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83 lines
3.0 KiB
TeX
83 lines
3.0 KiB
TeX
\section{Standard Module \sectcode{getopt}}
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\stmodindex{getopt}
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This module helps scripts to parse the command line arguments in
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\code{sys.argv}.
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It supports the same conventions as the \UNIX{}
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\code{getopt()}
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function (including the special meanings of arguments of the form
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`\code{-}' and `\code{-}\code{-}').
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% That's to fool latex2html into leaving the two hyphens alone!
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Long options similar to those supported by
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GNU software may be used as well via an optional third argument.
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It defines the function
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\code{getopt.getopt(args, options [, long_options])}
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and the exception
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\code{getopt.error}.
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The first argument to
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\code{getopt()}
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is the argument list passed to the script with its first element
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chopped off (i.e.,
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\code{sys.argv[1:]}).
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The second argument is the string of option letters that the
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script wants to recognize, with options that require an argument
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followed by a colon (i.e., the same format that \UNIX{}
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\code{getopt()}
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uses).
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The third option, if specified, is a list of strings with the names of
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the long options which should be supported. The leading \code{'-}\code{-'}
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characters should not be included in the option name. Options which
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require an argument should be followed by an equal sign (\code{'='}).
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The return value consists of two elements: the first is a list of
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option-and-value pairs; the second is the list of program arguments
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left after the option list was stripped (this is a trailing slice of the
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first argument).
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Each option-and-value pair returned has the option as its first element,
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prefixed with a hyphen (e.g.,
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\code{'-x'}),
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and the option argument as its second element, or an empty string if the
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option has no argument.
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The options occur in the list in the same order in which they were
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found, thus allowing multiple occurrences. Long and short options may
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be mixed.
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An example using only \UNIX{} style options:
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\bcode\begin{verbatim}
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>>> import getopt, string
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>>> args = string.split('-a -b -cfoo -d bar a1 a2')
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>>> args
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['-a', '-b', '-cfoo', '-d', 'bar', 'a1', 'a2']
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>>> optlist, args = getopt.getopt(args, 'abc:d:')
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>>> optlist
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[('-a', ''), ('-b', ''), ('-c', 'foo'), ('-d', 'bar')]
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>>> args
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['a1', 'a2']
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>>>
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\end{verbatim}\ecode
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Using long option names is equally easy:
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\bcode\begin{verbatim}
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>>> s = '--condition=foo --testing --output-file abc.def -x a1 a2'
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>>> args = string.split(s)
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>>> args
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['--condition=foo', '--testing', '--output-file', 'abc.def', '-x', 'a1', 'a2']
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>>> optlist, args = getopt.getopt(args, 'x', [
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... 'condition=', 'output-file=', 'testing'])
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>>> optlist
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[('--condition', 'foo'), ('--testing', ''), ('--output-file', 'abc.def'), ('-x', '')]
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>>> args
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['a1', 'a2']
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>>>
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\end{verbatim}\ecode
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The exception
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\code{getopt.error = 'getopt.error'}
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is raised when an unrecognized option is found in the argument list or
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when an option requiring an argument is given none.
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The argument to the exception is a string indicating the cause of the
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error. For long options, an argument given to an option which does
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not require one will also cause this exception to be raised.
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