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diff --git a/Doc/lib/libcmd.tex b/Doc/lib/libcmd.tex new file mode 100644 index 0000000..7c4dd4a --- /dev/null +++ b/Doc/lib/libcmd.tex @@ -0,0 +1,134 @@ +% Documentation by ESR +\section{Standard Module \module{cmd}} +\stmodindex{cmd} +\label{module-cmd} + +The \code{Cmd} class provides a simple framework for writing +line-oriented command interpreters. These are often useful for +test harnesses, administrative tools, and prototypes that will +later be wrapped in a more sophisticated interface. + +\begin{classdesc}{Cmd}{} +A \class{Cmd} instance or subclass instance is a line-oriented +interpreter framework. There is no good reason to instantiate Cmd +itself; rather, it's useful as a superclass of an interpreter class +you define yourself in order to inherit Cmd's methods and encapsulate +action functions. +\end{classdesc} + +\subsection{Cmd Objects} +\label{Cmd-objects} + +A \class{Cmd} instance has the following methods: + +\begin{methoddesc}{cmdloop}{intro} +Repeatedly issue a prompt, accept input, parse an initial prefix off +the received input, and dispatch to action methods, passing them the +remainder of the line as argument. + +The optional argument is a banner or intro string to be issued before the +first prompt (this overrides the \member{intro} class member). + +If the \module{readline} module is loaded, input will automatically +inherit Emacs-like history-list editing (e.g. Ctrl-P scrolls back to +the last command, Ctrl-N forward to the next one, Ctrl-F moves the +cursor to the right non-destructively, Ctrl-B moves the cursor to the +left non-destructively, etc.). + +An end-of-file on input is passed back as the string "EOF". + +An interpreter instance will recognize a command name \code{foo} if +and only if it has a method named \method{do_foo}. As a special case, +a line containing only the character `?' is dispatched to the method +\method{do_help}. As another special case, a line containing only the +character `!' is dispatched to the method \method{do_shell} (if such a method +is defined). + +All subclasses of \class{Cmd} inherit a predefined \method{do_help}. +This method, called with an argument \code{bar}, invokes the +corresponding method \method{help_bar}. With no argument, +\method{do_help} lists all available help topics (that is, all +commands with corresponding \code{help_} methods), and also lists any +undocumented commands. +\end{methoddesc} + +\begin{methoddesc}{onecmd}{str} +Interpret the argument as though it had been typed in in +response to the prompt. +\end{methoddesc} + +\begin{methoddesc}{emptyline}{} +Method called when an empty line is entered in response to the prompt. +If this method is not overridden, it repeats the last nonempty command +entered. +\end{methoddesc} + +\begin{methoddesc}{default}{line} +Method called on an input line when the command prefix is not +recognized. If this method is not overridden, it prints an +error message and returns. +\end{methoddesc} + +\begin{methoddesc}{precmd} +Hook method executed just before the input prompt is issued. This method is +a stub in \class{Cmd}; it exists to be overridden by subclasses. +\end{methoddesc} + +\begin{methoddesc}{postcmd} +Hook method executed just after a command dispatch is finished. This +method is a stub in \class{Cmd}; it exists to be overridden by +subclasses. +\end{methoddesc} + +\begin{methoddesc}{preloop} +Hook method executed once when \method{cmdloop()} is called. This method is +a stub in \class{Cmd}; it exists to be overridden by subclasses. +\end{methoddesc} + +\begin{methoddesc}{postloop} +Hook method executed once when \method{cmdloop()} is about to return. This +method is a stub in \class{Cmd}; it exists to be overridden by +subclasses. +\end{methoddesc} + +Instances of \class{Cmd} subclasses have some public instance variables: + +\begin{memberdesc}{prompt} +The prompt issued to solicit input. +\end{memberdesc} + +\begin{memberdesc}{identchars} +The string of characters accepted for the command prefix. +\end{memberdesc} + +\begin{memberdesc}{lastcmd} +The last nonempty command prefix seen. +\end{memberdesc} + +\begin{memberdesc}{intro} +A string to issue as an intro or banner. May be overridden by giving +the \method{cmdloop()} method an argument. +\end{memberdesc} + +\begin{memberdesc}{doc_header} +The header to issue if the help output has a section for documented commands. +\end{memberdesc} + +\begin{memberdesc}{misc_header} +The header to issue if the help output has a section for miscellaneous +help topics (that is, there are \code{help_} methods withoud corresponding +\code{do_} functions). +\end{memberdesc} + +\begin{memberdesc}{undoc_header} +The header to issue if the help output has a section for undocumented +commands (that is, there are \code{do_} methods withoud corresponding +\code{help_} functions). +\end{memberdesc} + +\begin{memberdesc}{ruler} +The character used to draw separator lines under the help-message +headers. If empty, no ruler line is drawn. It defaults to "=". +\end{memberdesc} + + |