Change to data interfaces, as well as prepare to rewrite parser

17 files changed, 282 insertions, 168 deletions

diff --git a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguagePragmaHandlers.java b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguagePragmaHandlers.java
index 420391e..fa16515 100644
--- a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguagePragmaHandlers.java
+++ b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguagePragmaHandlers.java
@@ -3,10 +3,10 @@ package bjc.dicelang.examples;
 import java.util.Map;
 import java.util.function.BiConsumer;
 
-import bjc.dicelang.ast.DiceASTExpression;
-import bjc.dicelang.ast.DiceASTInliner;
-import bjc.dicelang.ast.DiceASTParser;
 import bjc.dicelang.ast.nodes.IDiceASTNode;
+import bjc.dicelang.old.ast.DiceASTExpression;
+import bjc.dicelang.old.ast.DiceASTInliner;
+import bjc.dicelang.old.ast.DiceASTParser;
 import bjc.utils.funcdata.FunctionalMap;
 import bjc.utils.parserutils.AST;
 
diff --git a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageState.java b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageState.java
index 92e75e3..7db6ab3 100644
--- a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageState.java
+++ b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageState.java
@@ -2,8 +2,8 @@ package bjc.dicelang.examples;
 
 import java.util.Map;
 
-import bjc.dicelang.ast.DiceASTExpression;
-import bjc.dicelang.ast.DiceASTParser;
+import bjc.dicelang.old.ast.DiceASTExpression;
+import bjc.dicelang.old.ast.DiceASTParser;
 import bjc.utils.data.Pair;
 
 /**
diff --git a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageTest.java b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageTest.java
index 54f54ac..3c84657 100644
--- a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageTest.java
+++ b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceASTLanguageTest.java
@@ -6,19 +6,20 @@ import java.util.Scanner;
 import java.util.function.BiConsumer;
 
 import bjc.dicelang.IDiceExpression;
-import bjc.dicelang.ast.DiceASTDefinedChecker;
-import bjc.dicelang.ast.DiceASTExpression;
-import bjc.dicelang.ast.DiceASTInliner;
-import bjc.dicelang.ast.DiceASTParser;
-import bjc.dicelang.ast.DiceASTReferenceChecker;
 import bjc.dicelang.ast.nodes.IDiceASTNode;
 import bjc.dicelang.ast.optimization.DiceASTOptimizer;
+import bjc.dicelang.old.ast.DiceASTDefinedChecker;
+import bjc.dicelang.old.ast.DiceASTExpression;
+import bjc.dicelang.old.ast.DiceASTInliner;
+import bjc.dicelang.old.ast.DiceASTParser;
+import bjc.dicelang.old.ast.DiceASTReferenceChecker;
 
 import static bjc.dicelang.examples.DiceASTLanguagePragmaHandlers.*;
 
 import bjc.utils.data.GenHolder;
 import bjc.utils.data.IHolder;
 import bjc.utils.funcdata.FunctionalMap;
+import bjc.utils.funcdata.IFunctionalMap;
 import bjc.utils.funcdata.bst.ITreePart.TreeLinearizationMethod;
 import bjc.utils.parserutils.AST;
 
@@ -149,20 +150,21 @@ public class DiceASTLanguageTest {
 
 		try {
 			numberOfRolls = Integer.parseInt(args[2]);
-		} catch (NumberFormatException nfex) {
+		} catch (@SuppressWarnings("unused") NumberFormatException nfex) {
+			// Don't care about details
 			System.err.println(
 					"ERROR: The second argument must be a valid number, and "
 							+ args[2] + " is not one.");
 			return;
 		}
 
-		IDiceExpression expressionToRoll =
-				languageState.merge((astParser, enviroment) -> {
+		IDiceExpression expressionToRoll = languageState
+				.merge((astParser, enviroment) -> {
 					if (!enviroment.containsKey(expressionName)) {
 						return null;
-					} else {
-						return enviroment.get(expressionName);
 					}
+
+					return enviroment.get(expressionName);
 				});
 
 		if (expressionToRoll == null) {
@@ -198,8 +200,8 @@ public class DiceASTLanguageTest {
 		// The parser to turn strings into AST's
 		DiceASTParser astParser = new DiceASTParser();
 
-		DiceASTLanguageState languageState =
-				new DiceASTLanguageState(astParser, enviroment);
+		DiceASTLanguageState languageState = new DiceASTLanguageState(
+				astParser, enviroment);
 
 		while (!currentLine.equalsIgnoreCase("quit")) {
 			String prospectiveCommandName = currentLine.split(" ")[0];
@@ -214,20 +216,20 @@ public class DiceASTLanguageTest {
 				AST<IDiceASTNode> builtAST;
 
 				try {
-					builtAST = astParser.buildAST(currentLine);
+					builtAST = DiceASTParser.buildAST(currentLine);
 				} catch (IllegalStateException isex) {
 					System.out.println(
 							"ERROR: " + isex.getLocalizedMessage());
 
