Implement pairs and ipairs for ui.content and ui.layers. Document all iterable types in a uniform way.

apps/openmw/mwlua/uibindings.cpp

@@ -166,6 +166,21 @@ namespace MWLua
             else
                 return sol::nullopt;
         };
+        {
+            auto pairs = [](LuaUi::Content& content)
+            {
+                auto next = [](LuaUi::Content& content, size_t i) -> sol::optional<std::tuple<size_t, sol::table>>
+                {
+                    if (i < content.size())
+                        return std::make_tuple(i + 1, content.at(i));
+                    else
+                        return sol::nullopt;
+                };
+                return std::make_tuple(next, content, 0);
+            };
+            uiContent[sol::meta_function::ipairs] = pairs;
+            uiContent[sol::meta_function::pairs] = pairs;
+        }
 
         auto element = context.mLua->sol().new_usertype<LuaUi::Element>("Element");
         element["layout"] = sol::property(
@@ -233,6 +248,21 @@ namespace MWLua
             options.mInteractive = LuaUtil::getValueOrDefault(LuaUtil::getFieldOrNil(opt, "interactive"), true);
             context.mLuaManager->addAction(std::make_unique<LayerAction>(name, afterName, options, context.mLua));
         };
+        {
+            auto pairs = [layers](const sol::object&)
+            {
+                auto next = [](const sol::table& l, size_t i) -> sol::optional<std::tuple<size_t, std::string>>
+                {
+                    if (i < LuaUi::Layers::size())
+                        return std::make_tuple(i + 1, LuaUi::Layers::at(i));
+                    else
+                        return sol::nullopt;
+                };
+                return std::make_tuple(next, layers, 0);
+            };
+            layers[sol::meta_function::pairs] = pairs;
+            layers[sol::meta_function::ipairs] = pairs;
+        }
         api["layers"] = LuaUtil::makeReadOnly(layers);
 
         sol::table typeTable = context.mLua->newTable();

components/lua/luastate.cpp

@@ -59,6 +59,23 @@ namespace LuaUtil
 
         mLua["writeToLog"] = [](std::string_view s) { Log(Debug::Level::Info) << s; };
         mLua["cmetatable"] = [](const sol::table& v) -> sol::object { return v[sol::metatable_key]; };
+
+        // Some fixes for compatibility between different Lua versions
+        if (mLua["unpack"] == sol::nil)
+            mLua["unpack"] = mLua["table"]["unpack"];
+        else if (mLua["table"]["unpack"] == sol::nil)
+            mLua["table"]["unpack"] = mLua["unpack"];
+        if (LUA_VERSION_NUM <= 501)
+        {
+            mLua.script(R"(
+                local _pairs = pairs
+                local _ipairs = ipairs
+                local _cmeta = cmetatable
+                pairs = function(v) return ((_cmeta(v) or v).__pairs or _pairs)(v) end
+                ipairs = function(v) return ((_cmeta(v) or v).__ipairs or _ipairs)(v) end
+            )");
+        }
+
         mLua.script(R"(
             local _pairs = pairs
             local _ipairs = ipairs
@@ -78,22 +95,6 @@ namespace LuaUtil
             function ipairsForReadOnly(v) return _ipairs(_cmeta(v).__index) end
         )");
 
-        // Some fixes for compatibility between different Lua versions
-        if (mLua["unpack"] == sol::nil)
-            mLua["unpack"] = mLua["table"]["unpack"];
-        else if (mLua["table"]["unpack"] == sol::nil)
-            mLua["table"]["unpack"] = mLua["unpack"];
-        if (LUA_VERSION_NUM <= 501)
-        {
-            mLua.script(R"(
-                local _pairs = pairs
-                local _ipairs = ipairs
-                local _cmeta = cmetatable
-                pairs = function(v) return ((_cmeta(v) or v).__pairs or _pairs)(v) end
-                ipairs = function(v) return ((_cmeta(v) or v).__ipairs or _ipairs)(v) end
-            )");
-        }
-
         mSandboxEnv = sol::table(mLua, sol::create);
         mSandboxEnv["_VERSION"] = mLua["_VERSION"];
         for (const std::string& s : safeFunctions)

