Xray-core: Add Lua script for dns and routing

https://github.com/XTLS/Xray-core/pull/6823

docs/en/development/lua/environment.md

@@ -0,0 +1,35 @@
+# Runtime Environment and Script Loading
+
+## Lua Environment
+
+Xray currently uses GopherLua, which supports Lua 5.1 syntax, Lua 5.2's `goto` statement, and its own [`channel`](https://github.com/yuin/gopher-lua#lua-api).
+
+Xray loads Lua scripts according to the configuration file. The configuration location determines the script's purpose and the available Hooks. See the [Hook reference](./index.md#hook) for each entry point's Hooks and calling conventions.
+
+## Module Loading
+
+API modules are organized by functionality and loaded with `require`:
+
+```lua
+local geodata = require("xray.geodata")
+local log = require("xray.log")
+```
+
+See [Module API](./index.md#module-api) for the module list, and each API reference for function usage.
+
+See [Instances and Lifecycle](./guide/lifecycle.md) for when top-level initialization, such as loading Lua modules and creating objects, runs.
+
+## Script File Paths
+
+The `script` field in the configuration file specifies the path to a Lua script. An empty string or an omitted field disables the script; an absolute path locates the file directly.
+
+Relative paths are searched in the following order. If a path does not exist, the search continues; if it exists but is not a regular file, an error is raised immediately:
+
+1. The directory specified by the `XRAY_LOCATION_CONFDIR` environment variable;
+2. The directory specified by the `XRAY_LOCATION_CONFIG` environment variable;
+3. The Xray process's current working directory;
+4. The directory containing the Xray executable.
+
+See [Environment Variables](../../config/env.md) for these directory settings. Relative paths are not automatically resolved against the directory containing the configuration file.
+
+For example, when the script path is `routing.lua`, Xray searches for the file in the order above. A Windows absolute path can be written as `C:/Xray/routing.lua`; if you use backslashes, escape them as required by your configuration format.