engine: add scripting worldcontext

engine/BUILD

@@ -14,6 +14,7 @@ rust_binary(
         "src/main.rs",
 
         "src/input.rs",
+        "src/scripting.rs",
 
         "src/physics/mod.rs",
         "src/physics/color.rs",
@@ -46,6 +47,7 @@ rust_binary(
         "//lib/ecs",
         "//third_party/cargo:cgmath",
         "//third_party/cargo:image",
+        "//third_party/cargo:mlua",
         "//third_party/cargo:winit",
         "//third_party/cargo:log",
         "//third_party/cargo:env_logger",

engine/src/main.rs

@@ -25,6 +25,7 @@ pub mod input;
 mod render;
 mod util;
 mod physics;
+mod scripting;
 
 use ecs::{Component, World, Processor};
 use ecs_macros::Access;
@@ -217,6 +218,9 @@ fn main() {
     let mut renderer = render::Renderer::initialize(&mut world);
     let main = Main::new(&mut world, &mut renderer);
 
+    let context = scripting::WorldContext::new();
+    context.eval("print(\"Hello, Lua!\", 1337)").unwrap();
+
     log::info!("Starting...");
 
     let mut p = Processor::new(&world);

engine/src/scripting.rs

@@ -0,0 +1,31 @@
+pub struct WorldContext {
+    lua: mlua::Lua,
+}
+
+fn debug_str(v: &mlua::Value) -> String {
+    match v {
+        mlua::Value::String(s) => s.to_str().map_or(format!("{:?}", v), |s| s.to_string()),
+        mlua::Value::Integer(i) => format!("{}", i),
+        _ => format!("{:?}", v),
+    }
+}
+
+impl WorldContext {
+    pub fn new() -> Self {
+        let lua = mlua::Lua::new();
+        log::info!("Lua WorldContext created.");
+        lua.globals().set("print", lua.create_function(|_, vals: mlua::Variadic<mlua::Value>| -> mlua::Result<()> {
+            let msg: Vec<String> = vals.iter().map(|val| debug_str(val)).collect();
+            log::info!("[Lua] {}", msg.join("\t"));
+            Ok(())
+        }).unwrap()).unwrap();
+
+        Self {
+            lua,
+        }
+    }
+
+    pub fn eval(&self, val: &str) -> mlua::Result<()> {
+        self.lua.load(val).exec()
+    }
+}