Release version 0.5.0 (merge into stable)

8 files changed, 453 insertions, 299 deletions

diff --git a/src/main/java/sevenUnits/utils/ConditionalExistenceCollections.java b/src/main/java/sevenUnits/utils/ConditionalExistenceCollections.java
index bee4dd1..b71a4e0 100644
--- a/src/main/java/sevenUnits/utils/ConditionalExistenceCollections.java
+++ b/src/main/java/sevenUnits/utils/ConditionalExistenceCollections.java
@@ -67,7 +67,7 @@ public final class ConditionalExistenceCollections {
 			extends AbstractCollection<E> {
 		final Collection<E> collection;
 		final Predicate<E> existenceCondition;
-		
+
 		/**
 		 * Creates the {@code ConditionalExistenceCollection}.
 		 * 
@@ -80,38 +80,38 @@ public final class ConditionalExistenceCollections {
 			this.collection = collection;
 			this.existenceCondition = existenceCondition;
 		}
-		
+
 		@Override
 		public boolean add(final E e) {
 			return this.collection.add(e) && this.existenceCondition.test(e);
 		}
-		
+
 		@Override
 		public void clear() {
 			this.collection.clear();
 		}
-		
+
 		@Override
 		public boolean contains(final Object o) {
 			if (!this.collection.contains(o))
 				return false;
-				
+
 			// this collection can only contain instances of E
 			// since the object is in the collection, we know that it must be an
 			// instance of E
 			// therefore this cast will always work
 			@SuppressWarnings("unchecked")
 			final E e = (E) o;
-			
+
 			return this.existenceCondition.test(e);
 		}
-		
+
 		@Override
 		public Iterator<E> iterator() {
 			return conditionalExistenceIterator(this.collection.iterator(),
 					this.existenceCondition);
 		}
-		
+
 		@Override
 		public boolean remove(final Object o) {
 			// remove() must be first in the && statement, otherwise it may not
@@ -119,32 +119,32 @@ public final class ConditionalExistenceCollections {
 			final boolean containedObject = this.contains(o);
 			return this.collection.remove(o) && containedObject;
 		}
-		
+
 		@Override
 		public int size() {
 			return (int) this.collection.stream().filter(this.existenceCondition)
 					.count();
 		}
-		
+
 		@Override
 		public Object[] toArray() {
 			// ensure the toArray operation is supported
 			this.collection.toArray();
-			
+
 			// if it works, do it for real
 			return super.toArray();
 		}
-		
+
 		@Override
 		public <T> T[] toArray(T[] a) {
 			// ensure the toArray operation is supported
 			this.collection.toArray();
-			
+
 			// if it works, do it for real
 			return super.toArray(a);
 		}
 	}
-	
+
 	/**
 	 * Elements in this wrapper iterator only exist if they pass a condition.
 	 * 
@@ -157,7 +157,7 @@ public final class ConditionalExistenceCollections {
 		final Predicate<E> existenceCondition;
 		E nextElement;
 		boolean hasNext;
-		
+
 		/**
 		 * Creates the {@code ConditionalExistenceIterator}.
 		 * 
@@ -171,7 +171,7 @@ public final class ConditionalExistenceCollections {
 			this.existenceCondition = condition;
 			this.getAndSetNextElement();
 		}
-		
+
 		/**
 		 * Gets the next element, and sets nextElement and hasNext accordingly.
 		 * 
@@ -188,12 +188,12 @@ public final class ConditionalExistenceCollections {
 			} while (!this.existenceCondition.test(this.nextElement));
 			this.hasNext = true;
 		}
-		
+
 		@Override
 		public boolean hasNext() {
 			return this.hasNext;
 		}
-		
+
 		@Override
 		public E next() {
 			if (this.hasNext()) {
@@ -203,13 +203,13 @@ public final class ConditionalExistenceCollections {
 			} else
 				throw new NoSuchElementException();
 		}
-		
+
 		@Override
 		public void remove() {
 			this.iterator.remove();
 		}
 	}
-	
+
 	/**
 	 * Mappings in this map only exist if the entry passes some condition.
 	 * 
@@ -221,7 +221,7 @@ public final class ConditionalExistenceCollections {
 	static final class ConditionalExistenceMap<K, V> extends AbstractMap<K, V> {
 		Map<K, V> map;
 		Predicate<Entry<K, V>> entryExistenceCondition;
-		
+
 		/**
 		 * Creates the {@code ConditionalExistenceMap}.
 		 * 
@@ -234,81 +234,81 @@ public final class ConditionalExistenceCollections {
 			this.map = map;
 			this.entryExistenceCondition = entryExistenceCondition;
 		}
-		
+
 		@Override
 		public boolean containsKey(final Object key) {
 			if (!this.map.containsKey(key))
 				return false;
-				
+
 			// only instances of K have mappings in the backing map
 			// since we know that key is a valid key, it must be an instance of K
 			@SuppressWarnings("unchecked")
 			final K keyAsK = (K) key;
-			
+
 			// get and test entry
 			final V value = this.map.get(key);
 			final Entry<K, V> entry = new SimpleEntry<>(keyAsK, value);
 			return this.entryExistenceCondition.test(entry);
 		}
-		
+
 		@Override
 		public Set<Entry<K, V>> entrySet() {
 			return conditionalExistenceSet(this.map.entrySet(),
 					this.entryExistenceCondition);
 		}
-		
+
 		@Override
 		public V get(final Object key) {
 			return this.containsKey(key) ? this.map.get(key) : null;
 		}
-		
+
 		private final Entry<K, V> getEntry(K key) {
 			return new Entry<>() {
 				@Override
 				public K getKey() {
 					return key;
 				}
-				
+
 				@Override
 				public V getValue() {
 					return ConditionalExistenceMap.this.map.get(key);
 				}
-				
+
 				@Override
 				public V setValue(V value) {
 					return ConditionalExistenceMap.this.map.put(key, value);
 				}
 			};
 		}
-		
+
 		@Override
 		public Set<K> keySet() {
 			return conditionalExistenceSet(this.map.keySet(),
 					k -> this.entryExistenceCondition.test(this.getEntry(k)));
 		}
-		
+
 		@Override
 		public V put(final K key, final V value) {
 			final V oldValue = this.map.put(key, value);
-			
+
 			// get and test entry
 			final Entry<K, V> entry = new SimpleEntry<>(key, oldValue);
 			return this.entryExistenceCondition.test(entry) ? oldValue : null;
 		}
-		
+
 		@Override
 		public V remove(final Object key) {
 			final V oldValue = this.map.remove(key);
 			return this.containsKey(key) ? oldValue : null;
 		}
-		
+
 		@Override
 		public Collection<V> values() {
 			// maybe change this to use ConditionalExistenceCollection
 			return super.values();
 		}
 	}
-	
+
 	/**
 	 * Elements in this set only exist if a certain condition is true.
 	 * 
@@ -319,7 +319,7 @@ public final class ConditionalExistenceCollections {
 	static final class ConditionalExistenceSet<E> extends AbstractSet<E> {
 		private final Set<E> set;
 		private final Predicate<E> existenceCondition;
-		
+
 		/**
 		 * Creates the {@code ConditionalNonexistenceSet}.
 		 * 
@@ -332,7 +332,7 @@ public final class ConditionalExistenceCollections {
 			this.set = set;
 			this.existenceCondition = existenceCondition;
 		}
-		
+
 		/**
 		 * {@inheritDoc}
 		 * <p>
@@ -343,33 +343,33 @@ public final class ConditionalExistenceCollections {
 		public boolean add(final E e) {
 			return this.set.add(e) && this.existenceCondition.test(e);
 		}
-		
+
 		@Override
 		public void clear() {
 			this.set.clear();
 		}
-		
+
 		@Override
 		public boolean contains(final Object o) {
 			if (!this.set.contains(o))
 				return false;
-				
+
 			// this set can only contain instances of E
 			// since the object is in the set, we know that it must be an instance
 			// of E
 			// therefore this cast will always work
 			@SuppressWarnings("unchecked")
 			final E e = (E) o;
-			
+
 			return this.existenceCondition.test(e);
 		}
-		
+
 		@Override
 		public Iterator<E> iterator() {
 			return conditionalExistenceIterator(this.set.iterator(),
 					this.existenceCondition);
 		}
-		
+
 		@Override
 		public boolean remove(final Object o) {
 			// remove() must be first in the && statement, otherwise it may not
@@ -377,31 +377,31 @@ public final class ConditionalExistenceCollections {
 			final boolean containedObject = this.contains(o);
 			return this.set.remove(o) && containedObject;
 		}
-		
+
 		@Override
 		public int size() {
 			return (int) this.set.stream().filter(this.existenceCondition).count();
 		}
-		
+
 		@Override
 		public Object[] toArray() {
 			// ensure the toArray operation is supported
 			this.set.toArray();
-			
+
 			// if it works, do it for real
 			return super.toArray();
 		}
-		
+
 		@Override
 		public <T> T[] toArray(T[] a) {
 			// ensure the toArray operation is supported
 			this.set.toArray();
-			
+
 			// if it works, do it for real
 			return super.toArray(a);
 		}
 	}
-	
+
 	/**
 	 * Elements in the returned wrapper collection are ignored if they don't pass
 	 * a condition.
@@ -418,7 +418,7 @@ public final class ConditionalExistenceCollections {
 		return new ConditionalExistenceCollection<>(collection,
 				existenceCondition);
 	}
-	
+
 	/**
 	 * Elements in the returned wrapper iterator are ignored if they don't pass a
 	 * condition.
