NAME

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

SYNOPSIS

       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

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DESCRIPTION

       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.

API

       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.

ACCEPTOR METHODS

       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.

EXAMPLES

BUGS, IDEAS, FEEDBACK

       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  Trackers
       [http://core.tcl.tk/tcllib/reportlist].  Please also report any ideas for enhancements you
       may have for either package and/or documentation.

KEYWORDS

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

CATEGORY

       Grammars and finite automata

COPYRIGHT

       Copyright (c) 2004 Andreas Kupries <andreas_kupries@users.sourceforge.net>