.g. by typing "script.py help" or
    "script.py --help"
    """
    def __init__(self, scriptname):
        self.scriptname = scriptname


class CommandHelp(Exception):
    """Exception raised by baker.parse() to indicate the user requested help
    for a specific command, e.g. by typing "script.py command --help" or
    "script.py help command".
    """
    def __init__(self, scriptname, cmd):
        self.scriptname = scriptname
        self.cmd = cmd


class Cmd(object):
    """Stores metadata about a command.
    """
    def __init__(self, name, fn, argnames, keywords, shortopts,
                 has_varargs, has_kwargs, docstring, paramdocs):
        self.name = name
        self.fn = fn
        self.argnames = argnames
        self.keywords = keywords
        self.shortopts = shortopts
        self.has_varargs = has_varargs
        self.has_kwargs = has_kwargs
        self.docstring = docstring
        self.paramdocs = paramdocs


class Baker(object):
    def __init__(self):
        self.commands = {}
        self.defaultcommand = None

    def command(self, fn=None, name=None, default=False,
                params=None, shortopts=None):
        """Registers a command with the bakery. This does not call the
        function, it simply adds it to the list of functions this Baker
        knows about.

        This method is usually used as a decorator::

            b = Baker()

            @b.command
            def test():
                pass

        :param fn: the function to register.
        :param name: use this argument to register the command under a
            different name than the function name.
        :param default: if True, this command is used when a command is not
            specified on the command line.
        :param params: a dictionary mapping parameter names to docstrings. If
            you don't specify this argument, parameter annotations will be used
            (Python 3.x only), or the functions docstring will be searched for
            Sphinx-style ':param' blocks.
        :param shortopts: a dictionary mapping parameter names to short
            options, e.g. {"verbose": "v"}.
        """
        # This method works as a decorator with or without arguments.
        if fn is None:
            # The decorator was given arguments, e.g. @command(default=True),
            # so we have to return a function that will wrap the function when
            # the decorator is applied.
            return lambda fn: self.command(fn, default=default,
                                           name=name,
                                           params=params,
                                           shortopts=shortopts)
        else:
            name = name or fn.__name__

            # Inspect the argument signature of the function
            arglist, vargsname, kwargsname, keyworddefaults = getargspec(fn)
            has_varargs = bool(vargsname)
            has_kwargs = bool(kwargsname)

            # Get the function's docstring
            docstring = fn.__doc__ or ""

            # If the user didn't specify parameter help in the decorator
            # arguments, try to get it from parameter annotations (Python 3.x)
            # or RST-style :param: lines in the docstring
            if params is None:
                if hasattr(fn, "func_annotations") and fn.func_annotations:
                    # Python 3.x
                    params = fn.func_annotations
                else:
                    params = find_param_docs(docstring)
                    docstring = remove_param_docs(docstring)

            # If the user didn't specify
            shortopts = shortopts or {}

            # Zip up the keyword argument names with their defaults
            if keyworddefaults:
                keywords = dict(zip(arglist[0-len(keyworddefaults):], keyworddefaults))
            else:
                keywords = {}

            # If this is a method, remove 'self' from the argument list
            if arglist and arglist[0] == "self":
                arglist.pop(0)

            # Create a Cmd object to represent this command and store it
            cmd = Cmd(name, fn, arglist, keywords, shortopts,
                      has_varargs, has_kwargs,
                      docstring, params)
            self.commands[cmd.name] = cmd

            # If default is True, set this as the default command
            if default: self.defaultcommand = cmd

            return fn

    def usage(self, cmd=None, scriptname=None, exception=None, file=sys.stdout):
        if exception is not None:
            scriptname, cmd = exception.scriptname, exception.cmd

        if scriptname is None:
            scriptname = sys.argv[0]

        if cmd is None:
            self.print_top_help(scriptname, file=file)
        else:
            if isinstance(cmd, basestring):
                cmd = self.commands[cmd]

            self.print_command_help(scriptname, cmd, file=file)

    def openinput(self, filein):
        if filein == '-':
            return sys.stdin
        import os.path
        ext = os.path.splitext(filein)[1]
        if ext in ['.gz', '.GZ']:
            import gzip
            return gzip.open(filein, 'rb')
        if ext in ['.bz', '.bz2']:
            import bz2
            return bz2.BZ2File(filein, 'rb')
        return open(filein, 'rb')

    def writeconfig(self, iniconffile=sys.argv[0] + ".ini"):
        """OVERWRITES an ini style config file that holds all of the default command line options.