docs/source/generate_luadoc.sh

@@ -67,4 +67,3 @@ cd $FILES_DIR/builtin_scripts
 $DOCUMENTOR_PATH -f doc -d $OUTPUT_DIR openmw_aux/*lua
 $DOCUMENTOR_PATH -f doc -d $OUTPUT_DIR scripts/omw/ai.lua
 $DOCUMENTOR_PATH -f doc -d $OUTPUT_DIR scripts/omw/camera.lua
-

docs/source/reference/lua-scripting/api.rst

@@ -25,6 +25,7 @@ Lua API reference
     openmw_aux_time
     interface_ai
     interface_camera
+    iterables
 
 
 - :ref:`Engine handlers reference`

docs/source/reference/lua-scripting/iterables.rst

@@ -0,0 +1,50 @@
+Iterable types
+==============
+
+List Iterable
+-------------
+
+An iterable with defined size and order.
+
+.. code-block:: Lua
+
+   -- can iterate over the list with pairs
+   for i, v in pairs(list) do
+   -- ...
+   end
+
+.. code-block:: Lua
+
+   -- can iterate over the list with ipairs
+   for i, v in ipairs(list) do
+   -- ...
+   end
+
+.. code-block:: Lua
+
+   -- can get total size with the size # operator
+   local length = #list
+
+.. code-block:: Lua
+
+   -- can index the list with numbers
+   for i = 1, length do
+   list[i]
+   end
+
+Map Iterable
+------------
+
+An iterable with undefined order.
+
+.. code-block:: Lua
+
+   -- can iterate over the map with pairs
+   for k, v in pairs(map) do
+   -- ...
+   end
+
+.. code-block:: Lua
+
+   -- can index the map by key
+   map[key]

docs/source/reference/lua-scripting/overview.rst

@@ -498,7 +498,7 @@ At some moment it will send the 'DamagedByDarkPower' event to all nearby actors:
     local nearby = require('openmw.nearby')
 
     local function onActivated()
-        for i, actor in nearby.actors:ipairs() do
+        for i, actor in ipairs(nearby.actors) do
             local dist = (self.position - actor.position):length()
             if dist < 500 then
                 local damage = (1 - dist / 500) * 200

files/lua_api/openmw/core.lua

@@ -289,9 +289,9 @@
 
 
 -------------------------------------------------------------------------------
--- List of GameObjects.
+-- List of GameObjects. Implements [iterables#List](iterables.html#List) of #GameObject
 -- @type ObjectList
--- @extends #list<#GameObject>
+-- @list <#GameObject>
 
 -------------------------------------------------------------------------------
 -- Filter list with a Query.

files/lua_api/openmw/ui.lua

@@ -64,12 +64,16 @@
 -- @field #Content content Optional @{openmw.ui#Content} of children layouts
 
 ---
--- Layers
+-- Layers. Implements [iterables#List](iterables.html#List) of #string.
 -- @type Layers
+-- @list <#string>
 -- @usage
 -- ui.layers.insertAfter('HUD', 'NewLayer', { interactive = true })
 -- local fourthLayerName = ui.layers[4]
 -- local windowsIndex = ui.layers.indexOf('Windows')
+-- for i, name in ipairs(ui.layers) do
+--   print('layer', i, name)
+-- end
 
 ---
 -- Index of the layer with the givent name. Returns nil if the layer doesn't exist
@@ -85,7 +89,8 @@
 -- @param #table options Table with a boolean `interactive` field (default is true). Layers with interactive = false will ignore all mouse interactions.
 
 ---
--- Content. An array-like container, which allows to reference elements by their name
+-- Content. An array-like container, which allows to reference elements by their name.
+-- Implements [iterables#List](iterables.html#List) of #Layout and [iterables#Map](iterables.html#Map) of #string to #Layout.
 -- @type Content
 -- @list <#Layout>
 -- @usage