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"""distutils.fancy_getopt
Wrapper around the standard getopt module that provides the following
additional features:
* short and long options are tied together
* options have help strings, so fancy_getopt could potentially
create a complete usage summary
* options set attributes of a passed-in object
"""
import sys, string, re
import getopt
from distutils.errors import *
# Much like command_re in distutils.core, this is close to but not quite
# the same as a Python NAME -- except, in the spirit of most GNU
# utilities, we use '-' in place of '_'. (The spirit of LISP lives on!)
# The similarities to NAME are again not a coincidence...
longopt_pat = r'[a-zA-Z](?:[a-zA-Z0-9-]*)'
longopt_re = re.compile(r'^%s$' % longopt_pat)
# For recognizing "negative alias" options, eg. "quiet=!verbose"
neg_alias_re = re.compile("^(%s)=!(%s)$" % (longopt_pat, longopt_pat))
# This is used to translate long options to legitimate Python identifiers
# (for use as attributes of some object).
longopt_xlate = str.maketrans('-', '_')
class FancyGetopt:
"""Wrapper around the standard 'getopt()' module that provides some
handy extra functionality:
* short and long options are tied together
* options have help strings, and help text can be assembled
from them
* options set attributes of a passed-in object
* boolean options can have "negative aliases" -- eg. if
--quiet is the "negative alias" of --verbose, then "--quiet"
on the command line sets 'verbose' to false
"""
def __init__(self, option_table=None):
# The option table is (currently) a list of tuples. The
# tuples may have 3 or four values:
# (long_option, short_option, help_string [, repeatable])
# if an option takes an argument, its long_option should have '='
# appended; short_option should just be a single character, no ':'
# in any case. If a long_option doesn't have a corresponding
# short_option, short_option should be None. All option tuples
# must have long options.
self.option_table = option_table
# 'option_index' maps long option names to entries in the option
# table (ie. those 3-tuples).
self.option_index = {}
if self.option_table:
self._build_index()
# 'alias' records (duh) alias options; {'foo': 'bar'} means
# --foo is an alias for --bar
self.alias = {}
# 'negative_alias' keeps track of options that are the boolean
# opposite of some other option
self.negative_alias = {}
# These keep track of the information in the option table. We
# don't actually populate these structures until we're ready to
# parse the command-line, since the 'option_table' passed in here
# isn't necessarily the final word.
self.short_opts = []
self.long_opts = []
self.short2long = {}
self.attr_name = {}
self.takes_arg = {}
# And 'option_order' is filled up in 'getopt()'; it records the
# original order of options (and their values) on the command-line,
# but expands short options, converts aliases, etc.
self.option_order = []
def _build_index(self):
self.option_index.clear()
for option in self.option_table:
self.option_index[option[0]] = option
def set_option_table(self, option_table):
self.option_table = option_table
self._build_index()
def add_option(self, long_option, short_option=None, help_string=None):
if long_option in self.option_index:
raise DistutilsGetoptError(
"option conflict: already an option '%s'" % long_option)
else:
option = (long_option, short_option, help_string)
self.option_table.append(option)
self.option_index[long_option] = option
def has_option(self, long_option):
"""Return true if the option table for this parser has an
option with long name 'long_option'."""
return long_option in self.option_index
def get_attr_name(self, long_option):
"""Translate long option name 'long_option' to the form it
has as an attribute of some object: ie., translate hyphens
to underscores."""
return long_option.translate(longopt_xlate)
def _check_alias_dict(self, aliases, what):
assert isinstance(aliases, dict)
for (alias, opt) in aliases.items():
if alias not in self.option_index:
raise DistutilsGetoptError(("invalid %s '%s': "
"option '%s' not defined") % (what, alias, alias))
if opt not in self.option_index:
raise DistutilsGetoptError(("invalid %s '%s': "
"aliased option '%s' not defined") % (what, alias, opt))
def set_aliases(self, alias):
"""Set the aliases for this option parser."""
self._check_alias_dict(alias, "alias")
self.alias = alias
def set_negative_aliases(self, negative_alias):
"""Set the negative aliases for this option parser.
'negative_alias' should be a dictionary mapping option names to
option names, both the key and value must already be defined
in the option table."""
self._check_alias_dict(negative_alias, "negative alias")
self.negative_alias = negative_alias
def _grok_option_table(self):
"""Populate the various data structures that keep tabs on the
option table. Called by 'getopt()' before it can do anything
worthwhile.
