1 files changed, 160 insertions, 0 deletions
diff --git a/dice-lang/src/bjc/dicelang/ast/DiceASTParser.java b/dice-lang/src/bjc/dicelang/ast/DiceASTParser.java
new file mode 100644
index 0000000..9a36951
--- /dev/null
+++ b/dice-lang/src/bjc/dicelang/ast/DiceASTParser.java
@@ -0,0 +1,160 @@
+package bjc.dicelang.ast;
+
+import java.util.Deque;
+import java.util.InputMismatchException;
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+import bjc.utils.funcdata.FunctionalList;
+import bjc.utils.funcdata.FunctionalMap;
+import bjc.utils.funcdata.IList;
+import bjc.utils.funcdata.IMap;
+import bjc.utils.funcdata.ITree;
+import bjc.utils.funcdata.Tree;
+import bjc.utils.funcutils.StringUtils;
+import bjc.utils.parserutils.TreeConstructor;
+
+import bjc.dicelang.IDiceExpression;
+import bjc.dicelang.ast.nodes.DiceLiteralNode;
+import bjc.dicelang.ast.nodes.DiceLiteralType;
+import bjc.dicelang.ast.nodes.IDiceASTNode;
+import bjc.dicelang.ast.nodes.ILiteralDiceNode;
+import bjc.dicelang.ast.nodes.IntegerLiteralNode;
+import bjc.dicelang.ast.nodes.OperatorDiceNode;
+import bjc.dicelang.ast.nodes.VariableDiceNode;
+
+/**
+ * Parse a string expression into AST form. Doesn't do anything else
+ * 
+ * @author ben
+ *
+ */
+public class DiceASTParser {
+	private static IDiceASTNode convertLeafNode(String leafNode) {
+		DiceLiteralType literalType = ILiteralDiceNode
+				.getLiteralType(leafNode);
+
+		if (literalType != null) {
+			switch (literalType) {
+				case DICE:
+					return new DiceLiteralNode(
+							IDiceExpression.toExpression(leafNode));
+				case INTEGER:
+					return new IntegerLiteralNode(
+							Integer.parseInt(leafNode));
+				default:
+					throw new InputMismatchException(
+							"Cannot convert string '" + leafNode
+									+ "' into a literal.");
+			}
+		}
+
+		if (leafNode.matches("[+-]?\\d*\\.\\d+")) {
+			throw new InputMismatchException(
+					"Floating point literals are not supported");
+		}
+
+		return new VariableDiceNode(leafNode);
+	}
+
+	private static IDiceASTNode convertOperatorNode(String operatorNode) {
+		try {
+			return OperatorDiceNode.fromString(operatorNode);
+		} catch (IllegalArgumentException iaex) {
+			InputMismatchException imex = new InputMismatchException(
+					"Attempted to parse invalid operator " + operatorNode);
+
+			imex.initCause(iaex);
+
+			throw imex;
+		}
+	}
+
+	/**
+	 * Create an AST from a list of tokens
+	 * 
+	 * @param tokens
+	 *            The list of tokens to convert
+	 * @return An AST built from the tokens
+	 */
+	public static ITree<IDiceASTNode> createFromString(
+			IList<String> tokens) {
+		Predicate<String> specialPicker = (operator) -> {
+			if (StringUtils.containsOnly(operator, "\\[")) {
+				return true;
+			} else if (StringUtils.containsOnly(operator, "\\]")) {
+				return true;
+			}
+
+			return false;
+		};
+
+		IMap<String, Function<Deque<ITree<String>>, ITree<String>>> operators = new FunctionalMap<>();
+
+		operators.put("[", (queuedTrees) -> {
+			Tree<String> openArray = new Tree<>("[");
+
+			return openArray;
+		});
+
+		operators.put("]", (queuedTrees) -> {
+			return parseCloseArray(queuedTrees);
+		});
+
+		ITree<String> rawTokens = TreeConstructor.constructTree(tokens,
+				(token) -> {
+					return isOperatorNode(token);
+				}, specialPicker, operators::get);
+
+		ITree<IDiceASTNode> tokenizedTree = rawTokens.rebuildTree(
+				DiceASTParser::convertLeafNode,
+				DiceASTParser::convertOperatorNode);
+
+		return tokenizedTree;
+	}
+
+	private static boolean isOperatorNode(String token) {
+		if (StringUtils.containsOnly(token, "\\[")) {
+			return true;
+		} else if (StringUtils.containsOnly(token, "\\]")) {
+			return true;
+		}
+
+		if (token.equals("[]")) {
+			// This is a synthetic operator, constructed by [ and ]
+			return true;
+		}
+
+		try {
+			OperatorDiceNode.fromString(token);
+			return true;
+		} catch (@SuppressWarnings("unused") IllegalArgumentException iaex) {
+			// We don't care about details
+			return false;
+		}
+	}
+
+	private static ITree<String> parseCloseArray(
+			Deque<ITree<String>> queuedTrees) {
+		IList<ITree<String>> children = new FunctionalList<>();
+
+		while (shouldContinuePopping(queuedTrees)) {
+			children.add(queuedTrees.pop());
+		}
+
+		queuedTrees.pop();
+
+		children.reverse();
+
+		ITree<String> arrayTree = new Tree<>("[]", children);
+
+		return arrayTree;
+	}
+
+	private static boolean shouldContinuePopping(
+			Deque<ITree<String>> queuedTrees) {
+		String peekToken = queuedTrees.peek().getHead();
+
+		return !peekToken.equals("[");
+	}
+}