-					currentLine =
-							getNextCommand(inputSource, commandNumber);
+					currentLine = getNextCommand(inputSource,
+							commandNumber);
 
 					continue;
 				}
 
 				// Build a rollable expression from the AST
-				DiceASTExpression expression =
-						new DiceASTExpression(builtAST, enviroment);
+				DiceASTExpression expression = new DiceASTExpression(
+						builtAST, enviroment);
 
 				int sampleRoll;
 
@@ -237,8 +239,8 @@ public class DiceASTLanguageTest {
 					System.out.println(
 							"ERROR: " + usex.getLocalizedMessage());
 
-					currentLine =
-							getNextCommand(inputSource, commandNumber);
+					currentLine = getNextCommand(inputSource,
+							commandNumber);
 
 					continue;
 				}
@@ -249,8 +251,8 @@ public class DiceASTLanguageTest {
 									+ " Problematic expression: \n\t"
 									+ expression);
 
-					currentLine =
-							getNextCommand(inputSource, commandNumber);
+					currentLine = getNextCommand(inputSource,
+							commandNumber);
 
 					continue;
 				}
@@ -320,9 +322,8 @@ public class DiceASTLanguageTest {
 	private static DiceASTExpression freezeOutLast(
 			Map<String, DiceASTExpression> enviroment,
 			AST<IDiceASTNode> builtAST) {
-		FunctionalMap<String, AST<IDiceASTNode>> transformedEnviroment =
-				new FunctionalMap<>(enviroment)
-						.mapValues((expr) -> expr.getAst());
+		IFunctionalMap<String, AST<IDiceASTNode>> transformedEnviroment = new FunctionalMap<>(
+				enviroment).mapValues((expr) -> expr.getAst());
 
 		AST<IDiceASTNode> expressionSansLast = DiceASTInliner
 				.selectiveInline(builtAST, transformedEnviroment, "last");
diff --git a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceExpressionParserTest.java b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceExpressionParserTest.java
index d2f947a..ceb90ef 100644
--- a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceExpressionParserTest.java
+++ b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceExpressionParserTest.java
@@ -44,7 +44,8 @@ public class DiceExpressionParserTest {
 		 */
 		DiceExpressionParser dep = new DiceExpressionParser();
 
-		IDiceExpression dexp = dep.parse(exp, new HashMap<>());
+		IDiceExpression dexp = DiceExpressionParser.parse(exp,
+				new HashMap<>());
 
 		/*
 		 * Roll the dice a specified amount of times
diff --git a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceLanguageTest.java b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceLanguageTest.java
index c832d6b..8dfaceb 100644
--- a/dice-lang/src/examples/java/bjc/dicelang/examples/DiceLanguageTest.java
+++ b/dice-lang/src/examples/java/bjc/dicelang/examples/DiceLanguageTest.java
@@ -76,7 +76,7 @@ public class DiceLanguageTest {
 			if (acts.containsKey(header)) {
 				acts.get(header).accept(ln, state);
 			} else {
-				IDiceExpression exp = dep.parse(ln, env);
+				IDiceExpression exp = DiceExpressionParser.parse(ln, env);
 
 				System.out.println("\tParsed: " + exp.toString());
 				System.out.println("\tSample Roll: " + exp.roll());
diff --git a/dice-lang/src/main/java/bjc/dicelang/DiceExpressionParser.java b/dice-lang/src/main/java/bjc/dicelang/DiceExpressionParser.java
index 05e8942..8a8ded3 100644
--- a/dice-lang/src/main/java/bjc/dicelang/DiceExpressionParser.java
+++ b/dice-lang/src/main/java/bjc/dicelang/DiceExpressionParser.java
@@ -5,8 +5,8 @@ import java.util.Stack;
 
 import org.apache.commons.lang3.StringUtils;
 
-import bjc.utils.funcdata.FunctionalList;
 import bjc.utils.funcdata.FunctionalStringTokenizer;
+import bjc.utils.funcdata.IFunctionalList;
 import bjc.utils.parserutils.ShuntingYard;
 
 /**
@@ -25,7 +25,7 @@ public class DiceExpressionParser {
 	 *            The enviroment to use when parsing expressions
 	 * @return The parsed dice expression
 	 */
-	public IDiceExpression parse(String exp,
+	public static IDiceExpression parse(String exp,
 			Map<String, IDiceExpression> env) {
 		/*
 		 * Create a tokenizer over the strings
@@ -50,8 +50,8 @@ public class DiceExpressionParser {
 		/*
 		 * Shunt the expression to postfix form
 		 */
-		FunctionalList<String> ls =
-				yard.postfix(fst.toList(s -> s), s -> s);
+		IFunctionalList<String> ls = yard.postfix(fst.toList(s -> s),
+				s -> s);
 
