mirror of https://github.com/python/cpython.git
86 lines
3.0 KiB
TeX
86 lines
3.0 KiB
TeX
% Module and documentation by Eric S. Raymond, 21 Dec 1998
|
|
|
|
\section{\module{shlex} ---
|
|
Simple lexical analysis.}
|
|
|
|
\declaremodule{standard}{shlex}
|
|
\modulesynopsis{Simple lexical analysis for \UNIX{} shell-like languages.}
|
|
\moduleauthor{Eric S. Raymond}{esr@snark.thyrsus.com}
|
|
\sectionauthor{Eric S. Raymond}{esr@snark.thyrsus.com}
|
|
|
|
\versionadded{1.5.2}
|
|
|
|
The \class{shlex} class makes it easy to write lexical analyzers for
|
|
simple syntaxes resembling that of the \UNIX{} shell. This will often
|
|
be useful for writing minilanguages, e.g.\ in run control files for
|
|
Python applications.
|
|
|
|
\begin{classdesc}{shlex}{\optional{stream}}
|
|
A \class{shlex} instance or subclass instance is a lexical analyzer
|
|
object. The initialization argument, if present, specifies where to
|
|
read characters from. It must be a file- or stream-like object with
|
|
\method{read()} and \method{readline()} methods. If no argument is given,
|
|
input will be taken from \code{sys.stdin}.
|
|
|
|
\end{classdesc}
|
|
|
|
\subsection{shlex Objects \label{shlex-objects}}
|
|
|
|
A \class{shlex} instance has the following methods:
|
|
|
|
\begin{methoddesc}{get_token}{}
|
|
Return a token. If tokens have been stacked using
|
|
\method{push_token()}, pop a token off the stack. Otherwise, read one
|
|
from the input stream. If reading encounters an immediate
|
|
end-of-file, an empty string is returned.
|
|
\end{methoddesc}
|
|
|
|
\begin{methoddesc}{push_token}{str}
|
|
Push the argument onto the token stack.
|
|
\end{methoddesc}
|
|
|
|
Instances of \class{shlex} subclasses have some public instance
|
|
variables which either control lexical analysis or can be used
|
|
for debugging:
|
|
|
|
\begin{memberdesc}{commenters}
|
|
The string of characters that are recognized as comment beginners.
|
|
All characters from the comment beginner to end of line are ignored.
|
|
Includes just \character{\#} by default.
|
|
\end{memberdesc}
|
|
|
|
\begin{memberdesc}{wordchars}
|
|
The string of characters that will accumulate into multi-character
|
|
tokens. By default, includes all \ASCII{} alphanumerics and
|
|
underscore.
|
|
\end{memberdesc}
|
|
|
|
\begin{memberdesc}{whitespace}
|
|
Characters that will be considered whitespace and skipped. Whitespace
|
|
bounds tokens. By default, includes space, tab, linefeed and
|
|
carriage-return.
|
|
\end{memberdesc}
|
|
|
|
\begin{memberdesc}{quotes}
|
|
Characters that will be considered string quotes. The token
|
|
accumulates until the same quote is encountered again (thus, different
|
|
quote types protect each other as in the shall.) By default, includes
|
|
\ASCII{} single and double quotes.
|
|
\end{memberdesc}
|
|
|
|
Note that any character not declared to be a word character,
|
|
whitespace, or a quote will be returned as a single-character token.
|
|
|
|
Quote and comment characters are not recognized within words. Thus,
|
|
the bare words \samp{ain't} and \samp{ain\#t} would be returned as single
|
|
tokens by the default parser.
|
|
|
|
\begin{memberdesc}{lineno}
|
|
Source line number (count of newlines seen so far plus one).
|
|
\end{memberdesc}
|
|
|
|
\begin{memberdesc}{token}
|
|
The token buffer. It may be useful to examine this when catching
|
|
exceptions.
|
|
\end{memberdesc}
|