Adds a condition for is divisible by

src/main/java/ch/njol/skript/conditions/CondIsDivisibleBy.java

@@ -0,0 +1,60 @@
+package ch.njol.skript.conditions;
+
+import ch.njol.skript.Skript;
+import ch.njol.skript.doc.Description;
+import ch.njol.skript.doc.Examples;
+import ch.njol.skript.doc.Name;
+import ch.njol.skript.doc.Since;
+import ch.njol.skript.lang.Condition;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.util.Checker;
+import ch.njol.util.Kleenean;
+import org.bukkit.event.Event;
+import org.jetbrains.annotations.Nullable;
+
+@Name("Is Evenly Divisible By")
+@Description("Check if a number is evenly divisible by another number.")
+@Examples({
+	"if 5 is evenly divisible by 5:",
+	"if 11 cannot be evenly divided by 10:",
+})
+@Since("INSERT VERSION")
+public class CondIsDivisibleBy extends Condition {
+
+	static {
+		Skript.registerCondition(CondIsDivisibleBy.class,
+			"%numbers% (is|are) evenly divisible by %number%",
+			"%numbers% (isn't|is not|aren't|are not) evenly divisible by %number%",
+			"%numbers% can be evenly divided by %number%",
+			"%numbers% (can't|can[ ]not) be evenly divided by %number%");
+	}
+	@SuppressWarnings("null")
+	private Expression<Number> dividend;
+	@SuppressWarnings("null")
+	private Expression<Number> divisor;
+
+	@Override
+	public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, ParseResult parseResult) {
+		dividend = (Expression<Number>) exprs[0];
+		divisor = (Expression<Number>) exprs[1];
+		setNegated(matchedPattern == 1 || matchedPattern == 3);
+		return true;
+	}
+
+	@Override
+	public boolean check(Event event) {
+		Number divisorNumber = divisor.getSingle(event);
+		if (divisorNumber == null)
+			return isNegated();
+		double divisor = divisorNumber.doubleValue();
+		return dividend.check(event, dividendNumber -> (dividendNumber.doubleValue() % divisor == 0), isNegated());
+	}
+
+	@Override
+	public String toString(@Nullable Event event, boolean debug) {
+		return dividend.toString(event, debug) + " is " + (isNegated() ? "not " : "")
+			+ "evenly divisible by " + divisor.toString(event, debug);
+	}
+
+}

src/test/skript/tests/syntaxes/conditions/CondIsDivisibleBy.sk

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+test "is divisible":
+	assert 5 can be evenly divided by 5 with "5 can be divided by 5!"
+	assert 5 can not be evenly divided by 10 with "5 cannot be divided by 10!"
+	assert 5 isn't evenly divisible by 0 with "nothing can be divided by 0!"
+	assert 1964903306 is evenly divisible by 982451653 with "1964903306 is divisible by 982451653!"
+	assert {_none} is evenly divisible by 10 to fail with "you cannot divide by <none>!"
+	assert 5, 10, and 15 can be evenly divided by 5 with "5, 10, and 15 can be evenly divided by 5!"
+	assert 3, 5, and 7 cannot be evenly divided by 2 with "3, 5, and 7 cannot be evenly divided by 2!"
+	assert 5 or 10 or 15 can be evenly divided by 5 with "5 or 10 or 15 can be evenly divided by 5!"
+	assert 3 or 5 or 7 cannot be evenly divided by 2 with "3 or 5 or 7 cannot be evenly divided by 2!"