 		/*
 		 * Create a stack for building an expression from parts
@@ -82,8 +82,8 @@ public class DiceExpressionParser {
 					 * Handle scalar numbers
 					 */
 					dexps.push(new ScalarDie(Integer.parseInt(tok)));
-				} catch (NumberFormatException nfex) {
-
+				} catch (@SuppressWarnings("unused") NumberFormatException nfex) {
+					// We don't care about details, just that it failed
 					if (dexps.size() >= 2) {
 						/*
 						 * Apply an operation to two dice
diff --git a/dice-lang/src/main/java/bjc/dicelang/PolyhedralDice.java b/dice-lang/src/main/java/bjc/dicelang/PolyhedralDice.java
index e0bef64..9f609b4 100644
--- a/dice-lang/src/main/java/bjc/dicelang/PolyhedralDice.java
+++ b/dice-lang/src/main/java/bjc/dicelang/PolyhedralDice.java
@@ -19,6 +19,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d10
+	 * 
+	 * @return A single d10
+	 */
+	public static IDiceExpression d10() {
+		return d10(1);
+	}
+
+	/**
 	 * Produce the specified number of 100-sided dice
 	 * 
 	 * @param nDice
@@ -30,6 +39,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d100
+	 * 
+	 * @return A single d100
+	 */
+	public static IDiceExpression d100() {
+		return d100(1);
+	}
+
+	/**
 	 * Produce the specified number of 12-sided dice
 	 * 
 	 * @param nDice
@@ -41,6 +59,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d12
+	 * 
+	 * @return A single d12
+	 */
+	public static IDiceExpression d12() {
+		return d12(1);
+	}
+
+	/**
 	 * Produce the specified number of 20-sided dice
 	 * 
 	 * @param nDice
@@ -52,6 +79,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d20
+	 * 
+	 * @return A single d20
+	 */
+	public static IDiceExpression d20() {
+		return d20(1);
+	}
+
+	/**
 	 * Produce the specified number of 4-sided dice
 	 * 
 	 * @param nDice
@@ -63,6 +99,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d4
+	 * 
+	 * @return A single d4
+	 */
+	public static IDiceExpression d4() {
+		return d4(1);
+	}
+
+	/**
 	 * Produce the specified number of 6-sided dice
 	 * 
 	 * @param nDice
@@ -74,6 +119,15 @@ public class PolyhedralDice {
 	}
 
 	/**
+	 * Produce a single d6
+	 * 
+	 * @return A single d6
+	 */
+	public static IDiceExpression d6() {
+		return d6(1);
+	}
+
+	/**
 	 * Produce the specified number of 8-sided dice
 	 * 
 	 * @param nDice
@@ -83,4 +137,13 @@ public class PolyhedralDice {
 	public static IDiceExpression d8(int nDice) {
 		return new ComplexDice(nDice, 8);
 	}
+
+	/**
+	 * Produce a single d8
+	 * 
+	 * @return A single d8
+	 */
+	public static IDiceExpression d8() {
+		return d8(1);
+	}
 }
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/nodes/LiteralDiceNode.java b/dice-lang/src/main/java/bjc/dicelang/ast/nodes/LiteralDiceNode.java
index e689c7f..1a6d2bf 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/nodes/LiteralDiceNode.java
+++ b/dice-lang/src/main/java/bjc/dicelang/ast/nodes/LiteralDiceNode.java
@@ -38,7 +38,9 @@ public class LiteralDiceNode implements IDiceASTNode {
 
 	/**
 	 * Create a new node with the given value
-	 * @param val The value for this node
+	 * 
+	 * @param val
+	 *            The value for this node
 	 */
 	public LiteralDiceNode(int val) {
 		this(Integer.toString(val));
@@ -126,8 +128,12 @@ public class LiteralDiceNode implements IDiceASTNode {
 			try {
 				return new ScalarDie(Integer.parseInt(literalData));
 			} catch (NumberFormatException nfex) {
-				throw new UnsupportedOperationException(
+				UnsupportedOperationException usex = new UnsupportedOperationException(
 						"Found malformed leaf token " + this);
+
+				usex.initCause(nfex);
+
+				throw usex;
 			}
 		}
 	}
@@ -165,7 +171,8 @@ public class LiteralDiceNode implements IDiceASTNode {
 		try {
 			Integer.parseInt(value);
 			return true;
-		} catch (NumberFormatException nfex) {
+		} catch (@SuppressWarnings("unused") NumberFormatException nfex) {
+			// We don't care about details
 			return false;
 		}
 	}
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/nodes/OperatorDiceNode.java b/dice-lang/src/main/java/bjc/dicelang/ast/nodes/OperatorDiceNode.java
index e1eb316..2820cfb 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/nodes/OperatorDiceNode.java
+++ b/dice-lang/src/main/java/bjc/dicelang/ast/nodes/OperatorDiceNode.java
@@ -38,7 +38,11 @@ public enum OperatorDiceNode implements IDiceASTNode {
 	/**
 	 * Represents subtracting two nodes
 	 */
-	SUBTRACT;
+	SUBTRACT,
+	/**
+	 * Represents executing one statement in the context of the other
+	 */
+	LET;
 
