Tidy up some code

Author: MarcellPerger1

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

@@ -18,7 +18,7 @@
 
 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, "**"),  // TODO PowOperation::new
+    POW(PowOperation.class, 1, GroupingDirection.RightToLeft, "**", PowOperation::new),
     MUL(MulOperation.class, 2, GroupingDirection.LeftToRight, "*", MulOperation::new),
     DIV(DivOperation.class, 2, GroupingDirection.LeftToRight, "/", DivOperation::new),
 

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

@@ -85,8 +85,6 @@ public MathSymbol parseInfixPrecedenceLevel(int level) throws ExprParseException
         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());
-        // if(dirn != GroupingDirection.LeftToRight) { return parseInfixPrecedenceLevel(level - 1); }  // TODO TDD: remove
-        // 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"),