@@ -433,7 +433,7 @@ public final class ConditionalExistenceCollections {
 			final Iterator<E> iterator, final Predicate<E> existenceCondition) {
 		return new ConditionalExistenceIterator<>(iterator, existenceCondition);
 	}
-	
+
 	/**
 	 * Mappings in the returned wrapper map are ignored if the corresponding
 	 * entry doesn't pass a condition
@@ -450,7 +450,7 @@ public final class ConditionalExistenceCollections {
 			final Predicate<Entry<K, V>> entryExistenceCondition) {
 		return new ConditionalExistenceMap<>(map, entryExistenceCondition);
 	}
-	
+
 	/**
 	 * Elements in the returned wrapper set are ignored if they don't pass a
 	 * condition.
diff --git a/src/main/java/sevenUnits/utils/DecimalComparison.java b/src/main/java/sevenUnits/utils/DecimalComparison.java
index a5cbbaa..0515b6b 100644
--- a/src/main/java/sevenUnits/utils/DecimalComparison.java
+++ b/src/main/java/sevenUnits/utils/DecimalComparison.java
@@ -34,7 +34,7 @@ public final class DecimalComparison {
 	 * @since v0.2.0
 	 */
 	public static final double DOUBLE_EPSILON = 1.0e-15;
-	
+
 	/**
 	 * The value used for float comparison. If two float values are within this
 	 * value multiplied by the larger value, they are considered equal.
@@ -43,7 +43,7 @@ public final class DecimalComparison {
 	 * @since v0.2.0
 	 */
 	public static final float FLOAT_EPSILON = 1.0e-6f;
-	
+
 	/**
 	 * Tests for equality of double values using {@link #DOUBLE_EPSILON}.
 	 * <p>
@@ -74,7 +74,7 @@ public final class DecimalComparison {
 	public static final boolean equals(final double a, final double b) {
 		return DecimalComparison.equals(a, b, DOUBLE_EPSILON);
 	}
-	
+
 	/**
 	 * Tests for double equality using a custom epsilon value.
 	 * 
@@ -106,7 +106,7 @@ public final class DecimalComparison {
 			final double epsilon) {
 		return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
 	}
-	
+
 	/**
 	 * Tests for equality of float values using {@link #FLOAT_EPSILON}.
 	 * 
@@ -136,7 +136,7 @@ public final class DecimalComparison {
 	public static final boolean equals(final float a, final float b) {
 		return DecimalComparison.equals(a, b, FLOAT_EPSILON);
 	}
-	
+
 	/**
 	 * Tests for float equality using a custom epsilon value.
 	 * 
@@ -168,7 +168,7 @@ public final class DecimalComparison {
 			final float epsilon) {
 		return Math.abs(a - b) <= epsilon * Math.max(Math.abs(a), Math.abs(b));
 	}
-	
+
 	/**
 	 * Tests for equality of {@code UncertainDouble} values using
 	 * {@link #DOUBLE_EPSILON}.
@@ -201,7 +201,7 @@ public final class DecimalComparison {
 		return DecimalComparison.equals(a.value(), b.value())
 				&& DecimalComparison.equals(a.uncertainty(), b.uncertainty());
 	}
-	
+
 	/**
 	 * Tests for {@code UncertainDouble} equality using a custom epsilon value.
 	 * 
@@ -235,7 +235,7 @@ public final class DecimalComparison {
 				&& DecimalComparison.equals(a.uncertainty(), b.uncertainty(),
 						epsilon);
 	}
-	
+
 	/**
 	 * Takes the hash code of doubles. Values that are equal according to
 	 * {@link #equals(double, double)} will have the same hash code.
@@ -247,10 +247,10 @@ public final class DecimalComparison {
 	public static final int hash(final double d) {
 		return Float.hashCode((float) d);
 	}
-	
+
 	// You may NOT get any DecimalComparison instances
 	private DecimalComparison() {
 		throw new AssertionError();
 	}
-	
+
 }
diff --git a/src/main/java/sevenUnits/utils/ExpressionParser.java b/src/main/java/sevenUnits/utils/ExpressionParser.java
index 941c2a4..e248ff0 100644
--- a/src/main/java/sevenUnits/utils/ExpressionParser.java
+++ b/src/main/java/sevenUnits/utils/ExpressionParser.java
@@ -1,5 +1,5 @@
 /**
- * Copyright (C) 2019 Adrien Hopkins
+ * Copyright (C) 2019, 2024 Adrien Hopkins
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
@@ -24,6 +24,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.function.BiFunction;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
 import java.util.function.UnaryOperator;
@@ -55,7 +56,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final Function<String, ? extends T> objectObtainer;
-		
+
 		/**
 		 * The function of the space as an operator (like 3 x y)
 		 * 
@@ -63,7 +64,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private String spaceFunction = null;
-		
+
 		/**
 		 * A map mapping operator strings to operator functions, for unary
 		 * operators.
@@ -72,7 +73,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final Map<String, PriorityUnaryOperator<T>> unaryOperators;
-		
+
 		/**
 		 * A map mapping operator strings to operator functions, for binary
 		 * operators.
@@ -81,7 +82,14 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-		
+
+		/**
+		 * A map mapping operator strings to numeric functions.
+		 * 
+		 * @since 2024-03-23
+		 */
+		private final Map<String, PriorityBiFunction<T, UncertainDouble, T>> numericOperators;
+
 		/**
 		 * Creates the {@code Builder}.
 		 * 
@@ -96,8 +104,9 @@ public final class ExpressionParser<T> {
 					"objectObtainer must not be null.");
 			this.unaryOperators = new HashMap<>();
 			this.binaryOperators = new HashMap<>();
+			this.numericOperators = new HashMap<>();
 		}
-		
+
 		/**
 		 * Adds a binary operator to the builder.
 		 * 
@@ -115,7 +124,7 @@ public final class ExpressionParser<T> {
 				final BinaryOperator<T> operator, final int priority) {
 			Objects.requireNonNull(text, "text must not be null.");
 			Objects.requireNonNull(operator, "operator must not be null.");
-			
+
 			// Unfortunately, I cannot use a lambda because the
 			// PriorityBinaryOperator requires arguments.
 			final PriorityBinaryOperator<T> priorityOperator = new PriorityBinaryOperator<>(
@@ -124,12 +133,42 @@ public final class ExpressionParser<T> {
 				public T apply(final T t, final T u) {
 					return operator.apply(t, u);
 				}
-				
+
 			};
 			this.binaryOperators.put(text, priorityOperator);
 			return this;
 		}
-		
+
+		/**
+		 * Adds a two-argument operator where the second operator is a number.
+		 * This is used for operations like vector scaling and exponentation.
+		 * 
+		 * @param text     text used to reference the operator, like '^'
+		 * @param operator operator to add
+		 * @param priority operator's priority, which determines which operators
+		 *                 are applied first
+		 * @return this builder
+		 */
+		public Builder<T> addNumericOperator(final String text,
+				final BiFunction<T, UncertainDouble, T> operator,
+				final int priority) {
+			Objects.requireNonNull(text, "text must not be null.");
+			Objects.requireNonNull(operator, "operator must not be null.");
+
+			// Unfortunately, I cannot use a lambda because the
+			// PriorityBinaryOperator requires arguments.
+			final PriorityBiFunction<T, UncertainDouble, T> priorityOperator = new PriorityBiFunction<>(
+					priority) {
+				@Override
+				public T apply(final T t, final UncertainDouble u) {
+					return operator.apply(t, u);
+				}
+
+			};
+			this.numericOperators.put(text, priorityOperator);
+			return this;
+		}
+
 		/**
 		 * Adds a function for spaces. You must use the text of an existing binary
 		 * operator.
@@ -141,15 +180,15 @@ public final class ExpressionParser<T> {
 		 */
 		public Builder<T> addSpaceFunction(final String operator) {
 			Objects.requireNonNull(operator, "operator must not be null.");
-			
+
 			if (!this.binaryOperators.containsKey(operator))
 				throw new IllegalArgumentException(String
 						.format("Could not find binary operator '%s'", operator));
-			
+
 			this.spaceFunction = operator;
 			return this;
 		}
-		
+
 		/**
 		 * Adds a unary operator to the builder.
 		 * 
@@ -167,7 +206,7 @@ public final class ExpressionParser<T> {
 				final UnaryOperator<T> operator, final int priority) {
 			Objects.requireNonNull(text, "text must not be null.");
 			Objects.requireNonNull(operator, "operator must not be null.");
-			
+
 			// Unfortunately, I cannot use a lambda because the
 			// PriorityUnaryOperator requires arguments.
 			final PriorityUnaryOperator<T> priorityOperator = new PriorityUnaryOperator<>(
@@ -180,7 +219,7 @@ public final class ExpressionParser<T> {
 			this.unaryOperators.put(text, priorityOperator);
 			return this;
 		}
-		
+
 		/**
 		 * @return an {@code ExpressionParser<T>} instance with the properties
 		 *         given to this builder
@@ -189,10 +228,10 @@ public final class ExpressionParser<T> {
 		 */
 		public ExpressionParser<T> build() {
 			return new ExpressionParser<>(this.objectObtainer, this.unaryOperators,
-					this.binaryOperators, this.spaceFunction);
+					this.binaryOperators, this.numericOperators, this.spaceFunction);
 		}
 	}
-	
+
 	/**
 	 * A binary operator with a priority field that determines which operators
 	 * apply first.
