[LC++]State Machines

[Roberto Diaz]

> More easier to do so using array of function pointers

Do you mean in plain C? in such a case I agree. but I have to say also that I
am finding that all the C++ payload usually becames very useful in the
long-term.. 

A scheleton could be something like this: 

class State 
{
  public:
	State (string params);
	state takeSymbol (Symbol s);
  private:
    bool isCompletion;
};
class StateMachine 
{
 public:
	StateMachine (const char *def, cons char *symbolsSource) {}
	state run ();
	bool completion (); // checks if the state machine has completed
	bool parseError (); // the language passed is not parsed by this machine
 private:
 list <state> states; // our array of states
 bool completion;
};

The definition of the a machine ca be a text file,, something like this:

state, simbol0, simbol1,......simboln completion
0  (goto state)1   10 ........  22    no   
........ this for all the states ..........
 
run() just calls the first entry of the array states .takeSymbol() wich in
turn returns or a state (an index) or the constant state::completion/state::noaccept (for example)..

Then just define the state machine in a text file and:

StateMachine m("path", "source");
m.run();  
if (m.completion()) {}
if (m.parseError()) {}

You have a general state machine (for regular grammars)..

-- 
Saludos

Roberto Díaz <roberto at vivaldi.dhis.org>

PLEASE HELP SAVE faqs.org!
http://www.faqs.org/save_faqs-org.html