        :param iniconffile: the file name of the ini file, defaults to 'script.ini'.
        """
        import os
        fp = open(iniconffile, "w")
        for cmdname in self.commands:
            cmd = self.commands[cmdname]
            fp.write(os.linesep)
            fp.write("[{0}]".format(cmdname) + os.linesep)
            for line in self.return_cmd_doc(cmd):
                fp.write("# " + line + os.linesep)
            for line in self.return_argnames_doc(cmd):
                fp.write("# " + line + os.linesep)
            for key in cmd.keywords:
                for line in self.return_individual_keyword_doc(cmd, key, self.return_head(cmd, key)):
                    fp.write("# " + line + os.linesep)
                fp.write("{0} = {1}".format(key, cmd.keywords[key]) + os.linesep)
                fp.write(os.linesep)


    def print_top_help(self, scriptname, file=sys.stdout):
        """Prints the documentation for the script and exits.

        :param scriptname: the name of the script being executed (argv[0]).
        :param file: the file to write the help to. The default is stdout.
        """
        # Print the basic help for running a command
        file.write("\nUsage: %s COMMAND <options>\n\n" % scriptname)

        # Get a sorted list of all command names
        cmdnames = sorted(self.commands.keys())
        if cmdnames:
            # Calculate the indent for the doc strings by taking the longest
            # command name and adding 3 (one space before the name and two
            # after)
            rindent = max(len(name) for name in cmdnames) + 3

            print("Available commands:\n")
            for cmdname in cmdnames:
                # Get the Cmd object for this command
                cmd = self.commands[cmdname]

                # Calculate the padding necessary to fill from the end of the
                # command name to the documentation margin
                tab = " " * (rindent - (len(cmdname)+1))
                file.write(" " + cmdname + tab)

                # Get the paragraphs of the command's docstring
                paras = process_docstring(cmd.docstring)
                if paras:
                    # Print the first paragraph
                    file.write("\n".join(format_paras([paras[0]], 76,
                                            indent=rindent, lstripline=[0])))
                    file.write("\n")
                else:
                    file.write("\n")

        file.write("\n")
        file.write('Use "%s <command> --help" for individual command help.\n' % scriptname)

    def return_cmd_doc(self, cmd):
        # Print the documentation for this command
        paras = process_docstring(cmd.docstring)
        ret = []
        if paras:
            # Print the first paragraph with no indent (usually just a summary
            # line)
            for line in format_paras([paras[0]], 76):
                ret.append(line)

            # Print subsequent paragraphs indented by 4 spaces
            if len(paras) > 1:
                ret.append("")
                for line in format_paras(paras[1:], 76, indent=4):
                    ret.append(line)
            ret.append("")
        return ret

    def return_argnames_doc(self, cmd):
        # Added by abhikshah@gmail.com, 5/6/2010
        # Return documentation for required arguments
        ret = []
        posargs = [a for a in cmd.argnames if a not in cmd.keywords]
        if posargs:
            ret.append("")
            ret.append("Required Arguments:")
            ret.append("")

            # Find the length of the longest formatted heading
            rindent = max(len(argname) + 3 for argname in posargs)
            # Pad the headings so they're all as long as the longest one
            heads = [(head, head + (" " * (rindent - len(head))) ) for head in posargs]