@@ -212,7 +251,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final int priority;
-		
+
 		/**
 		 * Creates the {@code PriorityBinaryOperator}.
 		 * 
@@ -223,7 +262,7 @@ public final class ExpressionParser<T> {
 		public PriorityBinaryOperator(final int priority) {
 			this.priority = priority;
 		}
-		
+
 		/**
 		 * Compares this object to another by priority.
 		 * 
@@ -243,7 +282,68 @@ public final class ExpressionParser<T> {
 			else
 				return 0;
 		}
-		
+
+		/**
+		 * @return priority
+		 * @since 2019-03-22
+		 * @since v0.2.0
+		 */
+		public final int getPriority() {
+			return this.priority;
+		}
+	}
+
+	/**
+	 * A binary operator with a priority field that determines which operators
+	 * apply first.
+	 * 
+	 * @author Adrien Hopkins
+	 * @param <T> type of operand and result
+	 * @since 2019-03-17
+	 * @since v0.2.0
+	 */
+	private static abstract class PriorityBiFunction<T, U, R> implements
+			BiFunction<T, U, R>, Comparable<PriorityBiFunction<T, U, R>> {
+		/**
+		 * The operator's priority. Higher-priority operators are applied before
+		 * lower-priority operators
+		 * 
+		 * @since 2019-03-17
+		 * @since v0.2.0
+		 */
+		private final int priority;
+
+		/**
+		 * Creates the {@code PriorityBinaryOperator}.
+		 * 
+		 * @param priority operator's priority
+		 * @since 2019-03-17
+		 * @since v0.2.0
+		 */
+		public PriorityBiFunction(final int priority) {
+			this.priority = priority;
+		}
+
+		/**
+		 * Compares this object to another by priority.
+		 * 
+		 * <p>
+		 * {@inheritDoc}
+		 * </p>
+		 * 
+		 * @since 2019-03-17
+		 * @since v0.2.0
+		 */
+		@Override
+		public int compareTo(final PriorityBiFunction<T, U, R> o) {
+			if (this.priority < o.priority)
+				return -1;
+			else if (this.priority > o.priority)
+				return 1;
+			else
+				return 0;
+		}
+
 		/**
 		 * @return priority
 		 * @since 2019-03-22
@@ -253,7 +353,7 @@ public final class ExpressionParser<T> {
 			return this.priority;
 		}
 	}
-	
+
 	/**
 	 * A unary operator with a priority field that determines which operators
 	 * apply first.
@@ -273,7 +373,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final int priority;
-		
+
 		/**
 		 * Creates the {@code PriorityUnaryOperator}.
 		 * 
@@ -284,7 +384,7 @@ public final class ExpressionParser<T> {
 		public PriorityUnaryOperator(final int priority) {
 			this.priority = priority;
 		}
-		
+
 		/**
 		 * Compares this object to another by priority.
 		 * 
@@ -304,7 +404,7 @@ public final class ExpressionParser<T> {
 			else
 				return 0;
 		}
-		
+
 		/**
 		 * @return priority
 		 * @since 2019-03-22
@@ -314,7 +414,7 @@ public final class ExpressionParser<T> {
 			return this.priority;
 		}
 	}
-	
+
 	/**
 	 * The types of tokens that are available.
 	 * 
@@ -323,9 +423,9 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private static enum TokenType {
-		OBJECT, UNARY_OPERATOR, BINARY_OPERATOR;
+		OBJECT, UNARY_OPERATOR, BINARY_OPERATOR, NUMERIC_OPERATOR;
 	}
-	
+
 	/**
 	 * The opening bracket.
 	 * 
@@ -333,7 +433,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	public static final char OPENING_BRACKET = '(';
-	
+
 	/**
 	 * The closing bracket.
 	 * 
@@ -341,7 +441,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	public static final char CLOSING_BRACKET = ')';
-	
+
 	/**
 	 * Finds the other bracket in a pair of brackets, given the position of one.
 	 * 
@@ -355,9 +455,9 @@ public final class ExpressionParser<T> {
 	private static int findBracketPair(final String string,
 			final int bracketPosition) {
 		Objects.requireNonNull(string, "string must not be null.");
-		
+
 		final char openingBracket = string.charAt(bracketPosition);
-		
+
 		// figure out what closing bracket to look for
 		final char closingBracket;
 		switch (openingBracket) {
@@ -374,16 +474,16 @@ public final class ExpressionParser<T> {
 			throw new IllegalArgumentException(
 					String.format("Invalid bracket '%s'", openingBracket));
 		}
-		
+
 		// level of brackets. every opening bracket increments this; every closing
 		// bracket decrements it
 		int bracketLevel = 0;
-		
+
 		// iterate over the string to find the closing bracket
 		for (int currentPosition = bracketPosition; currentPosition < string
 				.length(); currentPosition++) {
 			final char currentCharacter = string.charAt(currentPosition);
-			
+
 			if (currentCharacter == openingBracket) {
 				bracketLevel++;
 			} else if (currentCharacter == closingBracket) {
@@ -392,10 +492,10 @@ public final class ExpressionParser<T> {
 					return currentPosition;
 			}
 		}
-		
+
 		throw new IllegalArgumentException("No matching bracket found.");
 	}
-	
+
 	/**
 	 * A function that obtains a parseable object from a string. For example, an
 	 * integer {@code ExpressionParser} would use {@code Integer::parseInt}.
@@ -404,7 +504,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final Function<String, ? extends T> objectObtainer;
-	
+
 	/**
 	 * A map mapping operator strings to operator functions, for unary operators.
 	 * 
@@ -412,7 +512,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final Map<String, PriorityUnaryOperator<T>> unaryOperators;
-	
+
 	/**
 	 * A map mapping operator strings to operator functions, for binary
 	 * operators.
@@ -421,7 +521,14 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-	
+
+	/**
+	 * A map mapping operator strings to numeric functions.
+	 * 
+	 * @since 2024-03-23
+	 */
+	private final Map<String, PriorityBiFunction<T, UncertainDouble, T>> numericOperators;
+
 	/**
 	 * The operator for space, or null if spaces have no function.
 	 * 
@@ -429,27 +536,30 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final String spaceOperator;
-	
+
 	/**
 	 * Creates the {@code ExpressionParser}.
 	 * 
-	 * @param objectObtainer  function to get objects from strings
-	 * @param unaryOperators  unary operators available to the parser
-	 * @param binaryOperators binary operators available to the parser
-	 * @param spaceOperator   operator used by spaces
+	 * @param objectObtainer   function to get objects from strings
+	 * @param unaryOperators   unary operators available to the parser
+	 * @param binaryOperators  binary operators available to the parser
+	 * @param numericOperators numeric operators available to the parser
+	 * @param spaceOperator    operator used by spaces
 	 * @since 2019-03-14
 	 * @since v0.2.0
 	 */
 	private ExpressionParser(final Function<String, ? extends T> objectObtainer,
 			final Map<String, PriorityUnaryOperator<T>> unaryOperators,
 			final Map<String, PriorityBinaryOperator<T>> binaryOperators,
+			final Map<String, PriorityBiFunction<T, UncertainDouble, T>> numericOperators,
 			final String spaceOperator) {
 		this.objectObtainer = objectObtainer;
 		this.unaryOperators = unaryOperators;
 		this.binaryOperators = binaryOperators;
+		this.numericOperators = numericOperators;
 		this.spaceOperator = spaceOperator;
 	}
-	
+
 	/**
 	 * Converts a given mathematical expression to reverse Polish notation
 	 * (operators after operands).
