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------------------------------------------------------------------ -- menu.lua ------------------------------------------------------------------ do local curriedMethod, method, meta = {}, {}, {} -- __index either executes a method from method or curries a method from -- curriedMethod with its self argument. This allows all calls to be with -- "." rather than ":" and also allows you to write obj.foo instead of -- obj.foo() for methods which don't require arguments. It might -- not be great design, but it is interesting. :) function meta:__index(key) local func = method[key] if func then return func(self) else func = curriedMethod[key] if func then local rv = function(a, b) return func(self, a, b) end self[key] = rv return rv end end end -- quick and dirty display routine. local DASHES = string.rep('-', 80) local DOUBLES = string.rep('=', 80) local function drawmenu(self) local maxsize = string.len(self.name) + 2 local item = 0 for i = 1, self.n do local sz = 6 + string.len(self[1][i]) if maxsize < sz then maxsize = sz end end if maxsize > 75 then maxsize = 75 end local sepformat = " +%-"..maxsize.."."..maxsize.."s+\n" local nameformat = " | %-"..(maxsize - 2).."."..(maxsize-2).."s |\n" local itemformat = " | %2i. %-"..(maxsize - 6).."."..(maxsize-6).."s |\n" local sepline = string.format(sepformat, DASHES) io.write("\n", string.format(sepformat, DOUBLES)) io.write(string.format(nameformat, self.name)) io.write(string.format(sepformat, DOUBLES)) for i = 1, self.n do if self[2][i] then item = item + 1 io.write(string.format(itemformat, item, self[1][i])) else io.write(sepline) end end io.write(sepline) end -- Equally quick and dirty menu execution. Tail calls the function -- associated with the selected menu item. local function domenu(self) drawmenu(self) io.write("\n\nSelect a menu item: ") while true do local choice = io.read("*l") if choice == nil then return false end local _, _, item = string.find(choice, "^%s*(%d+)%s*$") if item then item = item + 0 -- force numeric conversion for i = 1, self.n do if self[2][i] then if item == 1 then return self[2][i]() end item = item - 1 end end end io.write("\nSelection not valid. Try again: ") end end -- Create a new menu with given name and back reference. local function newmenu(name, back) return setmetatable({ {}, {}, -- [1] is the menu label, [2] is the associated function name = name, back = back, n = 0 }, meta) end -- insert a label and a function at the end of a menu local function put(self, name, action) local n = self.n + 1 self.n = n self[1][n] = name self[2][n] = action return self end -- Now the actual menu methods. -- add(label, id) function curriedMethod:add(name, id) return put(self, name, function() return id end) end -- I personally would use functions instead of ids curriedMethod.addf = put -- create and open a submenu with the given name function curriedMethod:sub(name) local submenu = newmenu(self.name .. " / " .. name, self) put(self, name.." -->", function() return domenu(submenu) end) return submenu end -- create a new, unrelated menu. You cannot use super afterwards function curriedMethod:new(name) return newmenu(name) end -- go back to the previous level, after introducing the automatic Back label -- unless this is a top-level menu function method:super() local mom = self.back if mom then put(self, "-") put(self, "<-- Back", function() return domenu(self.back) end) return self.back else return self end end -- insert a separator line function method:sep() return put(self, "-") end -- and a function to actually execute the thing curriedMethod.run = domenu -- Finally, we define the Menu "object" -- This is a bit of a kludge, because all menus respond to "new" -- in the same way. So you could actually just use Menu as your -- top-level menu. Menu = newmenu("") end -- OK, let's give it a whirl local function about_dialog() io.write [[ Menu system written by RiciLake in order to demonstrate some interesting syntactic possibilities in Lua This program is released into the public domain. But if you find it useful, you could certainly buy me a coffee sometime ]] return "About menu" end local ID_CAMPAIGN, ID_RANDOMMAP, ID_LOADGAME, ID_EXIT = "ID_CAMPAIGN", "ID_RANDOMMAP", "ID_LOADGAME", false mainMenu = Menu.new "Main" .sub "New" .add("New Campaign", ID_CAMPAIGN) .add("New Random Map", ID_RANDOMMAP) .super .add("Load Game", ID_LOADGAME) .sep .addf("About", about_dialog) .sep .add("Exit", ID_EXIT) while true do local selection = mainMenu.run() if not selection then break end print("Selected: ", selection) end
--RiciLake