Added dice roller

1 files changed, 57 insertions, 0 deletions

diff --git a/BJC-Utils2/src/main/java/bjc/utils/dice/DiceExpressionParser.java b/BJC-Utils2/src/main/java/bjc/utils/dice/DiceExpressionParser.java
new file mode 100644
index 0000000..3be56e4
--- /dev/null
+++ b/BJC-Utils2/src/main/java/bjc/utils/dice/DiceExpressionParser.java
@@ -0,0 +1,57 @@
+package bjc.utils.dice;
+
+import java.util.Stack;
+
+import bjc.utils.funcdata.FunctionalList;
+import bjc.utils.funcdata.FunctionalStringTokenizer;
+import bjc.utils.parserutils.ShuntingYard;
+
+public class DiceExpressionParser {
+	public DiceExpression parse(String exp) {
+		FunctionalStringTokenizer fst = new FunctionalStringTokenizer(exp);
+
+		ShuntingYard<String> yard = new ShuntingYard<>();
+
+		FunctionalList<String> ls = yard.postfix(fst.toList(s -> s),
+				s -> s);
+
+		Stack<DiceExpression> dexps = new Stack<>();
+
+		ls.forEach((tok) -> {
+			if (tok.contains("d")) {
+				dexps.push(Dice.fromString(tok));
+			} else {
+				try {
+					dexps.push(new ScalarDie(Integer.parseInt(tok)));
+				} catch (NumberFormatException nfex) {
+
+					DiceExpression l = dexps.pop();
+					DiceExpression r = dexps.pop();
+
+					switch (tok) {
+						case "+":
+							dexps.push(new CompoundDiceExpression(l, r,
+									DiceExpressionType.ADD));
+							break;
+						case "-":
+							dexps.push(new CompoundDiceExpression(l, r,
+									DiceExpressionType.SUBTRACT));
+							break;
+						case "*":
+							dexps.push(new CompoundDiceExpression(l, r,
+									DiceExpressionType.MULTIPLY));
+							break;
+						case "/":
+							dexps.push(new CompoundDiceExpression(l, r,
+									DiceExpressionType.DIVIDE));
+							break;
+						default:
+							throw new IllegalStateException("Detected invalid operator " + tok);
+					}
+				}
+			}
+		});
+
+		return dexps.pop();
+	}
+}