Move precedence up by one to prepare for **

Author: MarcellPerger1

src/main/java/net/marcellperger/mathexpr/SymbolInfo.java

@@ -19,11 +19,11 @@
 public enum SymbolInfo {
     // Let's say that precedence 0 is for (parens) OR literals - TODO add a class?? but it wouldn't actually be used !
     // POW(PowOperation.class, 1, GroupingDirection.RightToLeft, "**"),
-    MUL(MulOperation.class, 1, GroupingDirection.LeftToRight, "*", MulOperation::new),
-    DIV(DivOperation.class, 1, GroupingDirection.LeftToRight, "/", DivOperation::new),
+    MUL(MulOperation.class, 2, GroupingDirection.LeftToRight, "*", MulOperation::new),
+    DIV(DivOperation.class, 2, GroupingDirection.LeftToRight, "/", DivOperation::new),
 
-    ADD(AddOperation.class, 2, GroupingDirection.LeftToRight, "+", AddOperation::new),
-    SUB(SubOperation.class, 2, GroupingDirection.LeftToRight, "-", SubOperation::new),
+    ADD(AddOperation.class, 3, GroupingDirection.LeftToRight, "+", AddOperation::new),
+    SUB(SubOperation.class, 3, GroupingDirection.LeftToRight, "-", SubOperation::new),
     ;
 
     public static final Map<Class<? extends MathSymbol>, SymbolInfo> CLS_TO_INFO_MAP;

src/main/java/net/marcellperger/mathexpr/parser/Parser.java

@@ -30,7 +30,7 @@ public Parser(String src_) {
     }
 
     public MathSymbol parse() throws ExprParseException {
-        MathSymbol sym = parseInfixPrecedenceLevel(2);  // TODO compute max prec level
+        MathSymbol sym = parseInfixPrecedenceLevel(3);  // TODO compute max prec level
         discardWhitespace();
         if(notEof()) throw new ExprParseException("Syntax error: didn't reach end of input");
         return sym;
@@ -69,9 +69,10 @@ public MathSymbol parse() throws ExprParseException {
         return parseDoubleLiteral_null();
     }
 
+    private static final int PREC_IN_PARENS = 3;  // TODO compute max prec level
     public @Nullable MathSymbol parseParens() throws ExprParseException {
         advanceExpectNext('(');
-        MathSymbol sym = parseInfixPrecedenceLevel(2);  // TODO use .parse() when it is completed
+        MathSymbol sym = parseInfixPrecedenceLevel(PREC_IN_PARENS);  // TODO use .parse() when it is completed
         advanceExpectNext(')');
         return sym;
     }
@@ -81,11 +82,12 @@ public MathSymbol parseInfixPrecedenceLevel(int level) throws ExprParseException
         if(level == 0) {
             return parseParensOrLiteral();
         }
-
+        // TODO remove this next-line:
+        if(SymbolInfo.PREC_TO_INFO_MAP.get(level) == null) { return parseInfixPrecedenceLevel(level - 1); }
         Set<SymbolInfo> symbols = Util.requireNonEmptyNonNull(SymbolInfo.PREC_TO_INFO_MAP.get(level));
         @Nullable GroupingDirection dirn = symbols.stream()
             .map(sm -> sm.groupingDirection).distinct().collect(UtilCollectors.singleItem());
-        assert dirn == GroupingDirection.LeftToRight: "RTL/unknown operators not implemented yet";
+        assert dirn == GroupingDirection.LeftToRight: "RTL/unknown operators not implemented yet"; // TODO
         Map<String, SymbolInfo> infixToSymbolInfo = symbols.stream().collect(  // TODO pre-compute/cache these
             Collectors.toUnmodifiableMap(
                 si -> Objects.requireNonNull(si.infix, "null infix not allowed for parseInfixPrecedenceLevel"),

src/main/java/net/marcellperger/mathexpr/util/Util.java

@@ -56,8 +56,8 @@ protected Util() {}
         return collection;
     }
     @SuppressWarnings("UnusedReturnValue")
-    @Contract("_ -> param1")
-    public static <C extends Collection<?>> @NotNull C requireNonEmptyNonNull(@NotNull C collection) {
+    @Contract("null -> fail; _ -> param1")
+    public static <C extends Collection<?>> @NotNull C requireNonEmptyNonNull(C collection) {
         Objects.requireNonNull(collection);
         // IllegalArgumentException might not always be appropriate
         if(collection.isEmpty()) throw new IllegalArgumentException("Argument must not be empty");

