samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/overloadproduct.t

@@ -0,0 +1,65 @@
+
+local ans = {
+{1,1,1,1};
+{2,2,2,2};
+{1,2,1,2};
+{3,3,3,3};
+{1,1,3,3};
+{0,2,3,0};
+{1,2,3,0};
+{4,4,4,4};
+{1,0,0,4};
+{2,2,4,4};
+{1,2,0,4};
+{3,4,3,4};
+{1,0,3,4};
+{0,2,3,4};
+{1,2,3,4};
+}
+function create(foo,a,b,c,d)
+	if a then
+		terra foo(a : int, b : int)
+			return 1
+		end
+	end
+	if b then
+		terra foo(a : int, b : double)
+			return 2
+		end
+	end
+	if c then
+		terra foo(a : double, b : int)
+			return 3
+		end
+	end
+	if d then
+		terra foo(a : double, b : double)
+			return 4
+		end
+	end
+end
+
+local function bitset(i,b)
+	return bit.band(bit.rshift(i,b),1) == 1
+end
+
+for i = 1,15 do
+	local terra foo
+	local a,b,c,d = bitset(i,0),bitset(i,1),bitset(i,2),bitset(i,3)
+	create(foo, a,b,c,d)
+	local function trycall(arg1,arg2)
+		local r = 0
+		pcall(function()
+			local terra testit()
+				var a : arg1, b : arg2 = 0,0
+				return foo(a,b)
+			end
+			r = testit()
+		end)
+		return r
+	end
+	local r = {trycall(int,int),trycall(int,double),trycall(double,int),trycall(double,double)}
+	for j,rr in ipairs(r) do
+		assert(rr == ans[i][j])
+	end
+end