mirror of https://github.com/python/cpython.git
78 lines
2.7 KiB
TeX
78 lines
2.7 KiB
TeX
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% Module and documentation by Eric S. Raymond, 21 Dec 1998
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\section{Standard Module \module{shlex}}
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\stmodindex{shlex}
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\label{module-shlex}
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The \code{shlex} class makes it easy to write lexical analyzers for
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simple syntaxes resembling that of the Unix shell. This will often
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be useful for writing minilanguages, e.g. in run control files for
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Python applications.
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\begin{classdesc}{shlex}{\optional{stream}}
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A \class{shlex} instance or subclass instance is a lexical analyzer
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object. The initialization argument, if present, specifies where to
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read characters from. It must be a file- or stream-like object with
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\method{read} and \method{readline} methods. If no argument is given,
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input will be taken from sys.stdin.
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\end{classdesc}
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\subsection{shlex Objects}
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\label{shlex-objects}
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A \class{shlex} instance has the following methods:
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\begin{methoddesc}{get_token}{}
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Return a token. If tokens have been stacked using \method{push_token},
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pop a token off the stack. Otherwise, read one from the input stream.
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If reading encounters an immediate end-of-file, '' is returned.
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\end{methoddesc}
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\begin{methoddesc}{push_token}{str}
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Push the argument onto the token stack.
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\end{methoddesc}
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Instances of \class{shlex} subclasses have some public instance
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variables which either control lexical analysis or can be used
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for debugging:
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\begin{memberdesc}{commenters}
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The string of characters that are recognized as comment beginners.
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All characters from the comment beginner to end of line are ignored.
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Includes just '#' by default.
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\end{memberdesc}
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\begin{memberdesc}{wordchars}
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The string of characters that will accumulate into multi-character
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tokens. By default, includes all ASCII alphanumerics and underscore.
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\end{memberdesc}
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\begin{memberdesc}{whitespace}
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Characters that will be considered whitespace and skipped. Whitespace
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bounds tokens. By default, includes space and tab and linefeed and
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carriage-return.
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\end{memberdesc}
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\begin{memberdesc}{quotes}
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Characters that will be considered string quotes. The token
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accumulates until the same quote is encountered again (thus, different
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quote types protect each other as in the shall.) By default, includes
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ASCII single and double quotes.
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\end{memberdesc}
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Note that any character not declared to be a word character,
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whitespace, or a quote will be returned as a single-character token.
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Quote and comment characters are not recognized within words. Thus,
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the bare words ``ain't'' and ``ain#t'' would be returned as single
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tokens by the default parser.
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\begin{memberdesc}{lineno}
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Source line number (count of newlines seen so far plus one).
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\end{memberdesc}
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\begin{memberdesc}{token}
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The token buffer. It may be useful to examine this when catching exceptions.
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\end{memberdesc}
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