            # Print the arg docs
            for keyname, head in heads:
                ret = ret + self.return_individual_keyword_doc(cmd, keyname, head, rindent=rindent)
        ret.append("")
        return ret

    def return_individual_keyword_doc(self, cmd, keyname, head, rindent=None):
        # Return documentation for optional arguments
        ret = []
        if rindent == None:
            rindent = len(head) + 2
        if keyname in cmd.paramdocs:
            paras = process_docstring(cmd.paramdocs.get(keyname, ""))
            for cnt, line in enumerate(format_paras(paras, 76, indent=rindent, lstripline=[0])):
                if cnt == 0:
                    ret.append("  " + head + line)
                else:
                    ret.append("  " + line)
        else:
            ret.append("")
        return ret

    def return_head(self, cmd, keyname):
        head = keyname
        head = " --" + head
        if keyname in cmd.shortopts:
            head = " -" + cmd.shortopts[keyname] + head
        head += "  "
        return head

    def return_keyword_doc(self, cmd):
        # Return documentation for optional arguments
        ret = []
        if cmd.keywords:
            ret.append("")
            ret.append("Options:")
            ret.append("")

            # Get a list of keyword argument names
            keynames = cmd.keywords.keys()

            # Make formatted headings, e.g. " -k --keyword  ", and put them in
            # a list like [(name, heading), ...]
            heads = []
            for keyname in keynames:
                head = self.return_head(cmd, keyname)
                heads.append((keyname, head))

            if heads:
                # Find the length of the longest formatted heading
                rindent = max(len(head) + 2 for keyname, head in heads)
                # Pad the headings so they're all as long as the longest one
                heads = [(keyname, head + (" " * (rindent - len(head) - 2)))
                         for keyname, head in heads]

                # Print the option docs
                for keyname, head in heads:
                    ret = ret + self.return_individual_keyword_doc(cmd, keyname, head, rindent)

            ret.append("")

            if any((cmd.keywords.get(a) is None) for a in cmd.argnames):
                ret.append("(specifying a double hyphen (--) in the argument list means all")
                ret.append("subsequent arguments are treated as bare arguments, not options)")
                ret.append("")
        return ret

    def print_command_help(self, scriptname, cmd, file=sys.stdout):
        """Prints the documentation for a specific command and exits.

        :param scriptname: the name of the script being executed (argv[0]).
        :param cmd: the Cmd object representing the command.
        :param file: the file to write the help to. The default is stdout.
        """

        # Print the usage for the command
        file.write("\nUsage: %s %s" % (scriptname, cmd.name))

        # Print the required and "optional" arguments (where optional
        # arguments are keyword arguments with default None).
        for name in cmd.argnames:
            if name not in cmd.keywords:
                # This is a positional argument
                file.write(" <%s>" % name)
            else:
                # This is a keyword/optional argument
                file.write(" [<%s>]" % name)

        if cmd.has_varargs:
            # This command accepts a variable number of positional arguments
            file.write(" [...]")
        file.write("\n\n")

        file.write("\n".join(self.return_cmd_doc(cmd)))

        file.write("\n".join(self.return_argnames_doc(cmd)))

        file.write("\n".join(self.return_keyword_doc(cmd)))



    def parse_args(self, scriptname, cmd, argv, test=False):
        keywords = cmd.keywords
        shortopts = cmd.shortopts

        def type_error(name, value, t):
            if not test:
                msg = "%s value %r must be %s" % (name, value, t)
                raise CommandError(msg, scriptname, cmd)

        # shortopts maps long option names to characters. To look up short
        # options, we need to create a reverse mapping.
        shortchars = dict((v, k) for k, v in shortopts.iteritems())

        # The *vargs list and **kwargs dict to build up from the command line
        # arguments
        vargs = []
        kwargs = {}

        doubledashcnt = 0
        singledashcnt = 0
        while argv:
            # Take the next argument
            arg = argv.pop(0)

            if arg == "--":
                doubledashcnt = doubledashcnt + 1
                assert doubledashcnt == 1
                # All arguments following a single hyphen are treated as
                # positional arguments
                vargs.extend(argv)
                break

            elif arg == "-":
                # sys.stdin
                singledashcnt = singledashcnt + 1
                assert singledashcnt == 1
                vargs.append('-')

