Evaluator.cpp

/************************************************************************
 * Copyright 2008, Strathclyde Planning Group,
 * Department of Computer and Information Sciences,
 * University of Strathclyde, Glasgow, UK
 * http://planning.cis.strath.ac.uk/
 *
 * Maria Fox, Richard Howey and Derek Long - VAL
 * Stephen Cresswell - PDDL Parser
 *
 * This file is part of VAL, the PDDL validator.
 *
 * VAL is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * VAL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with VAL.  If not, see <http://www.gnu.org/licenses/>.
 *
 ************************************************************************/

#include "Evaluator.h"
#include "TypedAnalyser.h"
#include "State.h"
#include "ptree.h"
#include "instantiation.h"
#include "InstPropLinker.h"
#include "Validator.h"

using namespace VAL;

namespace Inst {

Evaluator::Evaluator(Validator * v,const VAL::State * s,Inst::instantiatedOp * op,bool im) : 
		vld(v), value(true), env(toEnv(op)), f(op->getEnv()), state(s),
		equality(VAL::current_analysis->pred_tab.symbol_probe("=")),
		ignoreMetrics(im), context(true)
{};

void Evaluator::visit_preference(preference * p)
{};
					
void Evaluator::visit_simple_goal(simple_goal * s)
{
//	cout << "Evaluating " << *s << " in state " << *state << "\n";
	
	if(EPS(s->getProp()->head)->getParent() == this->equality)
	{
//	cout << "Got equality\n";
		value = ((*f)[s->getProp()->args->front()] == 
						(*f)[s->getProp()->args->back()]);
		
		if(s->getPolarity() == E_NEG)
		{
			value = !value;
		};
		return;
	};

// Evaluate the goal in the state
	const SimpleProposition * sp = vld->pf.buildLiteral(s->getProp(),env);
	value = state->evaluate(sp);
	if(s->getPolarity() == E_NEG)
	{
		value = !value;
	};
//	cout << "Value determined as: " << value << "\n";
};

void Evaluator::visit_qfied_goal(qfied_goal * q)
{
	cout << "Evaluator (line 70): Not handling quantified goals yet!\n";
	
	for(var_symbol_list::const_iterator i = q->getVars()->begin();
			i != q->getVars()->end();++i)
	{
		cout << "Got: " << static_cast<const IDsymbol<var_symbol> *>(*i)->getId() << "\n";
	};
};

void Evaluator::visit_conj_goal(conj_goal * c)
{
	value = true;
	for(goal_list::const_iterator i = c->getGoals()->begin();
		i != c->getGoals()->end();++i)
	{
		(*i)->visit(this);
		if(!value) return;
	};
};
	
void Evaluator::visit_disj_goal(disj_goal * d)
{
	value = false;
	for(goal_list::const_iterator i = d->getGoals()->begin();
		i != d->getGoals()->end();++i)
	{
		(*i)->visit(this);
		if(value) return;
	};
};

void Evaluator::visit_timed_goal(timed_goal * t)
{
	t->getGoal()->visit(this);
};

void Evaluator::visit_imply_goal(imply_goal * ig)
{
	context = !context;
	ig->getAntecedent()->visit(this);
	context = !context;
	if(value)
	{
		ig->getConsequent()->visit(this);
	}
	else value = true;
};

void Evaluator::visit_neg_goal(neg_goal * ng)
{
	context = !context;
	ng->getGoal()->visit(this);
	context = !context;
	value = !value;
};

void Evaluator::visit_event(event * op)
{
	value = true;
	op->precondition->visit(this);
};

void Evaluator::visit_process(process * op)
{
	value = true;
	op->precondition->visit(this);
};


void Evaluator::visit_comparison(comparison * comp)
{
// Note: Could avoid dual visits by doing parallel evaluation with and without metrics
	if(ignoreMetrics) 
	{
		value = context;
	};
// Problem: Really this works for continuous change - should do proper evaluations
// for discretely changing values.
	 double eval = state->evaluate(comp->getLHS(),env)  - state->evaluate(comp->getRHS(),env);
      double tooSmall = 0.00001;

      		switch(comp->getOp())
      		{
      			case E_GREATER:
      				value = (eval > -tooSmall);
      				if(value && eval <= 0)
      				{
      					cout << "Sloppy evaluation disagrees: " << eval << " > 0\n";
      				};
					return;
					
      			case E_GREATEQ:
      				value = (eval >= -tooSmall);
      				if(value && eval < 0)
      				{
      					cout << "Sloppy evaluation disagrees: " << eval << " >= 0\n";
      				};
					return;
					
      			case E_LESS:
      				value = (eval < tooSmall);
      				if(value && eval >= 0)
      				{
      					cout << "Sloppy evaluation disagrees: " << eval << " < 0\n";
      				};
					return;
					
      			case E_LESSEQ:
      				value = (eval <= tooSmall);
      				if(value && eval > 0)
      				{
      					cout << "Sloppy evaluation disagrees: " << eval << " <= 0\n";
      				};
					return;

      			case E_EQUALS:
      				value = (eval < tooSmall && eval > -tooSmall);
      				if(value && eval != 0)
      				{
      					cout << "Sloppy evaluation disagrees: " << eval << " = 0\n";
      				};
					return;
					
      			default:
      				return;
      		}; 
};

void Evaluator::visit_action(action * op)
{
	value = true;
	op->precondition->visit(this);
};

void Evaluator::visit_durative_action(durative_action * da)
{
	value = true;
	da->precondition->visit(this);
};

};