Introduce ProgramPartParser to simplify construction of parts of programs

src/main/java/at/ac/tuwien/kr/alpha/grounder/Substitution.java

@@ -1,5 +1,5 @@
-/**
- * Copyright (c) 2016-2019, the Alpha Team.
+/*
+ * Copyright (c) 2016-2020, the Alpha Team.
  * All rights reserved.
  *
  * Additional changes made by Siemens.
@@ -27,29 +27,23 @@
  */
 package at.ac.tuwien.kr.alpha.grounder;
 
-import at.ac.tuwien.kr.alpha.antlr.ASPCore2Lexer;
-import at.ac.tuwien.kr.alpha.antlr.ASPCore2Parser;
 import at.ac.tuwien.kr.alpha.common.atoms.Atom;
 import at.ac.tuwien.kr.alpha.common.atoms.Literal;
 import at.ac.tuwien.kr.alpha.common.terms.ConstantTerm;
 import at.ac.tuwien.kr.alpha.common.terms.FunctionTerm;
 import at.ac.tuwien.kr.alpha.common.terms.Term;
 import at.ac.tuwien.kr.alpha.common.terms.VariableTerm;
-import at.ac.tuwien.kr.alpha.grounder.parser.ParseTreeVisitor;
-import org.antlr.v4.runtime.CharStreams;
-import org.antlr.v4.runtime.CommonTokenStream;
-import org.antlr.v4.runtime.RecognitionException;
-import org.antlr.v4.runtime.misc.ParseCancellationException;
+import at.ac.tuwien.kr.alpha.grounder.parser.ProgramPartParser;
 
-import java.util.Collections;
 import java.util.Map;
 import java.util.Objects;
 import java.util.TreeMap;
 
 import static at.ac.tuwien.kr.alpha.Util.oops;
 
 public class Substitution {
- private static final ParseTreeVisitor VISITOR = new ParseTreeVisitor(Collections.emptyMap(), false);
+
+ private static final ProgramPartParser PROGRAM_PART_PARSER = new ProgramPartParser();
 
  protected TreeMap<VariableTerm, Term> substitution;
 
@@ -198,24 +192,12 @@ public static Substitution fromString(String substitution) {
  for (String assignment : assignments) {
  String keyVal[] = assignment.split("->");
  VariableTerm variable = VariableTerm.getInstance(keyVal[0]);
- Term assignedTerm = parseTerm(keyVal[1]);
+ Term assignedTerm = PROGRAM_PART_PARSER.parseTerm(keyVal[1]);
  ret.put(variable, assignedTerm);
  }
  return ret;
  }
 
- private static Term parseTerm(String s) {
- try {
- final ASPCore2Parser parser = new ASPCore2Parser(new CommonTokenStream(new ASPCore2Lexer(CharStreams.fromString(s))));
- return (Term)VISITOR.visit(parser.term());
- } catch (RecognitionException | ParseCancellationException e) {
- // If there were issues parsing the given string, we
- // throw something that suggests that the input string
- // is malformed.
- throw new IllegalArgumentException("Could not parse term.", e);
- }
- }
-
  @Override
  public boolean equals(Object o) {
  if (this == o) {

src/main/java/at/ac/tuwien/kr/alpha/grounder/parser/ProgramPartParser.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2018-2020, the Alpha Team.
+ * All rights reserved.
+ *
+ * Additional changes made by Siemens.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1) Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2) Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package at.ac.tuwien.kr.alpha.grounder.parser;
+
+import at.ac.tuwien.kr.alpha.antlr.ASPCore2Lexer;
+import at.ac.tuwien.kr.alpha.antlr.ASPCore2Parser;
+import at.ac.tuwien.kr.alpha.common.atoms.BasicAtom;
+import at.ac.tuwien.kr.alpha.common.atoms.Literal;
+import at.ac.tuwien.kr.alpha.common.terms.Term;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.ParserRuleContext;
+import org.antlr.v4.runtime.RecognitionException;
+import org.antlr.v4.runtime.misc.ParseCancellationException;
+
+import java.util.Collections;
+
+/**
+ * A parser that, in contrast to {@link ProgramParser}, does not parse full programs but only program parts like
+ * atoms, terms and such.
+ */
+public class ProgramPartParser {
+ private final ParseTreeVisitor visitor = new ParseTreeVisitor(Collections.emptyMap(), true);
+
+ public Term parseTerm(String s) {
+ final ASPCore2Parser parser = getASPCore2Parser(s);
+ return (Term)parse(parser.term());
+ }
+
+ public BasicAtom parseBasicAtom(String s) {
+ final ASPCore2Parser parser = getASPCore2Parser(s);
+ return (BasicAtom)parse(parser.classical_literal());
+ }
+
+ public Literal parseLiteral(String s) {
+ final ASPCore2Parser parser = getASPCore2Parser(s);
+ return (Literal)parse(parser.naf_literal());
+ }
+
+ private ASPCore2Parser getASPCore2Parser(String s) {
+ return new ASPCore2Parser(new CommonTokenStream(new ASPCore2Lexer(CharStreams.fromString(s))));
+ }
+
+ private Object parse(ParserRuleContext context) {
+ try {
+ return visitor.visit(context);
+ } catch (RecognitionException | ParseCancellationException e) {
+ // If there were issues parsing the given string, we
+ // throw something that suggests that the input string
+ // is malformed.
+ throw new IllegalArgumentException("Could not parse term.", e);
+ }
+ }
+}

src/test/java/at/ac/tuwien/kr/alpha/TestUtil.java

@@ -1,5 +1,5 @@
-/**
- * Copyright (c) 2019 Siemens AG
+/*
+ * Copyright (c) 2019-2020 Siemens AG
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
@@ -30,7 +30,6 @@
 import at.ac.tuwien.kr.alpha.common.Predicate;
 import at.ac.tuwien.kr.alpha.common.atoms.Atom;
 import at.ac.tuwien.kr.alpha.common.atoms.BasicAtom;
-import at.ac.tuwien.kr.alpha.common.atoms.Literal;
 import at.ac.tuwien.kr.alpha.common.terms.ConstantTerm;
 import at.ac.tuwien.kr.alpha.common.terms.Term;
 import at.ac.tuwien.kr.alpha.common.terms.VariableTerm;
@@ -65,14 +64,6 @@ public static Atom atom(String predicateName, int... termInts) {
  }
  return new BasicAtom(Predicate.getInstance(predicateName, terms.length), terms);
  }
-
- public static Literal literal(String predicateName, String... termStrings) {
- return atom(predicateName, termStrings).toLiteral();
- }
-
- public static Literal literal(String predicateName, int... termInts) {
- return atom(predicateName, termInts).toLiteral();
- }
 
  public static void printNoGoods(AtomStore atomStore, Collection<NoGood> noGoods) {
  System.out.println(noGoods.stream().map(atomStore::noGoodToString).collect(Collectors.toSet()));