@@ -468,19 +578,19 @@ public final class ExpressionParser<T> {
 	 */
 	String convertExpressionToReversePolish(final String expression) {
 		Objects.requireNonNull(expression, "expression must not be null.");
-		
+
 		final List<String> components = new ArrayList<>();
-		
+
 		// the part of the expression remaining to parse
 		String partialExpression = expression;
-		
+
 		// find and deal with brackets
 		while (partialExpression.indexOf(OPENING_BRACKET) != -1) {
 			final int openingBracketPosition = partialExpression
 					.indexOf(OPENING_BRACKET);
 			final int closingBracketPosition = findBracketPair(partialExpression,
 					openingBracketPosition);
-			
+
 			// check for function
 			if (openingBracketPosition > 0
 					&& partialExpression.charAt(openingBracketPosition - 1) != ' ') {
@@ -510,15 +620,15 @@ public final class ExpressionParser<T> {
 						.substring(closingBracketPosition + 1);
 			}
 		}
-		
+
 		// add everything else
 		components.addAll(Arrays.asList(partialExpression.split(" ")));
-		
+
 		// remove empty entries
 		while (components.contains("")) {
 			components.remove("");
 		}
-		
+
 		// deal with space multiplication (x y)
 		if (this.spaceOperator != null) {
 			for (int i = 0; i < components.size() - 1; i++) {
@@ -528,7 +638,7 @@ public final class ExpressionParser<T> {
 				}
 			}
 		}
-		
+
 		// turn the expression into reverse Polish
 		while (true) {
 			final int highestPriorityOperatorPosition = this
@@ -536,7 +646,7 @@ public final class ExpressionParser<T> {
 			if (highestPriorityOperatorPosition == -1) {
 				break;
 			}
-			
+
 			// swap components based on what kind of operator there is
 			// 1 + 2 becomes 2 1 +
 			// - 1 becomes 1 -
@@ -554,6 +664,7 @@ public final class ExpressionParser<T> {
 						operand + " " + unaryOperator);
 				break;
 			case BINARY_OPERATOR:
+			case NUMERIC_OPERATOR:
 				if (components.size() < 3)
 					throw new IllegalArgumentException(
 							"Invalid expression \"" + expression + "\"");
@@ -570,11 +681,11 @@ public final class ExpressionParser<T> {
 				throw new AssertionError("Expected operator, found non-operator.");
 			}
 		}
-		
+
 		// join all of the components together, then ensure there is only one
 		// space in a row
 		String expressionRPN = String.join(" ", components).replaceAll(" +", " ");
-		
+
 		while (expressionRPN.charAt(0) == ' ') {
 			expressionRPN = expressionRPN.substring(1);
 		}
@@ -583,7 +694,7 @@ public final class ExpressionParser<T> {
 		}
 		return expressionRPN;
 	}
-	
+
 	/**
 	 * Finds the position of the highest-priority operator in a list
 	 * 
@@ -601,18 +712,18 @@ public final class ExpressionParser<T> {
 		// find highest priority
 		int maxPriority = Integer.MIN_VALUE;
 		int maxPriorityPosition = -1;
-		
+
 		// go over components one by one
 		// if it is an operator, test its priority to see if it's max
 		// if it is, update maxPriority and maxPriorityPosition
 		for (int i = 0; i < components.size(); i++) {
-			
+
 			switch (this.getTokenType(components.get(i))) {
 			case UNARY_OPERATOR:
 				final PriorityUnaryOperator<T> unaryOperator = this.unaryOperators
 						.get(components.get(i));
 				final int unaryPriority = unaryOperator.getPriority();
-				
+
 				if (unaryPriority > maxPriority) {
 					maxPriority = unaryPriority;
 					maxPriorityPosition = i;
@@ -622,21 +733,31 @@ public final class ExpressionParser<T> {
 				final PriorityBinaryOperator<T> binaryOperator = this.binaryOperators
 						.get(components.get(i));
 				final int binaryPriority = binaryOperator.getPriority();
-				
+
 				if (binaryPriority > maxPriority) {
 					maxPriority = binaryPriority;
 					maxPriorityPosition = i;
 				}
 				break;
+			case NUMERIC_OPERATOR:
+				final PriorityBiFunction<T, UncertainDouble, T> numericOperator = this.numericOperators
+						.get(components.get(i));
+				final int numericPriority = numericOperator.getPriority();
+
+				if (numericPriority > maxPriority) {
+					maxPriority = numericPriority;
+					maxPriorityPosition = i;
+				}
+				break;
 			default:
 				break;
 			}
 		}
-		
+
 		// max priority position found
 		return maxPriorityPosition;
 	}
-	
+
 	/**
 	 * Determines whether an inputted string is an object or an operator
 	 * 
@@ -648,15 +769,17 @@ public final class ExpressionParser<T> {
 	 */
 	private TokenType getTokenType(final String token) {
 		Objects.requireNonNull(token, "token must not be null.");
-		
+
 		if (this.unaryOperators.containsKey(token))
 			return TokenType.UNARY_OPERATOR;
 		else if (this.binaryOperators.containsKey(token))
 			return TokenType.BINARY_OPERATOR;
+		else if (this.numericOperators.containsKey(token))
+			return TokenType.NUMERIC_OPERATOR;
 		else
 			return TokenType.OBJECT;
 	}
-	
+
 	/**
 	 * Parses an expression.
 	 * 
@@ -670,7 +793,7 @@ public final class ExpressionParser<T> {
 		return this.parseReversePolishExpression(
 				this.convertExpressionToReversePolish(expression));
 	}
-	
+
 	/**
 	 * Parses an expression expressed in reverse Polish notation.
 	 * 
@@ -682,55 +805,86 @@ public final class ExpressionParser<T> {
 	 */
 	T parseReversePolishExpression(final String expression) {
 		Objects.requireNonNull(expression, "expression must not be null.");
-		
+
 		final Deque<T> stack = new ArrayDeque<>();
-		
+		final Deque<UncertainDouble> doubleStack = new ArrayDeque<>();
+
 		// iterate over every item in the expression, then
 		for (final String item : expression.split(" ")) {
 			// choose a path based on what kind of thing was just read
 			switch (this.getTokenType(item)) {
-			
+
 			case BINARY_OPERATOR:
 				if (stack.size() < 2)
 					throw new IllegalStateException(String.format(
 							"Attempted to call binary operator %s with only %d arguments.",
 							item, stack.size()));
-				
+
 				// get two arguments and operator, then apply!
 				final T o1 = stack.pop();
 				final T o2 = stack.pop();
 				final BinaryOperator<T> binaryOperator = this.binaryOperators
 						.get(item);
-				
+
 				stack.push(binaryOperator.apply(o1, o2));
 				break;
-			
+
+			case NUMERIC_OPERATOR:
+				if (stack.size() < 1 || doubleStack.size() < 1)
+					throw new IllegalStateException(String.format(
+							"Attempted to call binary operator %s with insufficient arguments.",
+							item));
+
+				final T ot = stack.pop();
+				final UncertainDouble on = doubleStack.pop();
+				final BiFunction<T, UncertainDouble, T> op = this.numericOperators
+						.get(item);
+				stack.push(op.apply(ot, on));
+				break;
+
 			case OBJECT:
 				// just add it to the stack
-				stack.push(this.objectObtainer.apply(item));
+				// these try-catch statements are necessary
+				// to make the code as generalizable as possible
+				// also they're required for number formatting code because
+				// that's the only way to tell if an expression is a number or not.
+				try {
+					stack.push(this.objectObtainer.apply(item));
+				} catch (Exception e) {
+					try {
+						doubleStack.push(UncertainDouble.fromString(item));
+					} catch (IllegalArgumentException e2) {
+						try {
+							doubleStack.push(
+									UncertainDouble.of(Double.parseDouble(item), 0));
+						} catch (NumberFormatException e3) {
+							throw e;
+						}
+					}
+				}
 				break;
-			
+
 			case UNARY_OPERATOR:
 				if (stack.size() < 1)
 					throw new IllegalStateException(String.format(
 							"Attempted to call unary operator %s with only %d arguments.",
 							item, stack.size()));
-				
+
 				// get one argument and operator, then apply!
 				final T o = stack.pop();
 				final UnaryOperator<T> unaryOperator = this.unaryOperators
 						.get(item);
-				
+
 				stack.push(unaryOperator.apply(o));
 				break;
 			default:
 				throw new AssertionError(
 						String.format("Internal error: Invalid token type %s.",
 								this.getTokenType(item)));
-			
+
 			}
 		}
-		
+
 		// return answer, or throw an exception if I can't
 		if (stack.size() > 1)
 			throw new IllegalStateException(
diff --git a/src/main/java/sevenUnits/utils/NameSymbol.java b/src/main/java/sevenUnits/utils/NameSymbol.java
index 9388f63..49c44fa 100644
--- a/src/main/java/sevenUnits/utils/NameSymbol.java
+++ b/src/main/java/sevenUnits/utils/NameSymbol.java
@@ -33,7 +33,7 @@ import java.util.Set;
 public final class NameSymbol {
 	public static final NameSymbol EMPTY = new NameSymbol(Optional.empty(),
 			Optional.empty(), new HashSet<>());
-	
+
 	/**
 	 * Creates a {@code NameSymbol}, ensuring that if primaryName is null and
 	 * otherNames is not empty, one name is moved from otherNames to primaryName
@@ -43,7 +43,7 @@ public final class NameSymbol {
 	private static final NameSymbol create(final String name,
 			final String symbol, final Set<String> otherNames) {
 		final Optional<String> primaryName;
-		
+
 		if (name == null && !otherNames.isEmpty()) {
 			// get primary name and remove it from savedNames
 			final Iterator<String> it = otherNames.iterator();
@@ -53,11 +53,11 @@ public final class NameSymbol {
 		} else {
 			primaryName = Optional.ofNullable(name);
 		}
-		
+
 		return new NameSymbol(primaryName, Optional.ofNullable(symbol),
 				otherNames);
 	}
-	
+
 	/**
 	 * Gets a {@code NameSymbol} with a primary name, a symbol and no other
 	 * names.
@@ -72,7 +72,7 @@ public final class NameSymbol {
 		return new NameSymbol(Optional.of(name), Optional.of(symbol),
 				new HashSet<>());
 	}
-	
+
 	/**
 	 * Gets a {@code NameSymbol} with a primary name, a symbol and additional
 	 * names.
@@ -90,7 +90,7 @@ public final class NameSymbol {
 				new HashSet<>(Objects.requireNonNull(otherNames,
 						"otherNames must not be null.")));
 	}
-	
+
 	/**
 	 * h * Gets a {@code NameSymbol} with a primary name, a symbol and additional
 	 * names.
@@ -108,7 +108,7 @@ public final class NameSymbol {
 				new HashSet<>(Arrays.asList(Objects.requireNonNull(otherNames,
 						"otherNames must not be null."))));
 	}
-	
+
 	/**
 	 * Gets a {@code NameSymbol} with a primary name, no symbol, and no other
 	 * names.
@@ -122,7 +122,7 @@ public final class NameSymbol {
 		return new NameSymbol(Optional.of(name), Optional.empty(),
 				new HashSet<>());
 	}
-	
+
 	/**
 	 * Gets a {@code NameSymbol} with a primary name, a symbol and additional
 	 * names.