 	/**
 	 * Create a operator node from a string
@@ -63,6 +67,8 @@ public enum OperatorDiceNode implements IDiceASTNode {
 				return GROUP;
 			case "c":
 				return COMPOUND;
+			case "->":
+				return LET;
 			default:
 				throw new IllegalArgumentException(
 						s + " is not a valid operator node");
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/optimization/DiceASTOptimizer.java b/dice-lang/src/main/java/bjc/dicelang/ast/optimization/DiceASTOptimizer.java
index e6c62ee..f6be7ab 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/optimization/DiceASTOptimizer.java
+++ b/dice-lang/src/main/java/bjc/dicelang/ast/optimization/DiceASTOptimizer.java
@@ -36,26 +36,26 @@ public class DiceASTOptimizer {
 		@Override
 		public AST<IDiceASTNode> apply(AST<IDiceASTNode> leftAST,
 				AST<IDiceASTNode> rightAST) {
-			AST<IDiceASTNode> rightBranchOfLeftAST =
-					leftAST.applyToRight((rightSideAST) -> rightSideAST);
-			AST<IDiceASTNode> leftBranchOfLeftAST =
-					leftAST.applyToRight((rightSideAST) -> rightSideAST);
+			AST<IDiceASTNode> rightBranchOfLeftAST = leftAST
+					.applyToRight((rightSideAST) -> rightSideAST);
+			AST<IDiceASTNode> leftBranchOfLeftAST = leftAST
+					.applyToRight((rightSideAST) -> rightSideAST);
 
 			boolean leftContainsNestedConstant = DiceASTOptimizer
 					.checkNodeType(rightBranchOfLeftAST, LITERAL)
 					&& DiceASTOptimizer.isNodeConstant(leftAST);
 
-			boolean isRightConstant =
-					DiceASTOptimizer.checkNodeType(rightAST, LITERAL)
-							&& DiceASTOptimizer.isNodeConstant(leftAST);
+			boolean isRightConstant = DiceASTOptimizer
+					.checkNodeType(rightAST, LITERAL)
+					&& DiceASTOptimizer.isNodeConstant(leftAST);
 
 			if (leftContainsNestedConstant && isRightConstant) {
 				int combinedValue = valueCollapser.apply(
 						getNodeValue(rightBranchOfLeftAST),
 						getNodeValue(rightAST));
 
-				AST<IDiceASTNode> newRightBranch =
-						new AST<>(new LiteralDiceNode(combinedValue));
+				AST<IDiceASTNode> newRightBranch = new AST<>(
+						new LiteralDiceNode(combinedValue));
 
 				return new AST<>(type, leftBranchOfLeftAST,
 						newRightBranch);
@@ -82,13 +82,13 @@ public class DiceASTOptimizer {
 		@Override
 		public AST<IDiceASTNode> apply(AST<IDiceASTNode> leftAST,
 				AST<IDiceASTNode> rightAST) {
-			boolean isLeftConstant =
-					DiceASTOptimizer.checkNodeType(leftAST, LITERAL)
-							&& DiceASTOptimizer.isNodeConstant(leftAST);
+			boolean isLeftConstant = DiceASTOptimizer
+					.checkNodeType(leftAST, LITERAL)
+					&& DiceASTOptimizer.isNodeConstant(leftAST);
 
-			boolean isRightConstant =
-					DiceASTOptimizer.checkNodeType(rightAST, LITERAL)
-							&& DiceASTOptimizer.isNodeConstant(leftAST);
+			boolean isRightConstant = DiceASTOptimizer
+					.checkNodeType(rightAST, LITERAL)
+					&& DiceASTOptimizer.isNodeConstant(leftAST);
 
 			if (isLeftConstant) {
 				if (isRightConstant) {
@@ -107,10 +107,8 @@ public class DiceASTOptimizer {
 		}
 	}
 
-	private static Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>>
-			buildConstantCollapsers() {
-		Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> operatorCollapsers =
-				new HashMap<>();
+	private static Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> buildConstantCollapsers() {
+		Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> operatorCollapsers = new HashMap<>();
 
 		operatorCollapsers.put(OperatorDiceNode.ADD,
 				new ArithmeticOperationCollapser(OperatorDiceNode.ADD,
@@ -131,10 +129,8 @@ public class DiceASTOptimizer {
 		return operatorCollapsers;
 	}
 
