split internal modules

res/modules/internal/rules.lua

@@ -0,0 +1,70 @@
+local rules = {nexid = 1, 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.reset(name)
+    local rule = rules.get_rule(name)
+    rules.set(rule.default)
+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)
+    local rule = rules.get_rule(name)
+    rule.default = value
+
+    local handlerid
+    if handler ~= nil then
+        handlerid = rules.listen(name, handler)
+    end
+    if rules.get(name) == nil then
+        rules.set(name, value)
+    elseif handler then
+        handler(rules.get(name))
+    end
+    return handlerid
+end
+
+function rules.unlisten(name, id)
+    local rule = rules.rules[name]
+    if rule == nil then
+        return
+    end
+    rule.listeners[utf8.encode(id)] = nil
+end
+
+function rules.clear()
+    rules.rules = {}
+    rules.nextid = 1
+end
+
+return rules