Initial data commit

Task/Compound-data-type/Lua/compound-data-type-1.lua

@@ -0,0 +1,8 @@
+a = {x = 1; y = 2}
+b = {x = 3; y = 4}
+c = {
+    x = a.x + b.x;
+    y = a.y + b.y
+}
+print(a.x, a.y)  --> 1 2
+print(c.x, c.y)  --> 4 6

Task/Compound-data-type/Lua/compound-data-type-2.lua

@@ -0,0 +1,9 @@
+cPoint = {}                                           -- metatable (behaviour table)
+function newPoint(x, y)                               -- constructor
+    local pointPrototype = {}                         -- prototype declaration
+    function pointPrototype:getX() return x end       -- public method
+    function pointPrototype:getY() return y end       -- public method
+    function pointPrototype:getXY() return x, y end   -- public method
+    function pointPrototype:type() return "point" end -- public method
+    return setmetatable(pointPrototype, cPoint)       -- set behaviour and return the pointPrototype
+end--newPoint

Task/Compound-data-type/Lua/compound-data-type-3.lua

@@ -0,0 +1,9 @@
+local oldtype = type;                   -- store original type function
+function type(v)
+    local vType = oldtype(v)
+    if (vType=="table" and v.type) then
+        return v:type()                 -- bypass original type function if possible
+    else
+        return vType
+    end--if vType=="table"
+end--type

Task/Compound-data-type/Lua/compound-data-type-4.lua

@@ -0,0 +1,14 @@
+function cPoint.__add(op1, op2)  -- add the x and y components
+    if type(op1)=="point" and type(op2)=="point" then
+        return newPoint(
+            op1:getX()+op2:getX(),
+            op1:getY()+op2:getY())
+    end--if type(op1)
+end--cPoint.__add
+function cPoint.__sub(op1, op2)  -- subtract the x and y components
+    if (type(op1)=="point" and type(op2)=="point") then
+        return newPoint(
+            op1:getX()-op2:getX(),
+            op1:getY()-op2:getY())
+    end--if type(op1)
+end--cPoint.__sub

Task/Compound-data-type/Lua/compound-data-type-5.lua

@@ -0,0 +1,7 @@
+a = newPoint(1, 2)
+b = newPoint(3, 4)
+c = a + b             -- using __add behaviour
+print(a:getXY())      --> 1 2
+print(type(a))        --> point
+print(c:getXY())      --> 4 6
+print((a-b):getXY())  --> -2 -2  -- using __sub behaviour