[SYSTEMDS-3838] Fix unsupported expressions of boolean literals

This patch removes an unnecessary parser error when encountering
binary expressions of boolean literals. Internally we anyway handle
such expressions (which often occur after constant propagation).

Author: mboehm7

src/main/java/org/apache/sysds/parser/DMLTranslator.java

@@ -1835,14 +1835,12 @@ private Hop processBooleanExpression(BooleanExpression source, DataIdentifier ta
 			constRight = (source.getRight().getOutput() instanceof ConstIdentifier);
 		}
 
-		if (constLeft || constRight) {
-			throw new RuntimeException(source.printErrorLocation() + "Boolean expression with constant unsupported");
-		}
-
-		Hop left = processExpression(source.getLeft(), null, hops);
+		Hop left = !constLeft ? processExpression(source.getLeft(), null, hops) : 
+			new LiteralOp(Boolean.valueOf(source.getLeft().getText().toLowerCase()));
 		Hop right = null;
 		if (source.getRight() != null) {
-			right = processExpression(source.getRight(), null, hops);
+			right = !constRight ? processExpression(source.getRight(), null, hops) :
+				new LiteralOp(Boolean.valueOf(source.getRight().getText().toLowerCase()));
 		}
 
 		//prepare target identifier and ensure that output type is boolean 

src/test/java/org/apache/sysds/test/functions/misc/BooleanExpressionTest.java

@@ -0,0 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.sysds.test.functions.misc;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import org.apache.sysds.test.AutomatedTestBase;
+import org.apache.sysds.test.TestConfiguration;
+import org.apache.sysds.test.TestUtils;
+import org.junit.Test;
+
+public class BooleanExpressionTest extends AutomatedTestBase {
+	private final static String TEST_NAME1 = "booleanExpr";
+	private final static String TEST_DIR = "functions/misc/";
+	private final static String TEST_CLASS_DIR = TEST_DIR + BooleanExpressionTest.class.getSimpleName() + "/";
+
+	@Override
+	public void setUp() {
+		TestUtils.clearAssertionInformation();
+		addTestConfiguration(TEST_NAME1, new TestConfiguration(TEST_CLASS_DIR, TEST_NAME1, new String[] {}));
+	}
+
+	@Test
+	public void testPrintNotExpressionTest() {
+		TestConfiguration config = getTestConfiguration(TEST_NAME1);
+		loadTestConfiguration(config);
+		String HOME = SCRIPT_DIR + TEST_DIR;
+		fullDMLScriptName = HOME + TEST_NAME1 + ".dml";
+		try{
+			programArgs = new String[]{};
+			setOutputBuffering(true);
+			String out = runTest(null).toString();
+			assertTrue(out.contains("FALSE\nTRUE")
+					|| out.contains("FALSE\r\nTRUE"));
+		}
+		catch(Exception e){
+			e.printStackTrace();
+			fail();
+		}
+	}
+}

src/test/scripts/functions/misc/booleanExpr.dml

@@ -0,0 +1,23 @@
+#-------------------------------------------------------------
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+# 
+#   http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+#-------------------------------------------------------------
+
+print(TRUE & FALSE);
+print(TRUE & !FALSE);