1 files changed, 142 insertions, 0 deletions
diff --git a/dice-lang/src/bjc/dicelang/v2/dice/DiceBox.java b/dice-lang/src/bjc/dicelang/v2/dice/DiceBox.java
new file mode 100644
index 0000000..995c3bf
--- /dev/null
+++ b/dice-lang/src/bjc/dicelang/v2/dice/DiceBox.java
@@ -0,0 +1,142 @@
+package bjc.dicelang.v2.dice;
+
+import java.util.Random;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+public class DiceBox {
+	static final Random rng = new Random();
+
+	public static DieExpression parseExpression(String exp) {
+		if(!isValidExpression(exp)) return null;
+
+		if(scalarDiePattern.matcher(exp).matches()) {
+			Die scal = new ScalarDie(Long.parseLong(exp.substring(0, exp.indexOf('s'))));
+
+			return new DieExpression(scal);
+		} else if(simpleDiePattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("d");
+
+			long right = Long.parseLong(dieParts[1]);
+			if(dieParts[0].equals("")) {
+				Die scal = new SimpleDie(1, right);
+				return new DieExpression(scal);
+			} else {
+				Die scal = new SimpleDie(Long.parseLong(dieParts[0]), right);
+				return new DieExpression(scal);
+			}
+		} else if(fudgeDiePattern.matcher(exp).matches()) {
+			String nDice = exp.substring(0, exp.indexOf('d'));
+
+			return new DieExpression(new FudgeDie(Long.parseLong(nDice)));
+		} else if(compoundDiePattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("c");
+
+			DieExpression left  = parseExpression(dieParts[0]);
+			DieExpression right = parseExpression(dieParts[1]);
+
+			return new DieExpression(new CompoundDie(left.scalar, right.scalar));
+		} else if(compoundingDiePattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("!!");
+
+			DieExpression   left  = parseExpression(dieParts[0]);
+			Predicate<Long> right = deriveCond(dieParts[1]);
+
+			Die scal = new CompoundingDie(left.scalar, right, dieParts[1]);
+			return new DieExpression(scal);
+		} else if(explodingDiePattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("!");
+
+			DieExpression   left  = parseExpression(dieParts[0]);
+			Predicate<Long> right = deriveCond(dieParts[1]);
+
+			DieList lst = new ExplodingDice(left.scalar, right, dieParts[1], false);
+			return new DieExpression(lst);
+		} else if(penetratingDiePattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("p!");
+
+			DieExpression   left  = parseExpression(dieParts[0]);
+			Predicate<Long> right = deriveCond(dieParts[1]);
+
+			DieList lst = new ExplodingDice(left.scalar, right, dieParts[1], true);
+			return new DieExpression(lst);
+		} else if(diceListPattern.matcher(exp).matches()) {
+			String[] dieParts = exp.split("dl");
+
+			DieExpression left  = parseExpression(dieParts[0]);
+			DieExpression right = parseExpression(dieParts[1]);
+			
+			DieList lst = new SimpleDieList(left.scalar, right.scalar);
+			return new DieExpression(lst);
+		}
+
+		// @TODO give a specific error message
+		return null;
+	}
+
+	private static final String comparePoint         = "[<>=]\\d+";
+
+	private static final String  scalarDie          = "[\\+\\-]?\\d+sd";
+	private static final Pattern scalarDiePattern   = Pattern.compile("\\A" + scalarDie + "\\Z");
+
+	private static final String  simpleDie           = "(?:\\d+)?d\\d+";
+	private static final Pattern simpleDiePattern    = Pattern.compile("\\A" + simpleDie + "\\Z");
+
+	private static final String  fudgeDie            = "(?:\\d+)?dF";
+	private static final Pattern fudgeDiePattern     = Pattern.compile("\\A" + fudgeDie + "\\Z");
+
+	private static final String  compoundDie         = simpleDie + "c(?:(?:" + simpleDie + ")|(?:\\d+))";
+	private static final Pattern compoundDiePattern  = Pattern.compile("\\A" + compoundDie + "\\Z");
+
+	private static final String  compoundGroup       = "(?:(?:" + scalarDie + ")|(?:" + simpleDie + ")|(?:"
+		+ compoundDie + ")|(?:" + fudgeDie +"))";
+
+	private static final String  compoundingDie        = compoundGroup + "!!" + comparePoint;
+	private static final Pattern compoundingDiePattern = Pattern.compile("\\A" + compoundingDie + "\\Z");
+
+	private static final String  explodingDie        = compoundGroup + "!" + comparePoint;
+	private static final Pattern explodingDiePattern = Pattern.compile("\\A" + explodingDie + "\\Z");
+
+	private static final String  penetratingDie        = compoundGroup + "!" + comparePoint;
+	private static final Pattern penetratingDiePattern = Pattern.compile("\\A" + penetratingDie + "\\Z");
+
+	private static final String  diceList            = compoundGroup + "dl" + compoundGroup;
+	private static final Pattern diceListPattern     = Pattern.compile("\\A" + diceList + "\\Z");
+
+	public static boolean isValidExpression(String exp) {
+		if(scalarDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(simpleDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(fudgeDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(compoundDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(compoundingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(explodingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if(penetratingDiePattern.matcher(exp).matches()) {
+			return true;
+		} else if (diceListPattern.matcher(exp).matches()) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	private static Predicate<Long> deriveCond(String patt) {
+		long            num  = Long.parseLong(patt.substring(1));
+
+		switch(patt.charAt(0)) {
+		case '<':
+			return (roll) -> roll < num;
+		case '=':
+			return (roll) -> roll == num;
+		case '>':
+			return (roll) -> roll > num;
+		default:
+			return (roll) -> false;
+		}
+	}
+}