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
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>