add rules & add 'show-content-access' rule

res/scripts/stdcmd.lua

@@ -223,3 +223,35 @@ console.add_command(
         fragment:place({x, y, z}, rotation)
     end
 )
+
+console.add_command(
+    "rule.set name:str value:bool",
+    "Set rule value",
+    function(args, kwargs)
+        local name = args[1]
+        local value = args[2]
+        rules.set(name, value)
+        return "rule '"..name.."' set to "..tostring(value)
+    end
+)
+
+console.add_command(
+    "rule.list",
+    "Show registered rules list",
+    function(args, kwargs)
+        local names = ""
+        for name, rule in pairs(rules.rules) do
+            if #names > 0 then
+                names = names .. "\n  "
+            else
+                names = "  "
+            end
+            local value = rule.value
+            if value == nil then
+                value = "not set"
+            end
+            names = names .. name .. ":\t" .. tostring(value)
+        end
+        return "registered rules:\n" .. names
+    end
+)

res/scripts/stdlib.lua

@@ -168,6 +168,64 @@ end
 
 math.randomseed(time.uptime() * 1536227939)
 
+rules = {nexid = 1, rules = {}}
+local _rules = rules
+
+function _rules.get_rule(name)
+    local rule = _rules.rules[name]
+    if rule == nil then
+        rule = {listeners={}}
+        _rules.rules[name] = rule
+    end
+    return rule
+end
+
+function _rules.get(name)
+    local rule = _rules.rules[name]
+    if rule == nil then
+        return nil
+    end
+    return rule.value
+end
+
+function _rules.set(name, value)
+    local rule = _rules.get_rule(name)
+    rule.value = value
+    for _, handler in pairs(rule.listeners) do
+        handler(value)
+    end
+end
+
+function _rules.listen(name, handler)
+    local rule = _rules.get_rule(name)
+    local id = _rules.nexid
+    _rules.nextid = _rules.nexid + 1
+    rule.listeners[utf8.encode(id)] = handler
+    return id
+end
+
+function _rules.create(name, value, handler)
+    print(name, value, handler)
+    _rules.set(name, value)
+    return _rules.listen(name, handler)
+end
+
+function _rules.unlisten(name, id)
+    local rule = _rules.get_rule(name)
+    rule.listeners[utf8.encode(id)] = nil
+end
+
+function _rules.clear()
+    _rules.rules = {}
+    _rules.nextid = 1
+end
+
+function __vc_create_hud_rules()
+    _rules.create("show-content-access", hud._is_content_access(), function(value)
+        hud._set_content_access(value)
+    end)
+end
+
 -- --------- Deprecated functions ------ --
 local function wrap_deprecated(func, name, alternatives)
     return function (...)