-	private static Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>>
-			buildNestedConstantCollapsers() {
-		Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> operatorCollapsers =
-				new HashMap<>();
+	private static Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> buildNestedConstantCollapsers() {
+		Map<IDiceASTNode, BinaryOperator<AST<IDiceASTNode>>> operatorCollapsers = new HashMap<>();
 
 		operatorCollapsers.put(OperatorDiceNode.ADD,
 				new NestedArithmeticOperationCollapser(
@@ -167,9 +163,9 @@ public class DiceASTOptimizer {
 			IDiceExpression leaf) {
 		if (leaf.canOptimize()) {
 			return new LiteralDiceNode(Integer.toString(leaf.optimize()));
-		} else {
-			return node;
 		}
+
+		return node;
 	}
 
 	private static AST<IDiceASTNode> finishTree(AST<IDiceASTNode> tree) {
@@ -184,14 +180,13 @@ public class DiceASTOptimizer {
 	 * @return The optimized tree
 	 */
 	public static AST<IDiceASTNode> optimizeTree(AST<IDiceASTNode> tree) {
-		AST<IDiceASTNode> astWithConstantsFolded =
-				tree.collapse(DiceASTOptimizer::collapseLeaf,
-						buildConstantCollapsers()::get,
-						DiceASTOptimizer::finishTree);
+		AST<IDiceASTNode> astWithConstantsFolded = tree.collapse(
+				DiceASTOptimizer::collapseLeaf,
+				buildConstantCollapsers()::get,
+				DiceASTOptimizer::finishTree);
 
-		AST<IDiceASTNode> astWithNestedConstantsFolded =
-				astWithConstantsFolded.collapse(
-						DiceASTOptimizer::collapseLeaf,
+		AST<IDiceASTNode> astWithNestedConstantsFolded = astWithConstantsFolded
+				.collapse(DiceASTOptimizer::collapseLeaf,
 						buildNestedConstantCollapsers()::get,
 						DiceASTOptimizer::finishTree);
 
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTDefinedChecker.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTDefinedChecker.java
index c26098c..4a20a82 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTDefinedChecker.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTDefinedChecker.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.Map;
 import java.util.function.Consumer;
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTExpression.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTExpression.java
index 3552926..7651093 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTExpression.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTExpression.java
@@ -1,7 +1,8 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.function.BinaryOperator;
 import java.util.function.Function;
 
 import bjc.dicelang.ComplexDice;
@@ -24,6 +25,37 @@ import bjc.utils.parserutils.AST;
  *
  */
 public class DiceASTExpression implements IDiceExpression {
+	private static final class ArithmeticCollapser
+			implements IOperatorCollapser {
+		private OperatorDiceNode		type;
+
+		private BinaryOperator<Integer>	valueOp;
+
+		public ArithmeticCollapser(OperatorDiceNode type,
+				BinaryOperator<Integer> valueOp) {
+			this.type = type;
+			this.valueOp = valueOp;
+		}
+
+		@Override
+		public Pair<Integer, AST<IDiceASTNode>> apply(
+				Pair<Integer, AST<IDiceASTNode>> leftNode,
+				Pair<Integer, AST<IDiceASTNode>> rightNode) {
+			return leftNode.merge((leftValue, leftAST) -> {
+				return rightNode.merge((rightValue, rightAST) -> {
+					if (type == OperatorDiceNode.DIVIDE
+							&& rightValue == 0) {
+						throw new ArithmeticException(
+								"Attempted to divide by zero. The AST of the problem expression is "
+										+ rightAST);
+					}
+
+					return new Pair<>(valueOp.apply(leftValue, rightValue),
+							new AST<>(type, leftAST, rightAST));
+				});
+			});
+		}
+	}
 
 	private static final class VariableRetriever
 			implements Function<IDiceASTNode, String> {
@@ -47,59 +79,26 @@ public class DiceASTExpression implements IDiceExpression {
 	 *            The enviroment to evaluate bindings and such against
 	 * @return The operations to use when collapsing the AST
 	 */
-	private static Map<IDiceASTNode, IOperatorCollapser> buildOperations(
-			Map<String, DiceASTExpression> enviroment) {
-		Map<IDiceASTNode, IOperatorCollapser> operatorCollapsers = new HashMap<>();
+	private static Map<IDiceASTNode, IOperatorCollapser>
+			buildOperations(Map<String, DiceASTExpression> enviroment) {
+		Map<IDiceASTNode, IOperatorCollapser> operatorCollapsers =
+				new HashMap<>();
 
 		operatorCollapsers.put(OperatorDiceNode.ADD,
-				(leftNode, rightNode) -> {
-					return leftNode.merge((leftValue, leftAST) -> {
-						return rightNode.merge((rightValue, rightAST) -> {
-							return new Pair<>(leftValue + rightValue,
-									new AST<>(OperatorDiceNode.ADD,
-											leftAST, rightAST));
-						});
-					});
+				new ArithmeticCollapser(OperatorDiceNode.ADD,
+						(left, right) -> left + right));
 
-				});
 		operatorCollapsers.put(OperatorDiceNode.SUBTRACT,
-				(leftNode, rightNode) -> {
-					return leftNode.merge((leftValue, leftAST) -> {
-						return rightNode.merge((rightValue, rightAST) -> {
-							return new Pair<>(leftValue - rightValue,
-									new AST<>(OperatorDiceNode.SUBTRACT,
-											leftAST, rightAST));
-						});
-					});
-				});
+				new ArithmeticCollapser(OperatorDiceNode.SUBTRACT,
+						(left, right) -> left - right));
 
 		operatorCollapsers.put(OperatorDiceNode.MULTIPLY,
-				(leftNode, rightNode) -> {
-					return leftNode.merge((leftValue, leftAST) -> {
-						return rightNode.merge((rightValue, rightAST) -> {
-							return new Pair<>(leftValue * rightValue,
-									new AST<>(OperatorDiceNode.MULTIPLY,
-											leftAST, rightAST));
-						});
-					});
+				new ArithmeticCollapser(OperatorDiceNode.MULTIPLY,
+						(left, right) -> left * right));
 