            elif arg.startswith("--"):
                # Process long option

                value = None
                if "=" in arg:
                    # The argument was specified like --keyword=value
                    name, value = arg[2:].split("=", 1)
                    # strip quotes if value is quoted (--keyword='multiple words')
                    value = value.strip('\'"')

                    default = keywords.get(name)
                    try:
                        value = totype(value, default)
                    except (TypeError, ValueError):
                        type_error(name, value, type(default))
                else:
                    # The argument was not specified with an equals sign...
                    name = arg[2:]
                    default = keywords.get(name)

                    if type(default) is bool:
                        # If this option is a boolean, it doesn't need a value;
                        # specifying it on the command line means "do the
                        # opposite of the default".
                        value = not default
                    else:
                        # The next item in the argument list is the value, i.e.
                        # --keyword value
                        if not argv or argv[0].startswith("-"):
                            # Oops, there isn't a value available... just use
                            # True, assuming this is a flag.
                            value = True
                        else:
                            value = argv.pop(0)

                        try:
                            value = totype(value, default)
                        except (TypeError, ValueError):
                            type_error(name, value, type(default))

                # Store this option
                kwargs[name] = value

            elif arg.startswith("-") and cmd.shortopts:
                # Process short option(s)

                # For each character after the '-'...
                for i in xrange(1, len(arg)):
                    char = arg[i]
                    if char not in shortchars:
                        continue

                    # Get the long option name corresponding to this char
                    name = shortchars[char]

                    default = keywords[name]
                    if type(default) is bool:
                        # If this option is a boolean, it doesn't need a value;
                        # specifying it on the command line means "do the
                        # opposite of the default".
                        kwargs[name] = not default
                    else:
                        # This option requires a value...
                        if i == len(arg)-1:
                            # This is the last character in the list, so the
                            # next argument on the command line is the value.
                            value = argv.pop(0)
                        else:
                            # There are other characters after this one, so
                            # the rest of the characters must represent the
                            # value (i.e. old-style UNIX option like -Nname)
                            value = arg[i+1:]

                        try:
                            kwargs[name] = totype(value, default)
                        except (TypeError, ValueError):
                            type_error(name, value, type(default))
                        break
            else:
                # This doesn't start with "-", so just add it to the list of
                # positional arguments.
                vargs.append(arg)

        return vargs, kwargs

    def parse(self, argv=None):
        """Parses the command and parameters to call from the list of command
        line arguments. Returns a tuple of (scriptname string, Cmd object,
        position arg list, keyword arg dict).

        This method will raise TopHelp if the parser finds that the user
        requested the overall script help, and raise CommandHelp if the user
        requested help on a specific command.

        :param argv: the list of options passed to the command line (sys.argv).
        """

        if argv is None: argv = sys.argv

        scriptname = argv[0]

        if len(argv) < 2 and self.defaultcommand:
            argv.append(self.defaultcommand.name)

        if (len(argv) < 2) or (argv[1] == "-h" or argv[1] == "--help"):
            # Print the documentation for the script
            raise TopHelp(scriptname)

        if argv[1] == "help":
            if len(argv) > 2 and argv[2] in self.commands:
                cmd = self.commands[argv[2]]
                raise CommandHelp(scriptname, cmd)
            raise TopHelp(scriptname)

        if len(argv) > 1 and argv[1] in self.commands:
            # The first argument on the command line (after the script name
            # is the command to run.
            cmd = self.commands[argv[1]]

            if len(argv) > 2 and (argv[2] == "-h" or argv[2] == "--help"):
                raise CommandHelp(scriptname, cmd)

            options = argv[2:]
        else:
            # No known command was specified. If there's a default command,
            # use that.
            cmd = self.defaultcommand
            if cmd is None:
                raise CommandError("No command specified", scriptname)

            options = argv[1:]

        # Parse the rest of the arguments on the command line and use them to
        # call the command function.
        args, kwargs = self.parse_args(scriptname, cmd, options)
        return (scriptname, cmd, args, kwargs)

    def apply(self, scriptname, cmd, args, kwargs):
        """Calls the command function.
        """

        # Create a list of positional arguments: arguments that are either
        # required (not in keywords), or where the default is None (taken to be
        # an optional positional argument). This is different from the Python
        # calling convention, which will fill in keyword arguments with extra
        # positional arguments.

