Persistent player attributes no longer a "shared mixin"

And with read cache!

functions.lua

@@ -6,7 +6,7 @@ See init.lua for license.
 
 ]]
 
-local PPA = persistent_player_attributes
+local PPA = thirsty.persistent_player_attributes
 
 PPA.register({
     name = 'thirsty_hydro',

hud.lua

@@ -17,7 +17,7 @@ Any hud needs to define the following functions:
 
 ]]
 
-local PPA = persistent_player_attributes
+local PPA = thirsty.persistent_player_attributes
 
 function thirsty.hud_clamp(value)
     if value < 0 then

persistent_player_attributes.lua

@@ -1,151 +1,109 @@
 --[[
 
-Persistent player attributes (mixin)
-====================================
-
-A mixin to provide persistent player attributes. Simply include and do
-this file in your mod, it will take care to update itself.
-
-Copyright (C) 2015 Ben Deutsch <ben@bendeutsch.de>
-
-License
--------
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
-USA
+Persistent player attributes
 
 ]]
 
-local global_exists = minetest.global_exists or function(name) rawget(_G, name) end
-if not global_exists('persistent_player_attributes') then
-    persistent_player_attributes = {
-        -- trigger "newer version available" below
-        version = 0.000,
+-- change this to inject into other module
+local M = thirsty
+
+M.persistent_player_attributes = {}
+local PPA = M.persistent_player_attributes
+
+--[[
+Helper functions that take care of the conversions *and* the
+clamping for us
+]]
+
+local function _count_for_val(value, def)
+    local count = math.floor((value - def.min) / (def.max - def.min) * 65535)
+    if count < 0 then count = 0 end
+    if count > 65535 then count = 65535 end
+    return count
+end
+local function _val_for_count(count, def)
+    local value = count / 65535 * (def.max - def.min) + def.min
+    if value < def.min then value = def.min end
+    if value > def.max then value = def.max end
+    return value
+end
+-- end helper functions
+
+-- the stash of registered attributes
+
+PPA.defs = {--[[
+    name = {
+        name = "mymod_attr1",
+        min = 0,
+        max = 10,
+        default = 5,
+    },
+]]}
+
+PPA.read_cache = {--[[
+    player_name = {
+        attr1 = value1,
+        attr2 = value2,
+    },
+]]}
+
+--[[
+How to register a new attribute, with named parameters:
+    PPA.register({ name = "mymod_attr1", min = 0, ... })
+]]
+
+PPA.register = function(def)
+    PPA.defs[def.name] = {
+        name = def.name,
+        min = def.min or 0.0,
+        max = def.max or 1.0,
+        default = def.default or def.min or 0.0,
     }
 end
 
---[[
+-- The on_joinplayer handler
 
-DO NOT RESET THE GLOBAL VARIABLE!
+PPA.on_joinplayer = function(player)
+    local inv = player:get_inventory()
+    local player_name = player:get_player_name()
+    PPA.read_cache[player_name] = {}
+    for name, def in pairs(PPA.defs) do
+        inv:set_size(name, 1)
+        if inv:is_empty(name) then
+            -- set default value
+            inv:set_stack(name, 1, ItemStack({ name = ":", count = _count_for_val(def.default, def) }))
+            -- cache default value
+            PPA.read_cache[player_name][name] = def.default
+        end
+    end
+end
 
-The following code *and library users* localize the (overly long)
-library global variable. If another mod later includes a newer version
-of this library, and this newer version changes the global variable
-"persistent_player_attributes", then the mods which previously
-included this mixin may *or may not* be using the old version.
-Chaos will certainly ensue.
+minetest.register_on_joinplayer(PPA.on_joinplayer)
 
+
+--[[ get an attribute, procedural style:
+    local attr1 = PPA.get_value(player, "mymod_attr1")
 ]]
 
-local PPA = persistent_player_attributes
-
-if PPA.version < 1.000 then
-
-    -- the version, minor and patch are in thousandths,
-    -- e.g. 1.2.3 becomes 1.002003
-
-    PPA.version = 1.000
-
-    -- the stash of registered attributes
-
-    PPA.defs = {--[[
-        name = {
-            name = "mymod_attr1",
-            min = 0,
-            max = 10,
-            default = 5,
-        },
-    ]]}
-
-    --[[
-    How to register a new attribute, with named parameters:
-       PPA.register({ name = "mymod_attr1", min = 0, ... })
-    ]]
-
-    PPA.register = function(def)
-        PPA.defs[def.name] = {
-            name = name,
-            min = def.min or 0.0,
-            max = def.max or 1.0,
-            default = def.default or def.min or 0.0,
-        }
-    end
-
-    --[[
-    Helper functions that take care of the conversions *and* the
-    clamping for us
-    ]]
-
-    local function _count_for_val(value, def)
-        local count = math.floor((value - def.min) / (def.max - def.min) * 65535)
-        if count < 0 then count = 0 end
-        if count > 65535 then count = 65535 end
-        return count
-    end
-    local function _val_for_count(count, def)
-        local value = count / 65535 * (def.max - def.min) + def.min
-        if value < def.min then value = def.min end
-        if value > def.max then value = def.max end
-        return value
-    end
-
-    --[[
-    We cannot override / take back a register_on_joinplayer,
-    so we'll only create and register this one, which calls the
-    (overridable) actual handler
-    ]]
-    if not PPA.shim_on_joinplayer then
-        PPA.shim_on_joinplayer = function(player)
-            PPA.on_joinplayer(player)
-        end
-        minetest.register_on_joinplayer(PPA.shim_on_joinplayer)
-    end
-
-    -- The actual on_joinplayer handler
-
-    PPA.on_joinplayer = function(player)
-        local inv = player:get_inventory()
-        for name, def in pairs(PPA.defs) do
-            inv:set_size(name, 1)
-            if inv:is_empty(name) then
-                -- set default value
-                inv:set_stack(name, 1, ItemStack({ name = ":", count = _count_for_val(def.default, def) }))
-            end
-        end
-    end
-
-    --[[ get an attribute, procedural style:
-        local attr1 = PPA.get_value(player, "mymod_attr1")
-    ]]
-
-    PPA.get_value = function(player, name)
+PPA.get_value = function(player, name)
+    local player_name = player:get_player_name()
+    if PPA.read_cache[player_name][name] == nil then
         local def = PPA.defs[name]
         local inv = player:get_inventory()
         local count = inv:get_stack(name, 1):get_count()
-        return _val_for_count(count, def)
+        PPA.read_cache[player_name][name] = _val_for_count(count, def)
     end
-
-    --[[ set an attribute, procedural style:
-        PPA.set_value(player, "mymod_attr1", attr1)
-    ]]
-
-    PPA.set_value = function(player, name, value)
-        local def = PPA.defs[name]
-        local inv = player:get_inventory()
-        inv:set_stack(name, 1, ItemStack({ name = ":", count = _count_for_val(value, def) }))
-    end
-
+    return PPA.read_cache[player_name][name]
 end
 
+--[[ set an attribute, procedural style:
+    PPA.set_value(player, "mymod_attr1", attr1)
+]]
+
+PPA.set_value = function(player, name, value)
+    local def = PPA.defs[name]
+    local inv = player:get_inventory()
+    local player_name = player:get_player_name()
+    PPA.read_cache[player_name][name] = value
+    inv:set_stack(name, 1, ItemStack({ name = ":", count = _count_for_val(value, def) }))
+end