@@ -145,7 +145,7 @@ public final class NameSymbol {
 		return NameSymbol.create(name, symbol,
 				otherNames == null ? new HashSet<>() : new HashSet<>(otherNames));
 	}
-	
+
 	/**
 	 * h * Gets a {@code NameSymbol} with a primary name, a symbol and additional
 	 * names.
@@ -168,7 +168,7 @@ public final class NameSymbol {
 		return create(name, symbol, otherNames == null ? new HashSet<>()
 				: new HashSet<>(Arrays.asList(otherNames)));
 	}
-	
+
 	/**
 	 * Gets a {@code NameSymbol} with a symbol and no names.
 	 * 
@@ -181,12 +181,12 @@ public final class NameSymbol {
 		return new NameSymbol(Optional.empty(), Optional.of(symbol),
 				new HashSet<>());
 	}
-	
+
 	private final Optional<String> primaryName;
 	private final Optional<String> symbol;
-	
+
 	private final Set<String> otherNames;
-	
+
 	/**
 	 * Creates the {@code NameSymbol}.
 	 * 
@@ -202,12 +202,12 @@ public final class NameSymbol {
 		this.symbol = symbol;
 		otherNames.remove(null);
 		this.otherNames = Collections.unmodifiableSet(otherNames);
-		
+
 		if (this.primaryName.isEmpty()) {
 			assert this.otherNames.isEmpty();
 		}
 	}
-	
+
 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj)
@@ -232,7 +232,7 @@ public final class NameSymbol {
 			return false;
 		return true;
 	}
-	
+
 	/**
 	 * @return otherNames
 	 * @since 2019-10-21
@@ -240,7 +240,7 @@ public final class NameSymbol {
 	public final Set<String> getOtherNames() {
 		return this.otherNames;
 	}
-	
+
 	/**
 	 * @return primaryName
 	 * @since 2019-10-21
@@ -248,7 +248,7 @@ public final class NameSymbol {
 	public final Optional<String> getPrimaryName() {
 		return this.primaryName;
 	}
-	
+
 	/**
 	 * @return symbol
 	 * @since 2019-10-21
@@ -256,7 +256,7 @@ public final class NameSymbol {
 	public final Optional<String> getSymbol() {
 		return this.symbol;
 	}
-	
+
 	@Override
 	public int hashCode() {
 		final int prime = 31;
@@ -269,7 +269,7 @@ public final class NameSymbol {
 				+ (this.symbol == null ? 0 : this.symbol.hashCode());
 		return result;
 	}
-	
+
 	/**
 	 * @return true iff this {@code NameSymbol} contains no names or symbols.
 	 */
@@ -277,7 +277,7 @@ public final class NameSymbol {
 		// if primaryName is empty, otherNames must also be empty
 		return this.primaryName.isEmpty() && this.symbol.isEmpty();
 	}
-	
+
 	@Override
 	public String toString() {
 		if (this.isEmpty())
@@ -288,7 +288,7 @@ public final class NameSymbol {
 		else
 			return this.primaryName.orElseGet(this.symbol::orElseThrow);
 	}
-	
+
 	/**
 	 * Creates and returns a copy of this {@code NameSymbol} with the provided
 	 * extra name. If this {@code NameSymbol} has a primary name, the provided
diff --git a/src/main/java/sevenUnits/utils/Nameable.java b/src/main/java/sevenUnits/utils/Nameable.java
index e469d04..3959a64 100644
--- a/src/main/java/sevenUnits/utils/Nameable.java
+++ b/src/main/java/sevenUnits/utils/Nameable.java
@@ -35,14 +35,14 @@ public interface Nameable {
 		final NameSymbol ns = this.getNameSymbol();
 		return ns.getPrimaryName().or(ns::getSymbol).orElse("Unnamed");
 	}
-	
+
 	/**
 	 * @return a {@code NameSymbol} that contains this object's primary name,
 	 *         symbol and other names
 	 * @since 2020-09-07
 	 */
 	NameSymbol getNameSymbol();
-	
+
 	/**
 	 * @return set of alternate names
 	 * @since 2020-09-07
@@ -50,7 +50,7 @@ public interface Nameable {
 	default Set<String> getOtherNames() {
 		return this.getNameSymbol().getOtherNames();
 	}
-	
+
 	/**
 	 * @return preferred name of object
 	 * @since 2020-09-07
@@ -58,7 +58,7 @@ public interface Nameable {
 	default Optional<String> getPrimaryName() {
 		return this.getNameSymbol().getPrimaryName();
 	}
-	
+
 	/**
 	 * @return a short name for the object - if there's a symbol, it's that,
 	 *         otherwise the symbol, otherwise "Unnamed"
@@ -68,7 +68,7 @@ public interface Nameable {
 		final NameSymbol ns = this.getNameSymbol();
 		return ns.getSymbol().or(ns::getPrimaryName).orElse("Unnamed");
 	}
-	
+
 	/**
 	 * @return short symbol representing object
 	 * @since 2020-09-07
diff --git a/src/main/java/sevenUnits/utils/ObjectProduct.java b/src/main/java/sevenUnits/utils/ObjectProduct.java
index 66bb773..5a29d79 100644
--- a/src/main/java/sevenUnits/utils/ObjectProduct.java
+++ b/src/main/java/sevenUnits/utils/ObjectProduct.java
@@ -44,7 +44,7 @@ public class ObjectProduct<T> implements Nameable {
 	public static final <T> ObjectProduct<T> empty() {
 		return new ObjectProduct<>(new HashMap<>());
 	}
-	
+
 	/**
 	 * Gets an {@code ObjectProduct} from an object-to-integer mapping
 	 * 
@@ -57,7 +57,7 @@ public class ObjectProduct<T> implements Nameable {
 			final Map<T, Integer> map) {
 		return new ObjectProduct<>(new HashMap<>(map));
 	}
-	
+
 	/**
 	 * Gets an ObjectProduct that has one of the inputted argument, and nothing
 	 * else.
@@ -73,7 +73,7 @@ public class ObjectProduct<T> implements Nameable {
 		map.put(object, 1);
 		return new ObjectProduct<>(map);
 	}
-	
+
 	/**
 	 * The objects that make up the product, mapped to their exponents. This map
 	 * treats zero as null, and is immutable.
@@ -81,12 +81,12 @@ public class ObjectProduct<T> implements Nameable {
 	 * @since 2019-10-16
 	 */
 	final Map<T, Integer> exponents;
-	
+
 	/**
 	 * The object's name and symbol
 	 */
 	private final NameSymbol nameSymbol;
-	
+
 	/**
 	 * Creates a {@code ObjectProduct} without a name/symbol.
 	 * 
@@ -96,7 +96,7 @@ public class ObjectProduct<T> implements Nameable {
 	ObjectProduct(final Map<T, Integer> exponents) {
 		this(exponents, NameSymbol.EMPTY);
 	}
-	
+
 	/**
 	 * Creates the {@code ObjectProduct}.
 	 * 
@@ -110,7 +110,7 @@ public class ObjectProduct<T> implements Nameable {
 						e -> !Integer.valueOf(0).equals(e.getValue())));
 		this.nameSymbol = nameSymbol;
 	}
-	
+
 	/**
 	 * Calculates the quotient of two products
 	 *
@@ -125,17 +125,17 @@ public class ObjectProduct<T> implements Nameable {
 		final Set<T> objects = new HashSet<>();
 		objects.addAll(this.getBaseSet());
 		objects.addAll(other.getBaseSet());
-		
+
 		// get a list of all exponents
 		final Map<T, Integer> map = new HashMap<>(objects.size());
 		for (final T key : objects) {
 			map.put(key, this.getExponent(key) - other.getExponent(key));
 		}
-		
+
 		// create the product
 		return new ObjectProduct<>(map);
 	}
-	
+
 	// this method relies on the use of ZeroIsNullMap
 	@Override
 	public boolean equals(final Object obj) {
@@ -146,7 +146,7 @@ public class ObjectProduct<T> implements Nameable {
 		final ObjectProduct<?> other = (ObjectProduct<?>) obj;
 		return Objects.equals(this.exponents, other.exponents);
 	}
-	
+
 	/**
 	 * @return immutable map mapping objects to exponents
 	 * @since 2019-10-16
@@ -154,7 +154,7 @@ public class ObjectProduct<T> implements Nameable {
 	public Map<T, Integer> exponentMap() {
 		return this.exponents;
 	}
-	
+
 	/**
 	 * @return a set of all of the base objects with non-zero exponents that make
 	 *         up this dimension.
@@ -163,7 +163,7 @@ public class ObjectProduct<T> implements Nameable {
 	 */
 	public final Set<T> getBaseSet() {
 		final Set<T> dimensions = new HashSet<>();
-		
+
 		// add all dimensions with a nonzero exponent - zero exponents shouldn't
 		// be there in the first place
 		for (final T dimension : this.exponents.keySet()) {
@@ -171,10 +171,10 @@ public class ObjectProduct<T> implements Nameable {
 				dimensions.add(dimension);
 			}
 		}
-		
+
 		return dimensions;
 	}
-	
+
 	/**
 	 * Gets the exponent for a specific dimension.
