Initial menu system by claude

luprex/lua/menu.lua

@@ -0,0 +1,68 @@
+----------------------------------------------------------------
+--
+-- To add a menu to an object (such as a Brick Oven), you will
+-- be adding a function 'lookmenu' to the appropriate class,
+-- like this:
+--
+-- function brickoven.lookmenu(add)
+--    add("Light Oven", function () ... end)
+--    add("Add Fuel", function () ... end)
+-- end
+--
+-- This function will get called twice: once in a 'probe' when
+-- Unreal wants to know what menu items exist, and a second time
+-- in an 'invoke' to find the right closure.  The 'add' function
+-- which is passed in can therefore be one of two functions.
+--
+-- In probe mode, the goal is to build up an array that looks
+-- like this:
+--
+--   {"Light Oven", "Add Fuel"}
+--
+-- So therefore, in probe mode, the 'add' function is a closure
+-- that adds the label to the array.
+--
+-- In invoke mode, the goal is to find the right closure.  So
+-- therefore, in invoke mode, the 'add' function is a closure
+-- that compares the label to the menu item which was already
+-- selected.  If there's a match, it records the closure.
+--
+----------------------------------------------------------------
+
+makeclass('engio')
+
+function engio.getmenu()
+    local class = tangible.getclass(place)
+
+    -- if the tangible doesn't have a 'lookmenu' function, do nothing
+    if class == nil or class.lookmenu == nil then
+        return {}
+    end
+
+    local items = {}
+    local add = function(label, closure)
+        table.insert(items, label)
+    end
+    class.lookmenu(add)
+    return items
+end
+
+function engio.pressmenu(label)
+    local class = tangible.getclass(place)
+
+    -- if the tangible doesn't have a 'lookmenu' function, do nothing
+    if class == nil or class.lookmenu == nil then
+        return
+    end
+
+    local result = nil
+    local add = function(lbl, closure)
+        if (lbl == label) then
+            result = closure
+        end
+    end
+    class.lookmenu(add)
+    if result ~= nil then
+        result()
+    end
+end