Added named systems

src/components.lua

@@ -0,0 +1,29 @@
+-- Components
+
+local PATH = (...):gsub('%.[^%.]+$', '')
+
+local Type = require(PATH..".type")
+
+local Components = {}
+
+function Components.register(name, component)
+    if (type(name) ~= "string") then
+        error("bad argument #1 to 'Components.register' (string expected, got "..type(name)..")", 3)
+    end
+
+    if (not Type.isComponent(component)) then
+        error("bad argument #2 to 'Components.register' (component expected, got "..type(component)..")", 3)
+    end
+
+    if (rawget(Components, name)) then
+        error("bad argument #2 to 'Components.register' (Component with name '"..name.."' is already registerd)", 3)
+    end
+
+    Components[name] = component
+end
+
+return setmetatable(Components, {
+    __index = function(_, name)
+        error("Attempt to index component '"..tostring(name).."' that does not exist / was not registered", 2)
+    end
+})