-				});
 		operatorCollapsers.put(OperatorDiceNode.DIVIDE,
-				(leftNode, rightNode) -> {
-					return leftNode.merge((leftValue, leftAST) -> {
-						return rightNode.merge((rightValue, rightAST) -> {
-							if (rightValue == 0) {
-								throw new ArithmeticException(
-										"Attempted to divide by zero. The AST of the problem expression is "
-												+ rightAST);
-							}
-
-							return new Pair<>(leftValue / rightValue,
-									new AST<>(OperatorDiceNode.DIVIDE,
-											leftAST, rightAST));
-						});
-					});
-				});
+				new ArithmeticCollapser(OperatorDiceNode.DIVIDE,
+						(left, right) -> left / right));
 
 		operatorCollapsers.put(OperatorDiceNode.ASSIGN, (left, right) -> {
 			return parseBinding(enviroment, left, right);
@@ -111,9 +110,46 @@ public class DiceASTExpression implements IDiceExpression {
 		operatorCollapsers.put(OperatorDiceNode.GROUP,
 				DiceASTExpression::parseGroup);
 
+		operatorCollapsers.put(OperatorDiceNode.LET, (left, right) -> {
+			return doLet(enviroment, left, right);
+		});
+
 		return operatorCollapsers;
 	}
 
+	private static Pair<Integer, AST<IDiceASTNode>> doLet(
+			Map<String, DiceASTExpression> enviroment,
+			Pair<Integer, AST<IDiceASTNode>> left,
+			Pair<Integer, AST<IDiceASTNode>> right) {
+		return left.merge((leftValue, leftAST) -> {
+			return right.merge((rightValue, rightAST) -> {
+				if (!leftAST
+						.applyToHead(DiceASTExpression::isAssignNode)) {
+					// Just ignore the left block then
+					return new Pair<>(rightValue, rightAST);
+				} else {
+					// Left block has an assignment to handle
+					String varName = leftAST.applyToLeft((leftBranch) -> {
+						return getAssignmentVar(leftBranch);
+					});
+
+					return null;
+				}
+			});
+		});
+	}
+
+	private static String getAssignmentVar(AST<IDiceASTNode> leftBranch) {
+		return leftBranch.applyToHead((node) -> {
+			return ((VariableDiceNode) node).getVariable();
+		});
+	}
+
+	private static Boolean isAssignNode(IDiceASTNode node) {
+		return node.getType() == DiceASTType.OPERATOR
+				&& node == OperatorDiceNode.ASSIGN;
+	}
+
 	private static Pair<Integer, AST<IDiceASTNode>> parseBinding(
 			Map<String, DiceASTExpression> enviroment,
 			Pair<Integer, AST<IDiceASTNode>> left,
@@ -129,8 +165,9 @@ public class DiceASTExpression implements IDiceExpression {
 
 				GenHolder<Boolean> selfReference = new GenHolder<>(false);
 
-				DiceASTReferenceChecker refChecker = new DiceASTReferenceChecker(
-						selfReference, variableName);
+				DiceASTReferenceChecker refChecker =
+						new DiceASTReferenceChecker(selfReference,
+								variableName);
 
 				rightAST.traverse(TreeLinearizationMethod.PREORDER,
 						refChecker);
@@ -163,8 +200,8 @@ public class DiceASTExpression implements IDiceExpression {
 			Pair<Integer, AST<IDiceASTNode>> rightNode) {
 		return leftNode.merge((leftValue, leftAST) -> {
 			return rightNode.merge((rightValue, rightAST) -> {
-				int compoundValue = Integer
-						.parseInt(Integer.toString(leftValue)
+				int compoundValue =
+						Integer.parseInt(Integer.toString(leftValue)
 								+ Integer.toString(rightValue));
 
 				return new Pair<>(compoundValue, new AST<>(
@@ -190,8 +227,8 @@ public class DiceASTExpression implements IDiceExpression {
 									+ rightAST);
 				}
 
-				int rolledValue = new ComplexDice(leftValue, rightValue)
-						.roll();
+				int rolledValue =
+						new ComplexDice(leftValue, rightValue).roll();
 
 				return new Pair<>(rolledValue, new AST<>(
 						OperatorDiceNode.GROUP, leftAST, rightAST));
@@ -231,8 +268,8 @@ public class DiceASTExpression implements IDiceExpression {
 	 * @return A pair consisting of the token's value and the AST it
 	 *         represents
 	 */
-	private Pair<Integer, AST<IDiceASTNode>> evaluateLeaf(
-			IDiceASTNode leafNode) {
+	private Pair<Integer, AST<IDiceASTNode>>
+			evaluateLeaf(IDiceASTNode leafNode) {
 		if (leafNode.getType() == DiceASTType.VARIABLE) {
 			VariableDiceNode node = (VariableDiceNode) leafNode;
 
