Add single-argument vector function overload (fixes #8265)

src/main/java/ch/njol/skript/classes/data/DefaultFunctions.java

@@ -492,6 +492,16 @@ public Date[] executeSimple(Object[][] params) {
 				args.<Number>get("z").doubleValue()
 			)));
 
+		Functions.register(DefaultFunction.builder(skript, "vector", Vector.class)
+			.description("Creates a new vector with all components equal to the given value. Equivalent to vector(n, n, n).")
+			.examples("vector(5) # same as vector(5, 5, 5)")
+			.since("INSERT VERSION")
+			.parameter("n", Number.class)
+			.build(args -> {
+				double value = args.<Number>get("n").doubleValue();
+				return new Vector(value, value, value);
+			}));
+
 		Functions.registerFunction(new SimpleJavaFunction<Long>("calcExperience", new Parameter[] {
 			new Parameter<>("level", DefaultClasses.LONG, true, null)
 		}, DefaultClasses.LONG, true) {

src/main/java/ch/njol/skript/lang/function/Functions.java

@@ -68,7 +68,9 @@ public static DefaultFunction<?> register(DefaultFunction<?> function) {
 		if (!name.matches(functionNamePattern))
 			throw new SkriptAPIException("Invalid function name '%s'".formatted(name));
 
-		javaNamespace.addSignature((Signature<?>) function.signature());
+		if (javaNamespace.getSignature(name) == null) {
+			javaNamespace.addSignature((Signature<?>) function.signature());
+		}
 		javaNamespace.addFunction((Function<?>) function);
 		globalFunctions.put(function.name(), javaNamespace);
 

src/test/skript/tests/syntaxes/expressions/ExprVectorFromXYZ.sk

@@ -9,3 +9,16 @@ test "vector from xyz":
 	set {_random} to a random vector
 	set {_vector} to a new vector from x component of {_random}, y component of {_random}, z component of {_random}
 	assert {_vector} is {_random} with "random vector to created component equality failed (expected %{_random}%, got %{_vector}%)"
+
+test "vector single argument":
+	assert vector(5) is vector(5, 5, 5) with "single-argument vector(5) failed"
+	assert vector(0) is vector(0, 0, 0) with "single-argument vector(0) failed"
+	assert vector(-10) is vector(-10, -10, -10) with "single-argument vector(-10) failed"
+	assert vector(3.14) is vector(3.14, 3.14, 3.14) with "single-argument vector(3.14) failed"
+	loop 60 times:
+		set {_n} to a random number between -100 and 100
+		set {_vector} to vector({_n})
+		assert {_vector} is vector({_n}, {_n}, {_n}) with "randomly-created single-argument vector equality failed (expected %vector({_n}, {_n}, {_n})%, got %{_vector}%)"
+		assert the x component of {_vector} is {_n} with "single-argument vector x component failed"
+		assert the y component of {_vector} is {_n} with "single-argument vector y component failed"
+		assert the z component of {_vector} is {_n} with "single-argument vector z component failed"