Revert expressionToRPN to package-private

This resolves the last remaining TODO/FIXME comment

1 files changed, 93 insertions, 95 deletions

diff --git a/src/main/java/sevenUnits/utils/ExpressionParser.java b/src/main/java/sevenUnits/utils/ExpressionParser.java
index 051082d..783a135 100644
--- a/src/main/java/sevenUnits/utils/ExpressionParser.java
+++ b/src/main/java/sevenUnits/utils/ExpressionParser.java
@@ -56,7 +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)
 		 * 
@@ -64,7 +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.
@@ -73,7 +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.
@@ -82,7 +82,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-
+		
 		/**
 		 * A map mapping operator strings to numeric functions.
 		 * 
@@ -90,7 +90,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.5.0
 		 */
 		private final Map<String, PriorityBiFunction<T, UncertainDouble, T>> numericOperators;
-
+		
 		/**
 		 * Creates the {@code Builder}.
 		 * 
@@ -107,7 +107,7 @@ public final class ExpressionParser<T> {
 			this.binaryOperators = new HashMap<>();
 			this.numericOperators = new HashMap<>();
 		}
-
+		
 		/**
 		 * Adds a binary operator to the builder.
 		 * 
@@ -125,7 +125,7 @@ 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<>(
@@ -134,12 +134,12 @@ 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.
@@ -155,7 +155,7 @@ public final class ExpressionParser<T> {
 				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<>(
@@ -164,12 +164,12 @@ public final class ExpressionParser<T> {
 				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.
@@ -181,15 +181,15 @@ 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.
 		 * 
@@ -207,7 +207,7 @@ 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<>(
@@ -220,7 +220,7 @@ 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
@@ -232,7 +232,7 @@ public final class ExpressionParser<T> {
 					this.binaryOperators, this.numericOperators, this.spaceFunction);
 		}
 	}
-
+	
 	/**
 	 * A binary operator with a priority field that determines which operators
 	 * apply first.
@@ -242,8 +242,8 @@ public final class ExpressionParser<T> {
 	 * @since 2019-03-17
 	 * @since v0.2.0
 	 */
-	private static abstract class PriorityBinaryOperator<T>
-			implements BinaryOperator<T>, Comparable<PriorityBinaryOperator<T>> {
+	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
@@ -252,7 +252,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final int priority;
-
+		
 		/**
 		 * Creates the {@code PriorityBinaryOperator}.
 		 * 
@@ -260,10 +260,10 @@ public final class ExpressionParser<T> {
 		 * @since 2019-03-17
 		 * @since v0.2.0
 		 */
-		public PriorityBinaryOperator(final int priority) {
+		public PriorityBiFunction(final int priority) {
 			this.priority = priority;
 		}
-
+		
 		/**
 		 * Compares this object to another by priority.
 		 * 
@@ -275,7 +275,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		@Override
-		public int compareTo(final PriorityBinaryOperator<T> o) {
+		public int compareTo(final PriorityBiFunction<T, U, R> o) {
 			if (this.priority < o.priority)
 				return -1;
 			else if (this.priority > o.priority)
@@ -283,7 +283,7 @@ public final class ExpressionParser<T> {
 			else
 				return 0;
 		}
-
+		
 		/**
 		 * @return priority
 		 * @since 2019-03-22
@@ -293,7 +293,7 @@ public final class ExpressionParser<T> {
 			return this.priority;
 		}
 	}
-
+	
 	/**
 	 * A binary operator with a priority field that determines which operators
 	 * apply first.
@@ -303,8 +303,8 @@ public final class ExpressionParser<T> {
 	 * @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>> {
+	private static abstract class PriorityBinaryOperator<T>
+			implements BinaryOperator<T>, Comparable<PriorityBinaryOperator<T>> {
 		/**
 		 * The operator's priority. Higher-priority operators are applied before
 		 * lower-priority operators
@@ -313,7 +313,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final int priority;
-
+		
 		/**
 		 * Creates the {@code PriorityBinaryOperator}.
 		 * 
@@ -321,10 +321,10 @@ public final class ExpressionParser<T> {
 		 * @since 2019-03-17
 		 * @since v0.2.0
 		 */
-		public PriorityBiFunction(final int priority) {
+		public PriorityBinaryOperator(final int priority) {
 			this.priority = priority;
 		}
-
+		
 		/**
 		 * Compares this object to another by priority.
 		 * 
@@ -336,7 +336,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		@Override
-		public int compareTo(final PriorityBiFunction<T, U, R> o) {
+		public int compareTo(final PriorityBinaryOperator<T> o) {
 			if (this.priority < o.priority)
 				return -1;
 			else if (this.priority > o.priority)
@@ -344,7 +344,7 @@ public final class ExpressionParser<T> {
 			else
 				return 0;
 		}
-
+		
 		/**
 		 * @return priority
 		 * @since 2019-03-22
@@ -354,7 +354,7 @@ public final class ExpressionParser<T> {
 			return this.priority;
 		}
 	}
-
+	
 	/**
 	 * A unary operator with a priority field that determines which operators
 	 * apply first.
@@ -374,7 +374,7 @@ public final class ExpressionParser<T> {
 		 * @since v0.2.0
 		 */
 		private final int priority;
-
+		
 		/**
 		 * Creates the {@code PriorityUnaryOperator}.
 		 * 
@@ -385,7 +385,7 @@ public final class ExpressionParser<T> {