"""
self.long_opts = []
self.short_opts = []
self.short2long.clear()
self.repeat = {}
for option in self.option_table:
if len(option) == 3:
long, short, help = option
repeat = 0
elif len(option) == 4:
long, short, help, repeat = option
else:
# the option table is part of the code, so simply
# assert that it is correct
raise ValueError("invalid option tuple: %r" % (option,))
# Type- and value-check the option names
if not isinstance(long, str) or len(long) < 2:
raise DistutilsGetoptError(("invalid long option '%s': "
"must be a string of length >= 2") % long)
if (not ((short is None) or
(isinstance(short, str) and len(short) == 1))):
raise DistutilsGetoptError("invalid short option '%s': "
"must a single character or None" % short)
self.repeat[long] = repeat
self.long_opts.append(long)
if long[-1] == '=': # option takes an argument?
if short: short = short + ':'
long = long[0:-1]
self.takes_arg[long] = 1
else:
# Is option is a "negative alias" for some other option (eg.
# "quiet" == "!verbose")?
alias_to = self.negative_alias.get(long)
if alias_to is not None:
if self.takes_arg[alias_to]:
raise DistutilsGetoptError(
"invalid negative alias '%s': "
"aliased option '%s' takes a value"
% (long, alias_to))
self.long_opts[-1] = long # XXX redundant?!
self.takes_arg[long] = 0
# If this is an alias option, make sure its "takes arg" flag is
# the same as the option it's aliased to.
alias_to = self.alias.get(long)
if alias_to is not None:
if self.takes_arg[long] != self.takes_arg[alias_to]:
raise DistutilsGetoptError(
"invalid alias '%s': inconsistent with "
"aliased option '%s' (one of them takes a value, "
"the other doesn't"
% (long, alias_to))
# Now enforce some bondage on the long option name, so we can
# later translate it to an attribute name on some object. Have
# to do this a bit late to make sure we've removed any trailing
# '='.
if not longopt_re.match(long):
raise DistutilsGetoptError(
"invalid long option name '%s' "
"(must be letters, numbers, hyphens only" % long)
self.attr_name[long] = self.get_attr_name(long)
if short:
self.short_opts.append(short)
self.short2long[short[0]] = long
def getopt(self, args=None, object=None):
"""Parse command-line options in args. Store as attributes on object.
If 'args' is None or not supplied, uses 'sys.argv[1:]'. If
'object' is None or not supplied, creates a new OptionDummy
object, stores option values there, and returns a tuple (args,
object). If 'object' is supplied, it is modified in place and
'getopt()' just returns 'args'; in both cases, the returned
'args' is a modified copy of the passed-in 'args' list, which
is left untouched.
"""
if args is None:
args = sys.argv[1:]
if object is None:
object = OptionDummy()
created_object = True
else:
created_object = False
self._grok_option_table()
short_opts = ' '.join(self.short_opts)
try:
opts, args = getopt.getopt(args, short_opts, self.long_opts)
except getopt.error as msg:
raise DistutilsArgError(msg)
for opt, val in opts:
if len(opt) == 2 and opt[0] == '-': # it's a short option
opt = self.short2long[opt[1]]
else:
assert len(opt) > 2 and opt[:2] == '--'
opt = opt[2:]
alias = self.alias.get(opt)
if alias:
opt = alias
if not self.takes_arg[opt]: # boolean option?
assert val == '', "boolean option can't have value"
alias = self.negative_alias.get(opt)
if alias:
opt = alias
val = 0
else:
val = 1
attr = self.attr_name[opt]
# The only repeating option at the moment is 'verbose'.
# It has a negative option -q quiet, which should set verbose = 0.
if val and self.repeat.get(attr) is not None:
val = getattr(object, attr, 0) + 1
setattr(object, attr, val)
self.option_order.append((opt, val))
# for opts
if created_object:
return args, object
else:
return args
def get_option_order(self):
"""Returns the list of (option, value) tuples processed by the
previous run of 'getopt()'. Raises RuntimeError if
'getopt()' hasn't been called yet.
"""
if self.option_order is None:
raise RuntimeError("'getopt()' hasn't been called yet")
else:
return self.option_order
def generate_help(self, header=None):
"""Generate help text (a list of strings, one per suggested line of
output) from the option table for this FancyGetopt object.
