Split vector.new into 3 constructors

builtin/common/tests/vector_spec.lua

@@ -31,6 +31,21 @@ describe("vector", function()
 		end)
 	end)
 
+	it("zero()", function()
+		assert.same({x = 0, y = 0, z = 0}, vector.zero())
+		assert.same(vector.new(), vector.zero())
+		assert.equal(vector.new(), vector.zero())
+		assert.is_true(vector.check(vector.zero()))
+	end)
+
+	it("copy()", function()
+		local v = vector.new(1, 2, 3)
+		assert.same(v, vector.copy(v))
+		assert.same(vector.new(v), vector.copy(v))
+		assert.equal(vector.new(v), vector.copy(v))
+		assert.is_true(vector.check(vector.copy(v)))
+	end)
+
 	it("indexes", function()
 		local some_vector = vector.new(24, 42, 13)
 		assert.equal(24, some_vector[1])

builtin/common/vector.lua

@@ -30,16 +30,28 @@ local function fast_new(x, y, z)
 end
 
 function vector.new(a, b, c)
-	if type(a) == "table" then
+	if a and b and c then
-		assert(a.x and a.y and a.z, "Invalid vector passed to vector.new()")
-		return fast_new(a.x, a.y, a.z)
-	elseif a then
-		assert(b and c, "Invalid arguments for vector.new()")
 		return fast_new(a, b, c)
 	end
+
+	-- deprecated, use vector.copy and vector.zero directly
+	if type(a) == "table" then
+		return vector.copy(a)
+	else
+		assert(not a, "Invalid arguments for vector.new()")
+		return vector.zero()
+	end
+end
+
+function vector.zero()
 	return fast_new(0, 0, 0)
 end
 
+function vector.copy(v)
+	assert(v.x and v.y and v.z, "Invalid vector passed to vector.copy()")
+	return fast_new(v.x, v.y, v.z)
+end
+
 function vector.from_string(s, init)
 	local x, y, z, np = string.match(s, "^%s*%(%s*([^%s,]+)%s*[,%s]%s*([^%s,]+)%s*[,%s]" ..
 			"%s*([^%s,]+)%s*[,%s]?%s*%)()", init)

doc/lua_api.txt

@@ -3271,10 +3271,13 @@ For the following functions, `v`, `v1`, `v2` are vectors,
 vectors are written like this: `(x, y, z)`:
 
 * `vector.new([a[, b, c]])`:
-    * Returns a vector.
+    * Returns a new vector `(a, b, c)`.
-    * A copy of `a` if `a` is a vector.
+    * Deprecated: `vector.new()` does the same as `vector.zero()` and
-    * `(a, b, c)`, if all of `a`, `b`, `c` are defined numbers.
+      `vector.new(v)` does the same as `vector.copy(v)`
-    * `(0, 0, 0)`, if no arguments are given.
+* `vector.zero()`:
+    * Returns a new vector `(0, 0, 0)`.
+* `vector.copy(v)`:
+    * Returns a copy of the vector `v`.
 * `vector.from_string(s[, init])`:
     * Returns `v, np`, where `v` is a vector read from the given string `s` and
       `np` is the next position in the string after the vector.