term::receive::bind -
Keyboard dispatch from terminals
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
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.
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.
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.
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.
This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such in the category
term of the
http://sourceforge.net/tracker/?group_id=12883.
Please also report any ideas for enhancements you may have for either
package and/or documentation.
terminal, control, character input, listener, receiver, dispatcher