opencog-atomspace / tests / atoms / core / FreeLinkUTest.cxxtest

/*
 * tests/atoms/core/FreeLinkUTest.cxxtest
 *
 * Copyright (C) 2015 Linas Vepstas
 * All Rights Reserved
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License v3 as
 * published by the Free Software Foundation and including the exceptions
 * at http://opencog.org/wiki/Licenses
 *
 * This program 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 Affero General Public License
 * along with this program; if not, write to:
 * Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <opencog/guile/SchemeEval.h>
#include <opencog/atomspace/AtomSpace.h>
#include <opencog/atoms/free/FreeLink.h>
#include <opencog/atoms/scope/VariableList.h>
#include <opencog/util/Logger.h>

using namespace opencog;

class FreeLinkUTest: public CxxTest::TestSuite
{
private:
	AtomSpacePtr as;
	SchemeEval* eval;

public:
	FreeLinkUTest(void)
	{
		logger().set_level(Logger::DEBUG);
		logger().set_print_to_stdout_flag(true);

		as = createAtomSpace();
		eval = SchemeEval::get_scheme_evaluator(as);
	}

	~FreeLinkUTest()
	{
		// Erase the log file if no assertions failed.
		if (!CxxTest::TestTracker::tracker().suiteFailed())
			std::remove(logger().get_filename().c_str());
	}

	void setUp(void);
	void tearDown(void);

	void test_unquote(void);
	void test_deunquote(void);
	void test_binding(void);
	void test_getlink(void);
};

void FreeLinkUTest::tearDown(void)
{
	as->clear();
}

void FreeLinkUTest::setUp(void)
{
	as->clear();
}

/*
 * FreeLink free-variable extraction test.  Test UnquoteLink.
 */
void FreeLinkUTest::test_unquote(void)
{
	logger().debug("BEGIN TEST: %s", __FUNCTION__);

	// ---------
	Handle vx = eval->eval_h("(VariableNode \"$x\")");
	Handle vz = eval->eval_h("(VariableNode \"$z\")");
	Handle unq = eval->eval_h(
		"(OrderedLink (VariableNode \"$x\")"
		"	(QuoteLink (ListLink (VariableNode \"$y\")"
		"		(UnquoteLink (VariableNode \"$z\")))))"
	);

	FreeVariables fv;
	fv.find_variables(unq);
	HandleSeq vars = fv.varseq;

	printf("expecting Variable $x: %s\n", vars[0]->to_short_string().c_str());
	printf("expecting Variable $z: %s\n", vars[1]->to_short_string().c_str());

	// Expecting only two variables $x and $z, because $y is quoted.
	// Expecting the order to be preserved: i.e. $x before $z
	TS_ASSERT_EQUALS(vars.size(), 2);
	TS_ASSERT_EQUALS(vars[0], vx);
	TS_ASSERT_EQUALS(vars[1], vz);

	// ---------
	logger().debug("END TEST: %s", __FUNCTION__);
}

/*
 * FreeLink free-variable extraction test.  Test multiple,
 * recursive UnquoteLinks.
 */
void FreeLinkUTest::test_deunquote(void)
{
	logger().debug("BEGIN TEST: %s", __FUNCTION__);

	// ---------
	Handle vx = eval->eval_h("(VariableNode \"$x\")");
	Handle vz = eval->eval_h("(VariableNode \"$z\")");
	Handle vu = eval->eval_h("(VariableNode \"$u\")");
	Handle unq = eval->eval_h(
		"(OrderedLink (VariableNode \"$x\")"
		"	(QuoteLink (ListLink (VariableNode \"$y\")"
		"		(UnquoteLink (VariableNode \"$z\"))"
		"		(VariableNode \"$w\")"
		"		(UnquoteLink (VariableNode \"$u\"))"
		"		(VariableNode \"$t\"))))"
	);

	FreeVariables fv;
	fv.find_variables(unq);
	HandleSeq vars = fv.varseq;

	printf("expect Var $x: %s\n", vars[0]->to_short_string().c_str());
	printf("expect Var $z: %s\n", vars[1]->to_short_string().c_str());
	printf("expect Var $u: %s\n", vars[2]->to_short_string().c_str());

	// Expecting only three variables $x, $z, $u because all the
	// others are quoted.  Expecting the order to be preserved:
	// i.e. $x then $z then $u.
	TS_ASSERT_EQUALS(vars.size(), 3);
	TS_ASSERT_EQUALS(vars[0], vx);
	TS_ASSERT_EQUALS(vars[1], vz);
	TS_ASSERT_EQUALS(vars[2], vu);

	// ---------
	logger().debug("END TEST: %s", __FUNCTION__);
}

/*
 * FreeLink free-variable extraction test.  Test bound variables.
 */
void FreeLinkUTest::test_binding(void)
{
	logger().debug("BEGIN TEST: %s", __FUNCTION__);

	// ---------
	Handle vx = eval->eval_h("(VariableNode \"$x\")");
	Handle vz = eval->eval_h("(VariableNode \"$z\")");
	Handle unq = eval->eval_h(
		"(OrderedLink (VariableNode \"$x\")"
		"	(LambdaLink (VariableList (VariableNode \"$y\"))"
		"		(ListLink (VariableNode \"$z\"))))"
	);

	FreeVariables fv;
	fv.find_variables(unq);
	HandleSeq vars = fv.varseq;

	printf("expecting free $x: %s\n", vars[0]->to_short_string().c_str());
	printf("expecting free $z: %s\n", vars[1]->to_short_string().c_str());

	// Expecting only two variables $x and $z, because $y is quoted.
	// Expecting the order to be preserved: i.e. $x before $z
	TS_ASSERT_EQUALS(vars.size(), 2);
	TS_ASSERT_EQUALS(vars[0], vx);
	TS_ASSERT_EQUALS(vars[1], vz);

	// ---------
	logger().debug("END TEST: %s", __FUNCTION__);
}

/*
 * FreeLink free-variable extraction test.  Test MeetLink.
 */
void FreeLinkUTest::test_getlink(void)
{
	logger().debug("BEGIN TEST: %s", __FUNCTION__);

	// ---------
	Handle vx = eval->eval_h("(VariableNode \"$x\")");
	Handle vz = eval->eval_h("(VariableNode \"$z\")");
	Handle unq = eval->eval_h(
		"(OrderedLink (VariableNode \"$x\")"
		"	(MeetLink (VariableList (VariableNode \"$ya\")"
		"			(VariableNode \"$yb\")"
		"			(VariableNode \"$yc\")"
		"			(VariableNode \"$yd\"))"
		"		(ListLink (VariableNode \"$ya\")"
		"			(VariableNode \"$yb\")"
		"			(VariableNode \"$z\")"
		"			(VariableNode \"$yc\")"
		"			(VariableNode \"$yd\"))))"
	);

	FreeVariables fv;
	fv.find_variables(unq);
	HandleSeq vars = fv.varseq;

	printf("expecting meet $x: %s\n", vars[0]->to_short_string().c_str());
	printf("expecting meet $z: %s\n", vars[1]->to_short_string().c_str());

	// Expecting only two variables $x and $z, because $y variables are bound.
	// Expecting the order to be preserved: i.e. $x before $z
	TS_ASSERT_EQUALS(vars.size(), 2);
	TS_ASSERT_EQUALS(vars[0], vx);
	TS_ASSERT_EQUALS(vars[1], vz);

	// ---------
	logger().debug("END TEST: %s", __FUNCTION__);
}