@@ -247,8 +284,8 @@ public class DiceASTExpression implements IDiceExpression {
 		}
 	}
 
-	private Pair<Integer, AST<IDiceASTNode>> parseVariable(
-			VariableDiceNode leafNode) {
+	private Pair<Integer, AST<IDiceASTNode>>
+			parseVariable(VariableDiceNode leafNode) {
 		String varName = leafNode.getVariable();
 
 		if (env.containsKey(varName)) {
@@ -276,8 +313,8 @@ public class DiceASTExpression implements IDiceExpression {
 	 */
 	@Override
 	public int roll() {
-		Map<IDiceASTNode, IOperatorCollapser> operations = buildOperations(
-				env);
+		Map<IDiceASTNode, IOperatorCollapser> operations =
+				buildOperations(env);
 
 		return ast.collapse(this::evaluateLeaf, operations::get,
 				(returnedValue) -> returnedValue
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTFlattener.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTFlattener.java
index a54a088..a7500a8 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTFlattener.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTFlattener.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.HashMap;
 import java.util.Map;
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTInliner.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTInliner.java
index ef4a904..3a8e796 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTInliner.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTInliner.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.function.Function;
 
@@ -7,6 +7,8 @@ import bjc.dicelang.ast.nodes.IDiceASTNode;
 import bjc.dicelang.ast.nodes.VariableDiceNode;
 import bjc.utils.funcdata.FunctionalList;
 import bjc.utils.funcdata.FunctionalMap;
+import bjc.utils.funcdata.IFunctionalList;
+import bjc.utils.funcdata.IFunctionalMap;
 import bjc.utils.parserutils.AST;
 
 /**
@@ -19,9 +21,9 @@ import bjc.utils.parserutils.AST;
 public class DiceASTInliner {
 	private static class NodeInliner
 			implements Function<IDiceASTNode, AST<IDiceASTNode>> {
-		private FunctionalMap<String, AST<IDiceASTNode>> enviroment;
+		private IFunctionalMap<String, AST<IDiceASTNode>> enviroment;
 
-		public NodeInliner(FunctionalMap<String, AST<IDiceASTNode>> env) {
+		public NodeInliner(IFunctionalMap<String, AST<IDiceASTNode>> env) {
 			enviroment = env;
 		}
 
@@ -29,13 +31,13 @@ public class DiceASTInliner {
 		public AST<IDiceASTNode> apply(IDiceASTNode nod) {
 			if (nod.getType() == DiceASTType.VARIABLE) {
 				return expandNode((VariableDiceNode) nod);
-			} else {
-				return new AST<>(nod);
 			}
+
+			return new AST<>(nod);
 		}
 
-		protected AST<IDiceASTNode>
-				expandNode(VariableDiceNode variableNode) {
+		protected AST<IDiceASTNode> expandNode(
+				VariableDiceNode variableNode) {
 			String varName = variableNode.getVariable();
 
 			if (!enviroment.containsKey(varName)) {
@@ -50,24 +52,24 @@ public class DiceASTInliner {
 
 	private static final class SelectiveInliner extends NodeInliner {
 
-		private FunctionalList<String> variableNames;
+		private IFunctionalList<String> variableNames;
 
 		public SelectiveInliner(
-				FunctionalMap<String, AST<IDiceASTNode>> env,
-				FunctionalList<String> varNames) {
+				IFunctionalMap<String, AST<IDiceASTNode>> env,
+				IFunctionalList<String> varNames) {
 			super(env);
 
 			variableNames = varNames;
 		}
 
 		@Override
-		protected AST<IDiceASTNode>
-				expandNode(VariableDiceNode variableNode) {
+		protected AST<IDiceASTNode> expandNode(
+				VariableDiceNode variableNode) {
 			if (variableNames.contains(variableNode.getVariable())) {
 				return super.expandNode(variableNode);
-			} else {
-				return new AST<>(variableNode);
 			}
+
+			return new AST<>(variableNode);
 		}
 	}
 
@@ -81,7 +83,7 @@ public class DiceASTInliner {
 	 * @return The tree with references inlined
 	 */
 	public static AST<IDiceASTNode> inlineAST(AST<IDiceASTNode> tree,
-			FunctionalMap<String, AST<IDiceASTNode>> env) {
+			IFunctionalMap<String, AST<IDiceASTNode>> env) {
 		return selectiveInline(tree, env);
 	}
 