 	 * 
@@ -186,17 +186,17 @@ public class ObjectProduct<T> implements Nameable {
 	public int getExponent(final T dimension) {
 		return this.exponents.getOrDefault(dimension, 0);
 	}
-	
+
 	@Override
 	public NameSymbol getNameSymbol() {
 		return this.nameSymbol;
 	}
-	
+
 	@Override
 	public int hashCode() {
 		return Objects.hash(this.exponents);
 	}
-	
+
 	/**
 	 * @return true if this product is a single object, i.e. it has one exponent
 	 *         of one and no other nonzero exponents
@@ -214,7 +214,7 @@ public class ObjectProduct<T> implements Nameable {
 		}
 		return oneCount == 1 && !twoOrMore;
 	}
-	
+
 	/**
 	 * Multiplies this product by another
 	 *
@@ -229,17 +229,17 @@ public class ObjectProduct<T> implements Nameable {
 		final Set<T> objects = new HashSet<>();
 		objects.addAll(this.getBaseSet());
 		objects.addAll(other.getBaseSet());
-		
+
 		// get a list of all exponents
 		final Map<T, Integer> map = new HashMap<>(objects.size());
 		for (final T key : objects) {
 			map.put(key, this.getExponent(key) + other.getExponent(key));
 		}
-		
+
 		// create the product
 		return new ObjectProduct<>(map);
 	}
-	
+
 	/**
 	 * Returns this product, but to an exponent
 	 * 
@@ -254,7 +254,7 @@ public class ObjectProduct<T> implements Nameable {
 		}
 		return new ObjectProduct<>(map);
 	}
-	
+
 	/**
 	 * Converts this product to a string using the objects'
 	 * {@link Object#toString()} method (or {@link Nameable#getShortName} if
@@ -271,7 +271,7 @@ public class ObjectProduct<T> implements Nameable {
 				.toString(o -> o instanceof Nameable ? ((Nameable) o).getShortName()
 						: o.toString());
 	}
-	
+
 	/**
 	 * Converts this product to a string. The objects that make up this product
 	 * are represented by {@code objectToString}
@@ -283,7 +283,7 @@ public class ObjectProduct<T> implements Nameable {
 	public String toString(final Function<T, String> objectToString) {
 		final List<String> positiveStringComponents = new ArrayList<>();
 		final List<String> negativeStringComponents = new ArrayList<>();
-		
+
 		// for each base object that makes up this object, add it and its exponent
 		for (final T object : this.getBaseSet()) {
 			final int exponent = this.exponents.get(object);
@@ -297,15 +297,15 @@ public class ObjectProduct<T> implements Nameable {
 						objectToString.apply(object), -exponent));
 			}
 		}
-		
+
 		final String positiveString = positiveStringComponents.isEmpty() ? "1"
 				: String.join(" * ", positiveStringComponents);
 		final String negativeString = negativeStringComponents.isEmpty() ? ""
 				: " / " + String.join(" * ", negativeStringComponents);
-		
+
 		return positiveString + negativeString;
 	}
-	
+
 	/**
 	 * @return named version of this {@code ObjectProduct}, using data from
 	 *         {@code nameSymbol}
diff --git a/src/main/java/sevenUnits/utils/SemanticVersionNumber.java b/src/main/java/sevenUnits/utils/SemanticVersionNumber.java
index e80e16e..fc47baa 100644
--- a/src/main/java/sevenUnits/utils/SemanticVersionNumber.java
+++ b/src/main/java/sevenUnits/utils/SemanticVersionNumber.java
@@ -61,7 +61,7 @@ public final class SemanticVersionNumber
 		private final int patch;
 		private final List<String> preReleaseIdentifiers;
 		private final List<String> buildMetadata;
-		
+
 		/**
 		 * Creates a builder which can be used to create a
 		 * {@code SemanticVersionNumber}
@@ -79,7 +79,7 @@ public final class SemanticVersionNumber
 			this.preReleaseIdentifiers = new ArrayList<>();
 			this.buildMetadata = new ArrayList<>();
 		}
-		
+
 		/**
 		 * @return version number created by this builder
 		 * @since v0.4.0
@@ -89,7 +89,7 @@ public final class SemanticVersionNumber
 			return new SemanticVersionNumber(this.major, this.minor, this.patch,
 					this.preReleaseIdentifiers, this.buildMetadata);
 		}
-		
+
 		/**
 		 * Adds one or more build metadata identifiers
 		 *
@@ -109,7 +109,7 @@ public final class SemanticVersionNumber
 			}
 			return this;
 		}
-		
+
 		/**
 		 * Adds one or more build metadata identifiers
 		 *
@@ -129,7 +129,7 @@ public final class SemanticVersionNumber
 			}
 			return this;
 		}
-		
+
 		@Override
 		public boolean equals(Object obj) {
 			if (this == obj)
@@ -142,13 +142,13 @@ public final class SemanticVersionNumber
 					&& this.patch == other.patch && Objects.equals(
 							this.preReleaseIdentifiers, other.preReleaseIdentifiers);
 		}
-		
+
 		@Override
 		public int hashCode() {
 			return Objects.hash(this.buildMetadata, this.major, this.minor,
 					this.patch, this.preReleaseIdentifiers);
 		}
-		
+
 		/**
 		 * Adds one or more numeric identifiers to the version number
 		 *
@@ -167,7 +167,7 @@ public final class SemanticVersionNumber
 			}
 			return this;
 		}
-		
+
 		/**
 		 * Adds one or more pre-release identifier(s) to the version number
 		 *
@@ -187,7 +187,7 @@ public final class SemanticVersionNumber
 			}
 			return this;
 		}
-		
+
 		/**
 		 * Adds one or more pre-release identifier(s) to the version number
 		 *
@@ -207,7 +207,7 @@ public final class SemanticVersionNumber
 			}
 			return this;
 		}
-		
+
 		/**
 		 * Adds a string identifier and an integer identifer to pre-release data
 		 *
@@ -229,13 +229,13 @@ public final class SemanticVersionNumber
 			this.preReleaseIdentifiers.add(Integer.toString(identifier2));
 			return this;
 		}
-		
+
 		@Override
 		public String toString() {
 			return "Semantic Version Builder: " + this.build().toString();
 		}
 	}
-	
+
 	/**
 	 * An alternative comparison method for version numbers. This uses the
 	 * version's natural order, but the build metadata will be compared (using
@@ -257,21 +257,21 @@ public final class SemanticVersionNumber
 				return naturalComparison;
 		};
 	};
-	
+
 	/** The alphanumeric pattern all identifiers must follow */
 	private static final Pattern VALID_IDENTIFIER = Pattern
 			.compile("[0-9A-Za-z-]+");
-	
+
 	/** The numeric pattern which causes special behaviour */
 	private static final Pattern NUMERIC_IDENTIFER = Pattern.compile("[0-9]+");
-	
+
 	/** The pattern for a version number */
 	private static final Pattern VERSION_NUMBER = Pattern
 			.compile("(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)\\.(0|[1-9][0-9]*)" // main
 					// version
 					+ "(?:-([0-9a-zA-Z-]+(?:\\.[0-9a-zA-Z-]+)*))?" // pre-release
 					+ "(?:\\+([0-9a-zA-Z-]+(?:\\.[0-9a-zA-Z-]+)*))?"); // build data
-	
+
 	/**
 	 * Creates a builder that can be used to create a version number
 	 *
@@ -296,7 +296,7 @@ public final class SemanticVersionNumber
 					"Patch version must be non-negative.");
 		return new SemanticVersionNumber.Builder(major, minor, patch);
 	}
-	
+
 	/**
 	 * Compares two lists of strings based on SemVer's precedence rules
 	 *
@@ -311,24 +311,24 @@ public final class SemanticVersionNumber
 		// test pre-release size
 		final int aSize = a.size();
 		final int bSize = b.size();
-		
+
 		// no identifiers is greater than any identifiers
 		if (aSize != 0 && bSize == 0)
 			return -1;
 		else if (aSize == 0 && bSize != 0)
 			return 1;
-		
+
 		// test identifiers one by one
 		for (int i = 0; i < Math.min(aSize, bSize); i++) {
 			final String aElement = a.get(i);
 			final String bElement = b.get(i);
-			
+
 			if (NUMERIC_IDENTIFER.matcher(aElement).matches()) {
 				if (NUMERIC_IDENTIFER.matcher(bElement).matches()) {
 					// both are numbers, compare them
 					final int aNumber = Integer.parseInt(aElement);
 					final int bNumber = Integer.parseInt(bElement);
-					
+
 					if (aNumber < bNumber)
 						return -1;
 					else if (aNumber > bNumber)
@@ -350,7 +350,7 @@ public final class SemanticVersionNumber
 				}
 			}
 		}
-		
+
 		// we just tested the stuff that's in common, maybe someone has more
 		if (aSize < bSize)
 			return -1;
@@ -359,7 +359,7 @@ public final class SemanticVersionNumber
 		else
 			return 0;
 	}
-	
+
 	/**
 	 * Gets a version number from a string in the official format
 	 *
@@ -377,12 +377,12 @@ public final class SemanticVersionNumber
 			throw new IllegalArgumentException(
 					String.format("Provided string \"%s\" is not a version number",
 							versionString));
-		
+
 		// main parts
 		final int major = Integer.parseInt(m.group(1));
 		final int minor = Integer.parseInt(m.group(2));
 		final int patch = Integer.parseInt(m.group(3));
-		
+
 		// pre release
 		final List<String> preRelease;
 		if (m.group(4) == null) {
@@ -390,7 +390,7 @@ public final class SemanticVersionNumber
 		} else {
 			preRelease = Arrays.asList(m.group(4).split("\\."));
 		}
-		
+
 		// build metadata
 		final List<String> buildMetadata;
 		if (m.group(5) == null) {
@@ -398,12 +398,12 @@ public final class SemanticVersionNumber
 		} else {
 			buildMetadata = Arrays.asList(m.group(5).split("\\."));
 		}
-		
+
 		// return number
 		return new SemanticVersionNumber(major, minor, patch, preRelease,
 				buildMetadata);
 	}
-	
+
 	/**
 	 * Tests whether a string is a valid Semantic Version string
 	 * 
@@ -415,7 +415,7 @@ public final class SemanticVersionNumber
 	public static final boolean isValidVersionString(String versionString) {
 		return VERSION_NUMBER.matcher(versionString).matches();
 	}
-	
+
 	/**
 	 * Creates a simple pre-release version number of the form
 	 * MAJOR.MINOR.PATH-TYPE.NUMBER (e.g. 1.2.3-alpha.4).