src/test/java/net/marcellperger/mathexpr/parser/ParserTest.java

@@ -15,6 +15,9 @@
 import static org.junit.jupiter.api.Assertions.*;
 
 class ParserTest {
+    public static final int MUL_PREC = 2;
+    public static final int ADD_PREC = 3;
+
     boolean nocache = false;
 
     void assertInfixParsesTo(String src, int level, MathSymbol expected) {
@@ -60,27 +63,27 @@ void assertInfixParsesToInner(String src, int level, MathSymbol expected) {
 
     @Test
     void parseInfixPrecedenceLevel() {
-        assertInfixParsesTo("1.0/2.0", 1,
+        assertInfixParsesTo("1.0/2.0", MUL_PREC,
             new DivOperation(new BasicDoubleSymbol(1.0), new BasicDoubleSymbol(2.0)));
-        assertInfixParsesTo(".3*6.", 1,
+        assertInfixParsesTo(".3*6.", MUL_PREC,
             new MulOperation(new BasicDoubleSymbol(.3), new BasicDoubleSymbol(6.)));
-        assertInfixParsesTo("2.1*5.3+1.1", 2,
+        assertInfixParsesTo("2.1*5.3+1.1", ADD_PREC,
             new AddOperation(new MulOperation(new BasicDoubleSymbol(2.1), new BasicDoubleSymbol(5.3)), new BasicDoubleSymbol(1.1)));
-        assertInfixParsesTo("0.9-2.1/.3", 2,
+        assertInfixParsesTo("0.9-2.1/.3", ADD_PREC,
             new SubOperation(new BasicDoubleSymbol(0.9), new DivOperation(new BasicDoubleSymbol(2.1), new BasicDoubleSymbol(.3))));
-        assertInfixParsesTo("(2.2+1.1)+3.7", 2,
+        assertInfixParsesTo("(2.2+1.1)+3.7", ADD_PREC,
             new AddOperation(new AddOperation(new BasicDoubleSymbol(2.2), new BasicDoubleSymbol(1.1)), new BasicDoubleSymbol(3.7)));
-        assertInfixParsesTo(CommonData.getBigData1_groupingParens(), 2);
-        assertInfixParsesTo(CommonData.getBigData2_groupingParens(), 2);
-        assertInfixParsesTo("2.2+1.1+3.7", 2,
+        assertInfixParsesTo(CommonData.getBigData1_groupingParens(), ADD_PREC);
+        assertInfixParsesTo(CommonData.getBigData2_groupingParens(), ADD_PREC);
+        assertInfixParsesTo("2.2+1.1+3.7", ADD_PREC,
             new AddOperation(new AddOperation(new BasicDoubleSymbol(2.2), new BasicDoubleSymbol(1.1)), new BasicDoubleSymbol(3.7)));
-        assertInfixParsesTo("2.2+1.1+3.7+0.2", 2,
+        assertInfixParsesTo("2.2+1.1+3.7+0.2", ADD_PREC,
             new AddOperation(new AddOperation(new AddOperation(new BasicDoubleSymbol(2.2), new BasicDoubleSymbol(1.1)), new BasicDoubleSymbol(3.7)), new BasicDoubleSymbol(0.2)));
-        assertInfixParsesTo(CommonData.getBigData1_minimumParens(), 2);
-        assertInfixParsesTo(CommonData.getBigData2_minimumParens(), 2);
-        assertInfixParsesTo(".9/2./3.3", 1,
+        assertInfixParsesTo(CommonData.getBigData1_minimumParens(), ADD_PREC);
+        assertInfixParsesTo(CommonData.getBigData2_minimumParens(), ADD_PREC);
+        assertInfixParsesTo(".9/2./3.3", MUL_PREC,
             new DivOperation(new DivOperation(new BasicDoubleSymbol(.9), new BasicDoubleSymbol(2.)), new BasicDoubleSymbol(3.3)));
-        assertInfixParsesTo(".9/2./3.3", 2,
+        assertInfixParsesTo(".9/2./3.3", ADD_PREC,
             new DivOperation(new DivOperation(new BasicDoubleSymbol(.9), new BasicDoubleSymbol(2.)), new BasicDoubleSymbol(3.3)));
     }