PoC JavaCC parser

src/main/java/com/booleworks/logicng/io/parsers/PropositionalParserNew.java

@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: Apache-2.0 and MIT
+// Copyright 2015-2023 Christoph Zengler
+// Copyright 2023-20xx BooleWorks GmbH
+
+package com.booleworks.logicng.io.parsers;
+
+import com.booleworks.logicng.formulas.Formula;
+import com.booleworks.logicng.formulas.FormulaFactory;
+import com.booleworks.logicng.io.parsers.javacc.BooleanFormulaParser;
+import com.booleworks.logicng.io.parsers.javacc.ParseException;
+import com.booleworks.logicng.io.parsers.javacc.TokenMgrError;
+
+import java.io.StringReader;
+
+/**
+ * A parser for propositional (including pseudo-Boolean) formulas.
+ * <p>
+ * The syntax for pseudo Boolean formulas in LogicNG is:
+ * <ul>
+ * <li>{@code $true} for the constant TRUE</li>
+ * <li>{@code $false} for the constant FALSE</li>
+ * <li>{@code ~} for the negation</li>
+ * <li>{@code |} for the disjunction (OR)</li>
+ * <li>{@code &} for the conjunction (AND)</li>
+ * <li>{@code =>} for the implication</li>
+ * <li>{@code <=>} for the equivalence</li>
+ * <li>{@code *} for the multiplication of a literal and its coefficient</li>
+ * <li>{@code +} for the summation</li>
+ * <li>{@code =} for equals</li>
+ * <li>{@code <=} for less-equals</li>
+ * <li>{@code <} for less than</li>
+ * <li>{@code >=} for greater-equals</li>
+ * <li>{@code >} for greater than</li>
+ * </ul>
+ * Brackets are {@code (} and {@code )}. For variable names, there are the
+ * following rules:
+ * <ul>
+ * <li>must begin with a alphabetic character, {@code _}, {@code @}, or
+ * {@code #}</li>
+ * <li>can only contain alphanumerical character, {@code _}, or {@code #}</li>
+ * <li>{@code @} is only allowed at the beginning of the variable name and is
+ * reserved for special internal variables</li>
+ * </ul>
+ * <p>
+ * A valid pseudo Boolean expression is of the form
+ * {@code c_1 * l_1 + ... + c_n * l_n R k} where the {@code c_i} are
+ * coefficients, {@code l_i} are literals, and {@code R} is one of
+ * {@code =, >, >=, <, <=}.
+ * @version 2.4.1
+ * @since 1.0
+ */
+public final class PropositionalParserNew {
+
+    private final BooleanFormulaParser parser;
+
+    /**
+     * Constructs a new parser for pseudo boolean formulas.
+     * @param f the formula factory
+     */
+    public PropositionalParserNew(final FormulaFactory f) {
+        parser = new BooleanFormulaParser(new StringReader(""));
+        parser.setFactory(f);
+    }
+
+    public Formula parse(final String input) throws ParserException {
+        if (input == null || input.isBlank()) {
+            return parser.getFactory().verum();
+        }
+        try {
+            parser.ReInit(new StringReader(input));
+            return parser.formula();
+        } catch (final TokenMgrError e) {
+            throw new ParserException("lexer error", null); //TODO
+        } catch (final ParseException e) {
+            throw new ParserException("parser error", e); //TODO
+        }
+    }
+
+    public FormulaFactory factory() {
+        return parser.getFactory();
+    }
+}