1 files changed, 91 insertions, 0 deletions
diff --git a/dice-lang/src/bjc/dicelang/IDiceExpression.java b/dice-lang/src/bjc/dicelang/IDiceExpression.java
new file mode 100644
index 0000000..acb1d4d
--- /dev/null
+++ b/dice-lang/src/bjc/dicelang/IDiceExpression.java
@@ -0,0 +1,91 @@
+package bjc.dicelang;
+
+import bjc.utils.funcutils.StringUtils;
+
+/**
+ * An expression for something that can be rolled like a polyhedral die
+ * 
+ * @author ben
+ *
+ */
+@FunctionalInterface
+public interface IDiceExpression {
+	/**
+	 * Parse a string into an expression.
+	 * 
+	 * It can accept the following types of expressions
+	 * <ul>
+	 * <li>Simple integers - '2'</li>
+	 * <li>Simple dice - 'd6'</li>
+	 * <li>Groups of simple dice - '2d6'</li>
+	 * <li>Number concatenation - '2c6'</li>
+	 * <li>Dice concatenation - '1d10c1d10</li>
+	 * </ul>
+	 * 
+	 * Dice concatenation is like using 2 d10s to emulate a d100, so
+	 * instead of adding them, it reads them side by side.
+	 * 
+	 * @param expression
+	 *            The string to convert to an expression
+	 * 
+	 * @return The string, converted into expression form
+	 */
+	static IDiceExpression toExpression(String expression) {
+		String literalData = expression;
+
+		if (StringUtils.containsInfixOperator(literalData, "c")) {
+			// Parse a compound die
+			String[] strangs = literalData.split("c");
+
+			return new CompoundDice(strangs);
+		} else if (StringUtils.containsInfixOperator(literalData, "d")) {
+			// Handle groups of similiar dice
+			return ComplexDice.fromString(literalData);
+		} else if (literalData.matches("\\Ad\\d+\\Z")) {
+			// Handle people who put 'd6' instead of '1d6'
+			return new Die(Integer.parseInt(literalData.substring(1)));
+		} else {
+			// Parse a scalar number
+			try {
+				return new ScalarDie(Integer.parseInt(literalData));
+			} catch (NumberFormatException nfex) {
+				UnsupportedOperationException usex = new UnsupportedOperationException(
+						"Found malformed leaf token " + expression);
+
+				usex.initCause(nfex);
+
+				throw usex;
+			}
+		}
+	}
+
+	/**
+	 * Check if this expression can be optimized to a scalar value
+	 * 
+	 * @return Whether or not this expression can be optimized to a scalar
+	 *         value
+	 */
+	public default boolean canOptimize() {
+		return false;
+	}
+
+	/**
+	 * Optimize this expression to a scalar value
+	 * 
+	 * @return This expression, optimized to a scalar value
+	 * 
+	 * @throws UnsupportedOperationException
+	 *             if this type of expression can't be optimized
+	 */
+	public default int optimize() {
+		throw new UnsupportedOperationException(
+				"Can't optimize this type of expression");
+	}
+
+	/**
+	 * Roll the dice once
+	 * 
+	 * @return The result of rowing the dice
+	 */
+	public int roll();
+}
+\ No newline at end of file