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84 lines
3.1 KiB
TeX
84 lines
3.1 KiB
TeX
\section{\module{getopt} ---
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Parser for command line options.}
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\declaremodule{standard}{getopt}
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\modulesynopsis{Parser for command line options.}
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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{} \cfunction{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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This module provides a single function and an exception:
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\begin{funcdesc}{getopt}{args, options\optional{, long_options}}
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Parses command line options and parameter list. \var{args} is the
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argument list to be parsed, without the leading reference to the
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running program. Typically, this means \samp{sys.argv[1:]}.
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\var{options} is the string of option letters that the script wants to
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recognize, with options that require an argument followed by a colon
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(i.e., the same format that \UNIX{} \cfunction{getopt()} uses). If
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specified, \var{long_options} is a list of strings with the names of
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the long options which should be supported. The leading
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\code{'-}\code{-'} characters should not be included in the option
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name. Options which require an argument should be followed by an
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equal sign (\code{'='}).
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The return value consists of two elements: the first is a list of
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\code{(\var{option}, \var{value})} pairs; the second is the list of
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program arguments left after the option list was stripped (this is a
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trailing slice of the first argument).
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Each option-and-value pair returned has the option as its first
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element, prefixed with a hyphen (e.g., \code{'-x'}), and the option
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argument as its second element, or an empty string if the option has
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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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\end{funcdesc}
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\begin{excdesc}{error}
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This is raised when an unrecognized option is found in the argument
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list or 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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\end{excdesc}
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An example using only \UNIX{} style options:
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\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}
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Using long option names is equally easy:
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\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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'')]
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>>> args
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['a1', 'a2']
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>>>
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\end{verbatim}
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