"""
# Blithely assume the option table is good: probably wouldn't call
# 'generate_help()' unless you've already called 'getopt()'.
# First pass: determine maximum length of long option names
max_opt = 0
for option in self.option_table:
long = option[0]
short = option[1]
l = len(long)
if long[-1] == '=':
l = l - 1
if short is not None:
l = l + 5 # " (-x)" where short == 'x'
if l > max_opt:
max_opt = l
opt_width = max_opt + 2 + 2 + 2 # room for indent + dashes + gutter
# Typical help block looks like this:
# --foo controls foonabulation
# Help block for longest option looks like this:
# --flimflam set the flim-flam level
# and with wrapped text:
# --flimflam set the flim-flam level (must be between
# 0 and 100, except on Tuesdays)
# Options with short names will have the short name shown (but
# it doesn't contribute to max_opt):
# --foo (-f) controls foonabulation
# If adding the short option would make the left column too wide,
# we push the explanation off to the next line
# --flimflam (-l)
# set the flim-flam level
# Important parameters:
# - 2 spaces before option block start lines
# - 2 dashes for each long option name
# - min. 2 spaces between option and explanation (gutter)
# - 5 characters (incl. space) for short option name
# Now generate lines of help text. (If 80 columns were good enough
# for Jesus, then 78 columns are good enough for me!)
line_width = 78
text_width = line_width - opt_width
big_indent = ' ' * opt_width
if header:
lines = [header]
else:
lines = ['Option summary:']
for option in self.option_table:
long, short, help = option[:3]
text = wrap_text(help, text_width)
if long[-1] == '=':
long = long[0:-1]
# Case 1: no short option at all (makes life easy)
if short is None:
if text:
lines.append(" --%-*s %s" % (max_opt, long, text[0]))
else:
lines.append(" --%-*s " % (max_opt, long))
# Case 2: we have a short option, so we have to include it
# just after the long option
else:
opt_names = "%s (-%s)" % (long, short)
if text:
lines.append(" --%-*s %s" %
(max_opt, opt_names, text[0]))
else:
lines.append(" --%-*s" % opt_names)
for l in text[1:]:
lines.append(big_indent + l)
return lines
def print_help(self, header=None, file=None):
if file is None:
file = sys.stdout
for line in self.generate_help(header):
file.write(line + "\n")
def fancy_getopt(options, negative_opt, object, args):
parser = FancyGetopt(options)
parser.set_negative_aliases(negative_opt)
return parser.getopt(args, object)
WS_TRANS = {ord(_wschar) : ' ' for _wschar in string.whitespace}
def wrap_text(text, width):
"""wrap_text(text : string, width : int) -> [string]
Split 'text' into multiple lines of no more than 'width' characters
each, and return the list of strings that results.
"""
if text is None:
return []
if len(text) <= width:
return [text]
text = text.expandtabs()
text = text.translate(WS_TRANS)
chunks = re.split(r'( +|-+)', text)
chunks = [ch for ch in chunks if ch] # ' - ' results in empty strings
lines = []
while chunks:
cur_line = [] # list of chunks (to-be-joined)
cur_len = 0 # length of current line
while chunks:
l = len(chunks[0])
if cur_len + l <= width: # can squeeze (at least) this chunk in
cur_line.append(chunks[0])
del chunks[0]
cur_len = cur_len + l
else: # this line is full
# drop last chunk if all space
if cur_line and cur_line[-1][0] == ' ':
del cur_line[-1]
break
if chunks: # any chunks left to process?
# if the current line is still empty, then we had a single
# chunk that's too big too fit on a line -- so we break
# down and break it up at the line width
if cur_len == 0:
cur_line.append(chunks[0][0:width])
chunks[0] = chunks[0][width:]
# all-whitespace chunks at the end of a line can be discarded
# (and we know from the re.split above that if a chunk has
# *any* whitespace, it is *all* whitespace)
if chunks[0][0] == ' ':
del chunks[0]
# and store this line in the list-of-all-lines -- as a single
# string, of course!
lines.append(''.join(cur_line))
return lines
def translate_longopt(opt):
"""Convert a long option name to a valid Python identifier by
changing "-" to "_".
"""
return opt.translate(longopt_xlate)
class OptionDummy:
"""Dummy class just used as a place to hold command-line option
values as instance attributes."""
def __init__(self, options=[]):
"""Create a new OptionDummy instance. The attributes listed in
'options' will be initialized to None."""
for opt in options:
setattr(self, opt, None)
if __name__ == "__main__":
text = """\
Tra-la-la, supercalifragilisticexpialidocious.
How *do* you spell that odd word, anyways?
(Someone ask Mary -- she'll know [or she'll
say, "How should I know?"].)"""
for w in (10, 20, 30, 40):
print("width: %d" % w)
print("\n".join(wrap_text(text, w)))
print()
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