dacceptor (n) - Linux Manuals

dacceptor: Create and use deterministic acceptors


grammar::fa::dacceptor - Create and use deterministic acceptors


package require Tcl 8.4

package require snit

package require struct::set

package require grammar::fa::dacceptor ?0.1.1?

::grammar::fa::dacceptor daName fa ?-any any?

daName option ?arg arg ...?

daName destroy

daName accept? symbols


This package provides a class for acceptors constructed from deterministic finite automatons (DFA). Acceptors are objects which can be given a string of symbols and tell if the DFA they are constructed from would accept that string. For the actual creation of the DFAs the acceptors are based on we have the packages grammar::fa and grammar::fa::op.


The package exports the API described here.
::grammar::fa::dacceptor daName fa ?-any any?
Creates a new deterministic acceptor with an associated global Tcl command whose name is daName. This command may be used to invoke various operations on the acceptor. It has the following general form:
daName option ?arg arg ...?
Option and the args determine the exact behavior of the command. See section ACCEPTOR METHODS for more explanations.

The acceptor will be based on the deterministic finite automaton stored in the object fa. It will keep a copy of the relevant data of the FA in its own storage, in a form easy to use for its purposes. This also means that changes made to the fa after the construction of the acceptor will not influence the acceptor.

If any has been specified, then the acceptor will convert all symbols in the input which are unknown to the base FA to that symbol before proceeding with the processing.


All acceptors provide the following methods for their manipulation:

daName destroy
Destroys the automaton, including its storage space and associated command.
daName accept? symbols
Takes the list of symbols and checks if the FA the acceptor is based on would accept it. The result is a boolean value. True is returned if the symbols are accepted, and False otherwise. Note that bogus symbols in the input are either translated to the any symbol (if specified), or cause the acceptance test to simply fail. No errors will be thrown. The method will process only just that prefix of the input which is enough to fully determine (non-)acceptance.



This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category grammar_fa 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.


acceptance, acceptor, automaton, finite automaton, grammar, parsing, regular expression, regular grammar, regular languages, state, transducer


Grammars and finite automata


Copyright (c) 2004 Andreas Kupries <andreas_kupries [at] users.sourceforge.net>