 		public PriorityUnaryOperator(final int priority) {
 			this.priority = priority;
 		}
-
+		
 		/**
 		 * Compares this object to another by priority.
 		 * 
@@ -405,7 +405,7 @@ public final class ExpressionParser<T> {
 			else
 				return 0;
 		}
-
+		
 		/**
 		 * @return priority
 		 * @since 2019-03-22
@@ -415,7 +415,7 @@ public final class ExpressionParser<T> {
 			return this.priority;
 		}
 	}
-
+	
 	/**
 	 * The types of tokens that are available.
 	 * 
@@ -426,7 +426,7 @@ public final class ExpressionParser<T> {
 	private static enum TokenType {
 		OBJECT, UNARY_OPERATOR, BINARY_OPERATOR, NUMERIC_OPERATOR;
 	}
-
+	
 	/**
 	 * The opening bracket.
 	 * 
@@ -434,7 +434,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	public static final char OPENING_BRACKET = '(';
-
+	
 	/**
 	 * The closing bracket.
 	 * 
@@ -442,7 +442,7 @@ 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.
 	 * 
@@ -456,9 +456,9 @@ 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) {
@@ -475,16 +475,16 @@ 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) {
@@ -493,10 +493,10 @@ 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}.
@@ -505,7 +505,7 @@ 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.
 	 * 
@@ -513,7 +513,7 @@ 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.
@@ -522,7 +522,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final Map<String, PriorityBinaryOperator<T>> binaryOperators;
-
+	
 	/**
 	 * A map mapping operator strings to numeric functions.
 	 * 
@@ -530,7 +530,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.5.0
 	 */
 	private final Map<String, PriorityBiFunction<T, UncertainDouble, T>> numericOperators;
-
+	
 	/**
 	 * The operator for space, or null if spaces have no function.
 	 * 
@@ -538,7 +538,7 @@ public final class ExpressionParser<T> {
 	 * @since v0.2.0
 	 */
 	private final String spaceOperator;
-
+	
 	/**
 	 * Creates the {@code ExpressionParser}.
 	 * 
@@ -561,7 +561,7 @@ public final class ExpressionParser<T> {
 		this.numericOperators = numericOperators;
 		this.spaceOperator = spaceOperator;
 	}
-
+	
 	/**
 	 * Converts a given mathematical expression to reverse Polish notation
 	 * (operators after operands).
@@ -578,22 +578,21 @@ public final class ExpressionParser<T> {
 	 * @since 2019-03-17
 	 * @since v0.2.0
 	 */
-	// TODO revert to package private
-	public String convertExpressionToReversePolish(final String expression) {
+	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) != ' ') {
@@ -623,15 +622,15 @@ 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++) {
@@ -641,7 +640,7 @@ public final class ExpressionParser<T> {
 				}
 			}
 		}
-
+		
 		// turn the expression into reverse Polish
 		while (true) {
 			final int highestPriorityOperatorPosition = this
@@ -649,7 +648,7 @@ 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 -
@@ -684,16 +683,15 @@ 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
-		if (components.size() != 1) {
+		if (components.size() != 1)
 			throw new IllegalArgumentException(
 					"Invalid expression \"" + expression + "\".");
-		}
 		return components.get(0).replaceAll(" +", " ").trim();
 	}
-
+	
 	/**
 	 * Finds the position of the highest-priority operator in a list
 	 * 
@@ -711,18 +709,18 @@ 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;
@@ -732,7 +730,7 @@ 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;
@@ -742,7 +740,7 @@ public final class ExpressionParser<T> {
 				final PriorityBiFunction<T, UncertainDouble, T> numericOperator = this.numericOperators
 						.get(components.get(i));
 				final int numericPriority = numericOperator.getPriority();
-
+				
 				if (numericPriority > maxPriority) {
 					maxPriority = numericPriority;
 					maxPriorityPosition = i;
@@ -752,11 +750,11 @@ public final class ExpressionParser<T> {
 				break;
 			}
 		}
-
+		
 		// max priority position found
 		return maxPriorityPosition;
 	}
-
+	
 	/**
 	 * Determines whether an inputted string is an object or an operator
 	 * 
@@ -768,7 +766,7 @@ 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))
@@ -778,7 +776,7 @@ public final class ExpressionParser<T> {
 		else
 			return TokenType.OBJECT;
 	}
-
+	
 	/**
 	 * Parses an expression.
 	 * 
@@ -792,7 +790,7 @@ public final class ExpressionParser<T> {
 		return this.parseReversePolishExpression(
 				this.convertExpressionToReversePolish(expression));
 	}
-
+	
 	/**
 	 * Parses an expression expressed in reverse Polish notation.
 	 * 
@@ -804,43 +802,43 @@ 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(o2, o1));
 				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
 				// these try-catch statements are necessary
@@ -849,41 +847,41 @@ public final class ExpressionParser<T> {
 				// 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) {
+				} catch (final Exception e) {
 					try {
 						doubleStack.push(UncertainDouble.fromString(item));
-					} catch (IllegalArgumentException e2) {
+					} catch (final IllegalArgumentException e2) {
 						try {
 							doubleStack.push(
 									UncertainDouble.of(Double.parseDouble(item), 0));
-						} catch (NumberFormatException e3) {
+						} catch (final 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(