NAME¶
term::receive::bind - Keyboard dispatch from terminals
SYNOPSIS¶
package require
Tcl 8.4
package require
term::receive::bind ?0.1?
term::receive::bind object ?
map?
object map str cmd
object default cmd
object listen ?
chan?
object unlisten ?
chan?
object reset
object next char
object process str
object eof
DESCRIPTION¶
This package provides a class for the creation of simple dispatchers from
character sequences to actions. Internally each dispatcher is in essence a
deterministic finite automaton with tree structure.
CLASS API¶
The package exports a single command, the class command, enabling the creation
of dispatcher instances. Its API is:
- term::receive::bind object ?map?
- This command creates a new dispatcher object with the name
object, initializes it, and returns the fully qualified name of the
object command as its result.
The argument is a dictionary mapping from strings, i.e. character sequences
to the command prefices to invoke when the sequence is found in the input
stream.
OBJECT API¶
The objects created by the class command provide the methods listed below:
- object map str cmd
- This method adds an additional mapping from the string
str to the action cmd. The mapping will take effect
immediately should the processor be in a prefix of str, or at the
next reset operation. The action is a command prefix and will be invoked
with one argument appended to it, the character sequence causing the
invokation. It is executed in the global namespace.
- object default cmd
- This method defines a default action cmd which will
be invoked whenever an unknown character sequence is encountered. The
command prefix is handled in the same as the regular action defined via
method map.
- object listen ?chan?
- This methods sets up a filevent listener for the channel
with handle chan and invokes the dispatcher object whenever
characters have been received, or EOF was reached.
If not specified chan defaults to stdin.
- object unlisten ?chan?
- This methods removes the filevent listener for the channel
with handle chan.
If not specified chan defaults to stdin.
- object reset
- This method resets the character processor to the beginning
of the tree.
- object next char
- This method causes the character processor to process the
character c. This may simply advance the internal state, or invoke
an associated action for a recognized sequence.
- object process str
- This method causes the character processor to process the
character sequence str, advancing the internal state and invoking
action as necessary. This is a callback for listen.
- object eof
- This method causes the character processor to handle EOF on
the input. This is currently no-op. This is a callback for
listen.
NOTES¶
The simplicity of the DFA means that it is not possible to recognize a character
sequence with has a another recognized character sequence as its prefix.
In other words, the set of recognized strings has to form a
prefix code.
BUGS, IDEAS, FEEDBACK¶
This document, and the package it describes, will undoubtedly contain bugs and
other problems. Please report such in the category
term of the
Tcllib SF Trackers [
http://sourceforge.net/tracker/?group_id=12883].
Please also report any ideas for enhancements you may have for either package
and/or documentation.
KEYWORDS¶
character input, control, dispatcher, listener, receiver, terminal
CATEGORY¶
Terminal control
COPYRIGHT¶
Copyright (c) 2006 Andreas Kupries <andreas_kupries@users.sourceforge.net>