@@ -454,7 +454,7 @@ public final class SemanticVersionNumber
 				List.of(preReleaseType, Integer.toString(preReleaseNumber)),
 				List.of());
 	}
-	
+
 	/**
 	 * Creates a {@code SemanticVersionNumber} instance without pre-release
 	 * identifiers or build metadata.
@@ -484,14 +484,14 @@ public final class SemanticVersionNumber
 		return new SemanticVersionNumber(major, minor, patch, List.of(),
 				List.of());
 	}
-	
+
 	// parts of the version number
 	private final int major;
 	private final int minor;
 	private final int patch;
 	private final List<String> preReleaseIdentifiers;
 	private final List<String> buildMetadata;
-	
+
 	/**
 	 * Creates a version number
 	 *
@@ -511,7 +511,7 @@ public final class SemanticVersionNumber
 		this.preReleaseIdentifiers = preReleaseIdentifiers;
 		this.buildMetadata = buildMetadata;
 	}
-	
+
 	/**
 	 * @return build metadata (empty if there is none)
 	 * @since v0.4.0
@@ -520,7 +520,7 @@ public final class SemanticVersionNumber
 	public List<String> buildMetadata() {
 		return Collections.unmodifiableList(this.buildMetadata);
 	}
-	
+
 	/**
 	 * Compares two version numbers according to the official Semantic Versioning
 	 * order.
@@ -538,23 +538,23 @@ public final class SemanticVersionNumber
 			return -1;
 		else if (this.major > o.major)
 			return 1;
-		
+
 		if (this.minor < o.minor)
 			return -1;
 		else if (this.minor > o.minor)
 			return 1;
-		
+
 		if (this.patch < o.patch)
 			return -1;
 		else if (this.patch > o.patch)
 			return 1;
-			
+
 		// now we just compare pre-release identifiers
 		// (remember: build metadata is ignored)
 		return SemanticVersionNumber.compareIdentifiers(
 				this.preReleaseIdentifiers, o.preReleaseIdentifiers);
 	}
-	
+
 	/**
 	 * Determines the compatibility of code written for this version to
 	 * {@code other}. More specifically:
@@ -590,11 +590,11 @@ public final class SemanticVersionNumber
 	 */
 	public boolean compatibleWith(SemanticVersionNumber other) {
 		Objects.requireNonNull(other, "other may not be null");
-		
+
 		return this.compareTo(other) == 0 || this.major != 0
 				&& this.major == other.major && this.compareTo(other) < 0;
 	}
-	
+
 	@Override
 	public boolean equals(Object obj) {
 		if (this == obj)
@@ -621,7 +621,7 @@ public final class SemanticVersionNumber
 			return false;
 		return true;
 	}
-	
+
 	@Override
 	public int hashCode() {
 		final int prime = 31;
@@ -635,7 +635,7 @@ public final class SemanticVersionNumber
 				: this.preReleaseIdentifiers.hashCode());
 		return result;
 	}
-	
+
 	/**
 	 * @return true iff this version is stable (major version > 0 and not a
 	 *         pre-release)
@@ -645,7 +645,7 @@ public final class SemanticVersionNumber
 	public boolean isStable() {
 		return this.major > 0 && this.preReleaseIdentifiers.isEmpty();
 	}
-	
+
 	/**
 	 * @return the MAJOR version number, incremented when you make backwards
 	 *         incompatible API changes
@@ -655,7 +655,7 @@ public final class SemanticVersionNumber
 	public int majorVersion() {
 		return this.major;
 	}
-	
+
 	/**
 	 * @return the MINOR version number, incremented when you add backwards
 	 *         compatible functionality
@@ -665,7 +665,7 @@ public final class SemanticVersionNumber
 	public int minorVersion() {
 		return this.minor;
 	}
-	
+
 	/**
 	 * @return the PATCH version number, incremented when you make backwards
 	 *         compatible bug fixes
@@ -675,7 +675,7 @@ public final class SemanticVersionNumber
 	public int patchVersion() {
 		return this.patch;
 	}
-	
+
 	/**
 	 * @return identifiers describing this pre-release (empty if not a
 	 *         pre-release)
@@ -685,7 +685,7 @@ public final class SemanticVersionNumber
 	public List<String> preReleaseIdentifiers() {
 		return Collections.unmodifiableList(this.preReleaseIdentifiers);
 	}
-	
+
 	/**
 	 * Converts a version number to a string using the official SemVer format.
 	 * The core of a version is MAJOR.MINOR.PATCH, without zero-padding. If
diff --git a/src/main/java/sevenUnits/utils/UncertainDouble.java b/src/main/java/sevenUnits/utils/UncertainDouble.java
index ac523b3..66d8103 100644
--- a/src/main/java/sevenUnits/utils/UncertainDouble.java
+++ b/src/main/java/sevenUnits/utils/UncertainDouble.java
@@ -23,7 +23,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 /**
- * A double with an associated uncertainty value. For example, 3.2 ± 0.2.
+ * A double with an associated uncertainty value. For example, 3.2 � 0.2.
  * <p>
  * All methods in this class throw a NullPointerException if any of their
  * arguments is null.
@@ -35,20 +35,20 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	 * The exact value 0
 	 */
 	public static final UncertainDouble ZERO = UncertainDouble.of(0, 0);
-	
+
 	static final String NUMBER_REGEX = "(\\d+(?:[\\.,]\\d+))";
-	
+
 	/**
 	 * A regular expression that can recognize toString forms
 	 */
 	static final Pattern TO_STRING = Pattern.compile(NUMBER_REGEX
-			// optional "± [number]"
-			+ "(?:\\s*(?:±|\\+-)\\s*" + NUMBER_REGEX + ")?");
-	
+			// optional "� [number]"
+			+ "(?:\\s*(?:�|\\+-)\\s*" + NUMBER_REGEX + ")?");
+
 	/**
 	 * Gets an UncertainDouble from a double string. The uncertainty of the
 	 * double will be one of the lowest decimal place of the number. For example,
-	 * "12345.678" will become 12345.678 ± 0.001.
+	 * "12345.678" will become 12345.678 � 0.001.
 	 * 
 	 * @throws NumberFormatException if the argument is not a number
 	 *
@@ -59,13 +59,13 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		final double uncertainty = Math.pow(10, -value.scale());
 		return UncertainDouble.of(value.doubleValue(), uncertainty);
 	}
-	
+
 	/**
 	 * Parses a string in the form of {@link UncertainDouble#toString(boolean)}
 	 * and returns the corresponding {@code UncertainDouble} instance.
 	 * <p>
 	 * This method allows some alternative forms of the string representation,
-	 * such as using "+-" instead of "±".
+	 * such as using "+-" instead of "�".
 	 * 
 	 * @param s string to parse
 	 * @return {@code UncertainDouble} instance
@@ -75,11 +75,11 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public static final UncertainDouble fromString(String s) {
 		Objects.requireNonNull(s, "s may not be null");
 		final Matcher matcher = TO_STRING.matcher(s);
-		
+
 		if (!matcher.matches())
 			throw new IllegalArgumentException(
 					"Could not parse stirng \"" + s + "\".");
-		
+
 		double value, uncertainty;
 		try {
 			value = Double.parseDouble(matcher.group(1));
@@ -87,7 +87,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 			throw new IllegalArgumentException(
 					"String " + s + " not in correct format.");
 		}
-		
+
 		final String uncertaintyString = matcher.group(2);
 		if (uncertaintyString == null) {
 			uncertainty = 0;
@@ -99,10 +99,10 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 						"String " + s + " not in correct format.");
 			}
 		}
-		
+
 		return UncertainDouble.of(value, uncertainty);
 	}
-	
+
 	/**
 	 * Gets an {@code UncertainDouble} from its value and <b>absolute</b>
 	 * uncertainty.
@@ -112,7 +112,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public static final UncertainDouble of(double value, double uncertainty) {
 		return new UncertainDouble(value, uncertainty);
 	}
-	
+
 	/**
 	 * Gets an {@code UncertainDouble} from its value and <b>relative</b>
 	 * uncertainty.
@@ -123,11 +123,11 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 			double relativeUncertainty) {
 		return new UncertainDouble(value, value * relativeUncertainty);
 	}
-	
+
 	private final double value;
-	
+
 	private final double uncertainty;
-	
+
 	/**
 	 * @param value
 	 * @param uncertainty
@@ -138,13 +138,13 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		// uncertainty should only ever be positive
 		this.uncertainty = Math.abs(uncertainty);
 	}
-	
+
 	/**
 	 * Compares this {@code UncertainDouble} with another
 	 * {@code UncertainDouble}.
 	 * <p>
-	 * This method only compares the values, not the uncertainties. So 3.1 ± 0.5
-	 * is considered less than 3.2 ± 0.5, even though they are equivalent.
