lua: reduce a bit of boilerplate around registering wezterm.submodule

config/src/lua.rs

@@ -48,6 +48,26 @@ pub fn get_or_create_module<'lua>(lua: &'lua Lua, name: &str) -> anyhow::Result<
     }
 }
 
+pub fn get_or_create_sub_module<'lua>(
+    lua: &'lua Lua,
+    name: &str,
+) -> anyhow::Result<mlua::Table<'lua>> {
+    let wezterm_mod = get_or_create_module(lua, "wezterm")?;
+    let sub = wezterm_mod.get(name)?;
+    match sub {
+        Value::Nil => {
+            let sub = lua.create_table()?;
+            wezterm_mod.set(name, sub.clone())?;
+            Ok(sub)
+        }
+        Value::Table(sub) => Ok(sub),
+        wat => anyhow::bail!(
+            "cannot register module wezterm.{name} as it is already set to a value of type {}",
+            wat.type_name()
+        ),
+    }
+}
+
 /// Set up a lua context for executing some code.
 /// The path to the directory containing the configuration is
 /// passed in and is used to pre-set some global values in

lua-api-crates/mux/src/lib.rs

@@ -1,5 +1,5 @@
 use config::keyassignment::SpawnTabDomain;
-use config::lua::get_or_create_module;
+use config::lua::get_or_create_sub_module;
 use config::lua::mlua::{self, Lua, UserData, UserDataMethods, Value as LuaValue};
 use luahelper::impl_lua_conversion_dynamic;
 use mux::domain::SplitSource;
@@ -20,8 +20,7 @@ fn get_mux() -> mlua::Result<Rc<Mux>> {
 }
 
 pub fn register(lua: &Lua) -> anyhow::Result<()> {
-    let wezterm_mod = get_or_create_module(lua, "wezterm")?;
+    let mux_mod = get_or_create_sub_module(lua, "mux")?;
-    let mux_mod = lua.create_table()?;
 
     mux_mod.set(
         "get_active_workspace",
@@ -102,7 +101,6 @@ pub fn register(lua: &Lua) -> anyhow::Result<()> {
         })?,
     )?;
 
-    wezterm_mod.set("mux", mux_mod)?;
     Ok(())
 }
 

lua-api-crates/window-funcs/src/lib.rs

@@ -1,4 +1,4 @@
-use config::lua::get_or_create_module;
+use config::lua::get_or_create_sub_module;
 use config::lua::mlua::{self, Lua};
 use luahelper::impl_lua_conversion_dynamic;
 use std::collections::HashMap;
@@ -69,8 +69,7 @@ impl From<window::screen::Screens> for Screens {
 }
 
 pub fn register(lua: &Lua) -> anyhow::Result<()> {
-    let wezterm_mod = get_or_create_module(lua, "wezterm")?;
+    let window_mod = get_or_create_sub_module(lua, "gui")?;
-    let window_mod = lua.create_table()?;
 
     window_mod.set(
         "screens",
@@ -84,6 +83,5 @@ pub fn register(lua: &Lua) -> anyhow::Result<()> {
         })?,
     )?;
 
-    wezterm_mod.set("gui", window_mod)?;
     Ok(())
 }