@@ -112,7 +114,7 @@ public class DiceASTInliner {
 	 * @return An AST with the specified variables inlined
 	 */
 	public static AST<IDiceASTNode> selectiveInline(AST<IDiceASTNode> tree,
-			FunctionalMap<String, AST<IDiceASTNode>> env,
+			IFunctionalMap<String, AST<IDiceASTNode>> env,
 			String... varNames) {
 		return selectiveInline(tree, env, new FunctionalList<>(varNames));
 	}
@@ -129,8 +131,8 @@ public class DiceASTInliner {
 	 * @return An AST with the specified variables inline
 	 */
 	public static AST<IDiceASTNode> selectiveInline(AST<IDiceASTNode> tree,
-			FunctionalMap<String, AST<IDiceASTNode>> env,
-			FunctionalList<String> varNames) {
-		return tree.expand(new SelectiveInliner(env, varNames));
+			IFunctionalMap<String, AST<IDiceASTNode>> env,
+			IFunctionalList<String> varNames) {
+		return tree.flatMapTree(new SelectiveInliner(env, varNames));
 	}
 }
\ No newline at end of file
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTParser.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTParser.java
index fb77ad5..d8e13f7 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTParser.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTParser.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.Deque;
 import java.util.LinkedList;
@@ -10,9 +10,10 @@ import bjc.dicelang.ast.nodes.IDiceASTNode;
 import bjc.dicelang.ast.nodes.LiteralDiceNode;
 import bjc.dicelang.ast.nodes.OperatorDiceNode;
 import bjc.dicelang.ast.nodes.VariableDiceNode;
+import bjc.utils.data.IPair;
 import bjc.utils.data.Pair;
-import bjc.utils.funcdata.FunctionalList;
 import bjc.utils.funcdata.FunctionalStringTokenizer;
+import bjc.utils.funcdata.IFunctionalList;
 import bjc.utils.funcutils.ListUtils;
 import bjc.utils.parserutils.AST;
 import bjc.utils.parserutils.ShuntingYard;
@@ -56,7 +57,8 @@ public class DiceASTParser {
 				try {
 					Integer.parseInt(tok);
 					return true;
-				} catch (NumberFormatException nfx) {
+				} catch (@SuppressWarnings("unused") NumberFormatException nfex) {
+					// We don't care about details
 					return false;
 				}
 			}
@@ -86,11 +88,11 @@ public class DiceASTParser {
 	 *            The string to build from
 	 * @return An AST built from the passed in string
 	 */
-	public AST<IDiceASTNode> buildAST(String exp) {
-		FunctionalList<String> tokens =
-				FunctionalStringTokenizer.fromString(exp).toList();
+	public static AST<IDiceASTNode> buildAST(String exp) {
+		IFunctionalList<String> tokens = FunctionalStringTokenizer
+				.fromString(exp).toList();
 
-		Deque<Pair<String, String>> ops = new LinkedList<>();
+		Deque<IPair<String, String>> ops = new LinkedList<>();
 
 		ops.add(new Pair<>("+", "\\+"));
 		ops.add(new Pair<>("-", "-"));
@@ -98,19 +100,19 @@ public class DiceASTParser {
 		ops.add(new Pair<>("/", "/"));
 		ops.add(new Pair<>(":=", ":="));
 
-		FunctionalList<String> semiExpandedTokens =
-				ListUtils.splitTokens(tokens, ops);
+		IFunctionalList<String> semiExpandedTokens = ListUtils
+				.splitTokens(tokens, ops);
 
 		ops = new LinkedList<>();
 
 		ops.add(new Pair<>("(", "\\("));
 		ops.add(new Pair<>(")", "\\)"));
 
-		FunctionalList<String> fullyExpandedTokens =
-				ListUtils.deAffixTokens(semiExpandedTokens, ops);
+		IFunctionalList<String> fullyExpandedTokens = ListUtils
+				.deAffixTokens(semiExpandedTokens, ops);
 
-		FunctionalList<String> shunted =
-				yard.postfix(fullyExpandedTokens, (s) -> s);
+		IFunctionalList<String> shunted = yard.postfix(fullyExpandedTokens,
+				(s) -> s);
 
 		AST<String> rawAST = TreeConstructor.constructTree(shunted,
 				DiceASTParser::isOperator);
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTReferenceChecker.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTReferenceChecker.java
index 8fa4d55..e526ee9 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/DiceASTReferenceChecker.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/DiceASTReferenceChecker.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.function.Consumer;
 
diff --git a/dice-lang/src/main/java/bjc/dicelang/ast/IOperatorCollapser.java b/dice-lang/src/main/java/bjc/dicelang/old/ast/IOperatorCollapser.java
index c872583..65cb264 100644
--- a/dice-lang/src/main/java/bjc/dicelang/ast/IOperatorCollapser.java
+++ b/dice-lang/src/main/java/bjc/dicelang/old/ast/IOperatorCollapser.java
@@ -1,4 +1,4 @@
-package bjc.dicelang.ast;
+package bjc.dicelang.old.ast;
 
 import java.util.function.BinaryOperator;
 
@@ -14,5 +14,5 @@ import bjc.utils.parserutils.AST;
  */
 public interface IOperatorCollapser
 		extends BinaryOperator<Pair<Integer, AST<IDiceASTNode>>> {
-
+	// Just an alias
 }