+	 * This method only compares the values, not the uncertainties. So 3.1 � 0.5
+	 * is considered less than 3.2 � 0.5, even though they are equivalent.
 	 * <p>
 	 * <b>Note:</b> The natural ordering of this class is inconsistent with
 	 * equals. Specifically, if two {@code UncertainDouble} instances {@code a}
@@ -156,7 +156,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final int compareTo(UncertainDouble o) {
 		return Double.compare(this.value, o.value);
 	}
-	
+
 	/**
 	 * Returns the quotient of {@code this} and {@code other}.
 	 * 
@@ -167,7 +167,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return UncertainDouble.ofRelative(this.value / other.value, Math
 				.hypot(this.relativeUncertainty(), other.relativeUncertainty()));
 	}
-	
+
 	/**
 	 * Returns the quotient of {@code this} and the exact value {@code other}.
 	 * 
@@ -176,7 +176,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final UncertainDouble dividedByExact(double other) {
 		return UncertainDouble.of(this.value / other, this.uncertainty / other);
 	}
-	
+
 	@Override
 	public final boolean equals(Object obj) {
 		if (this == obj)
@@ -190,7 +190,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 			return false;
 		return true;
 	}
-	
+
 	/**
 	 * @param other another {@code UncertainDouble}
 	 * @return true iff this and {@code other} are within each other's
@@ -202,7 +202,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return Math.abs(this.value - other.value) <= Math.min(this.uncertainty,
 				other.uncertainty);
 	}
-	
+
 	/**
 	 * Gets the preferred scale for rounding a value for toString.
 	 * 
@@ -217,19 +217,19 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		// the value is rounded to the same number of decimal places as the
 		// uncertainty.
 		final BigDecimal bigUncertainty = BigDecimal.valueOf(this.uncertainty);
-		
+
 		// the scale that will give the uncertainty two decimal places
 		final int twoDecimalPlacesScale = bigUncertainty.scale()
 				- bigUncertainty.precision() + 2;
 		final BigDecimal roundedUncertainty = bigUncertainty
 				.setScale(twoDecimalPlacesScale, RoundingMode.HALF_EVEN);
-		
+
 		if (roundedUncertainty.unscaledValue().intValue() >= 20)
 			return twoDecimalPlacesScale - 1; // one decimal place
 		else
 			return twoDecimalPlacesScale;
 	}
-	
+
 	@Override
 	public final int hashCode() {
 		final int prime = 31;
@@ -238,7 +238,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		result = prime * result + Double.hashCode(this.uncertainty);
 		return result;
 	}
-	
+
 	/**
 	 * @return true iff the value has no uncertainty
 	 * 
@@ -247,7 +247,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final boolean isExact() {
 		return this.uncertainty == 0;
 	}
-	
+
 	/**
 	 * Returns the difference of {@code this} and {@code other}.
 	 * 
@@ -258,7 +258,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return UncertainDouble.of(this.value - other.value,
 				Math.hypot(this.uncertainty, other.uncertainty));
 	}
-	
+
 	/**
 	 * Returns the difference of {@code this} and the exact value {@code other}.
 	 * 
@@ -267,7 +267,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final UncertainDouble minusExact(double other) {
 		return UncertainDouble.of(this.value - other, this.uncertainty);
 	}
-	
+
 	/**
 	 * Returns the sum of {@code this} and {@code other}.
 	 * 
@@ -278,7 +278,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return UncertainDouble.of(this.value + other.value,
 				Math.hypot(this.uncertainty, other.uncertainty));
 	}
-	
+
 	/**
 	 * Returns the sum of {@code this} and the exact value {@code other}.
 	 * 
@@ -287,7 +287,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final UncertainDouble plusExact(double other) {
 		return UncertainDouble.of(this.value + other, this.uncertainty);
 	}
-	
+
 	/**
 	 * @return relative uncertainty
 	 * @since 2020-09-07
@@ -295,7 +295,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final double relativeUncertainty() {
 		return this.uncertainty / this.value;
 	}
-	
+
 	/**
 	 * Returns the product of {@code this} and {@code other}.
 	 * 
@@ -306,7 +306,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return UncertainDouble.ofRelative(this.value * other.value, Math
 				.hypot(this.relativeUncertainty(), other.relativeUncertainty()));
 	}
-	
+
 	/**
 	 * Returns the product of {@code this} and the exact value {@code other}.
 	 * 
@@ -315,7 +315,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final UncertainDouble timesExact(double other) {
 		return UncertainDouble.of(this.value * other, this.uncertainty * other);
 	}
-	
+
 	/**
 	 * Returns the result of {@code this} raised to the exponent {@code other}.
 	 * 
@@ -323,15 +323,15 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	 */
 	public final UncertainDouble toExponent(UncertainDouble other) {
 		Objects.requireNonNull(other, "other may not be null");
-		
+
 		final double result = Math.pow(this.value, other.value);
 		final double relativeUncertainty = Math.hypot(
 				other.value * this.relativeUncertainty(),
 				Math.log(this.value) * other.uncertainty);
-		
+
 		return UncertainDouble.ofRelative(result, relativeUncertainty);
 	}
-	
+
 	/**
 	 * Returns the result of {@code this} raised the exact exponent
 	 * {@code other}.
@@ -342,7 +342,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 		return UncertainDouble.ofRelative(Math.pow(this.value, other),
 				this.relativeUncertainty() * other);
 	}
-	
+
 	/**
 	 * Returns a string representation of this {@code UncertainDouble}.
 	 * <p>
@@ -354,8 +354,8 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	 * Examples:
 	 * 
 	 * <pre>
-	 * UncertainDouble.of(3.27, 0.22).toString() = "3.3 ± 0.2"
-	 * UncertainDouble.of(3.27, 0.13).toString() = "3.27 ± 0.13"
+	 * UncertainDouble.of(3.27, 0.22).toString() = "3.3 � 0.2"
+	 * UncertainDouble.of(3.27, 0.13).toString() = "3.27 � 0.13"
 	 * UncertainDouble.of(-5.01, 0).toString() = "-5.01"
 	 * </pre>
 	 * 
@@ -365,12 +365,12 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final String toString() {
 		return this.toString(!this.isExact(), RoundingMode.HALF_EVEN);
 	}
-	
+
 	/**
 	 * Returns a string representation of this {@code UncertainDouble}.
 	 * <p>
 	 * If {@code showUncertainty} is true, the string will be of the form "VALUE
-	 * ± UNCERTAINTY", and if it is false the string will be of the form "VALUE"
+	 * � UNCERTAINTY", and if it is false the string will be of the form "VALUE"
 	 * <p>
 	 * VALUE represents a string representation of this {@code UncertainDouble}'s
 	 * value. If the uncertainty is non-zero, the string will be rounded to the
@@ -385,11 +385,11 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	 * 
 	 * <pre>
 	 * UncertainDouble.of(3.27, 0.22).toString(false) = "3.3"
-	 * UncertainDouble.of(3.27, 0.22).toString(true) = "3.3 ± 0.2"
+	 * UncertainDouble.of(3.27, 0.22).toString(true) = "3.3 � 0.2"
 	 * UncertainDouble.of(3.27, 0.13).toString(false) = "3.27"
-	 * UncertainDouble.of(3.27, 0.13).toString(true) = "3.27 ± 0.13"
+	 * UncertainDouble.of(3.27, 0.13).toString(true) = "3.27 � 0.13"
 	 * UncertainDouble.of(-5.01, 0).toString(false) = "-5.01"
-	 * UncertainDouble.of(-5.01, 0).toString(true) = "-5.01 ± 0.0"
+	 * UncertainDouble.of(-5.01, 0).toString(true) = "-5.01 � 0.0"
 	 * </pre>
 	 * 
 	 * @since 2020-09-07
@@ -397,31 +397,31 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final String toString(boolean showUncertainty,
 			RoundingMode roundingMode) {
 		String valueString, uncertaintyString;
-		
+
 		// generate the string representation of value and uncertainty
 		if (this.isExact()) {
 			uncertaintyString = "0.0";
 			valueString = Double.toString(this.value);
-			
+
 		} else {
 			// round the value and uncertainty according to getDisplayScale()
 			final BigDecimal bigValue = BigDecimal.valueOf(this.value);
 			final BigDecimal bigUncertainty = BigDecimal.valueOf(this.uncertainty);
-			
+
 			final int displayScale = this.getDisplayScale();
 			final BigDecimal roundedUncertainty = bigUncertainty
 					.setScale(displayScale, roundingMode);
 			final BigDecimal roundedValue = bigValue.setScale(displayScale,
 					roundingMode);
-			
+
 			valueString = roundedValue.toString();
 			uncertaintyString = roundedUncertainty.toString();
 		}
-		
-		// return "value" or "value ± uncertainty" depending on showUncertainty
-		return valueString + (showUncertainty ? " ± " + uncertaintyString : "");
+
+		// return "value" or "value � uncertainty" depending on showUncertainty
+		return valueString + (showUncertainty ? " � " + uncertaintyString : "");
 	}
-	
+
 	/**
 	 * @return absolute uncertainty
 	 * @since 2020-09-07
@@ -429,7 +429,7 @@ public final class UncertainDouble implements Comparable<UncertainDouble> {
 	public final double uncertainty() {
 		return this.uncertainty;
 	}
-	
+
 	/**
 	 * @return value without uncertainty
 	 * @since 2020-09-07