        # Rearrange the arguments into the order Python expects
        newargs = []
        newkwargs = kwargs.copy()
        for name in cmd.argnames:
            if name in cmd.keywords:
                if not args:
                    break
                #keyword arg
                if cmd.has_varargs:
                    #keyword params are not replaced by bare args if the func also has varags
                    #but they must be specified as positional args for proper processing of varargs
                    value = cmd.keywords[name]
                    if name in newkwargs:
                        value = newkwargs[name]
                        del newkwargs[name]
                    newargs.append(value)
                elif not name in newkwargs:
                    newkwargs[name] = args.pop(0)

            else:
                #positional arg
                if name in newkwargs:
                    newargs.append(newkwargs[name])
                    del newkwargs[name]
                else:
                    if args:
                        newargs.append(args.pop(0))
                    else:
                        # This argument is required but we don't have a bare arg to
                        # fill it
                        raise CommandError("Required argument '%s' not given" % name,
                                           scriptname, cmd)
        if args:
            if cmd.has_varargs:
                newargs.extend(args)
            else:
                raise CommandError("Too many arguments to %s: %s" % (cmd.name, " ".join(args)),
                               scriptname, cmd)

        if not cmd.has_kwargs:
            for k in newkwargs:
                if k not in cmd.keywords:
                    raise CommandError("Unknown option --%s" % k,
                                       scriptname, cmd)


        return cmd.fn(*newargs, **newkwargs)

    def run(self, argv=None, main=True, help_on_error=False,
            outfile=sys.stdout, errorfile=sys.stderr, helpfile=sys.stdout,
            errorcode=1):
        """Takes a list of command line arguments, parses it into a command
        name and options, and calls the function corresponding to the command
        with the given arguments.

        :param argv: the list of options passed to the command line (sys.argv).
        :param main: if True, print error messages and exit instead of
            raising an exception.
        :param help_on_error: if True, when an error occurs, print the usage
            help after the error.
        :param errorfile: the file to write error messages to.
        :param helpfile: the file to write usage help to.
        :param errorcode: the exit code to use when calling sys.exit() in the
            case of an error. If this is 0, sys.exit() will not be called.
        """

        try:
            value = self.apply(*self.parse(argv))
            if main and value is not None:
                print value
            return value
        except TopHelp, e:
            if not main: raise
            self.usage(scriptname=e.scriptname, file=helpfile)
        except CommandHelp, e:
            if not main: raise
            self.usage(e.cmd, scriptname=e.scriptname, file=helpfile)
        except CommandError, e:
            if not main: raise
            errorfile.write(str(e) + "\n")
            if help_on_error:
                errorfile.write("\n")
                self.usage(e.cmd, scriptname=e.scriptname, file=helpfile)
            if errorcode:
                sys.exit(errorcode)

    def test(self, argv=None):
        """Takes a list of command line arguments, parses it into a command
        name and options, and prints what the resulting function call would
        look like. This may be useful for testing how command line arguments
        would be passed to your functions.

        :param argv: the list of options passed to the command line (sys.argv).
        """

        try:
            cmd, args, kwargs = self.parse(argv, test=True)
            result = "%s(%s" % (cmd.name, ",".join(repr(a) for a in args))
            if kwargs:
                kws = ", ".join("%s=%r" % (k, v) for k, v in kwargs.iteritems())
                result += ", " + kws
            result += ")"
            print result
        except TopHelp:
            print "(top-level help)"
        except CommandHelp, e:
            print "(help for %s command)" % e.cmd.name


_baker = Baker()
command = _baker.command
run = _baker.run
test = _baker.test
usage = _baker.usage
writeconfig = _baker.writeconfig
openinput = _baker.openinput


if __name__ == "__main__":
    pass