refactor(lua): make vim submodule lazy loading declarative

This will allow us to also use the same logic for lua threads and
processes, later.

4 files changed, 40 insertions, 41 deletions

diff --git a/runtime/lua/vim/_editor.lua b/runtime/lua/vim/_editor.lua
index ddd1147468..2251aca004 100644
--- a/runtime/lua/vim/_editor.lua
+++ b/runtime/lua/vim/_editor.lua
@@ -3,9 +3,11 @@
 -- Lua code lives in one of three places:
 --    1. runtime/lua/vim/ (the runtime): For "nice to have" features, e.g. the
 --       `inspect` and `lpeg` modules.
---    2. runtime/lua/vim/shared.lua: Code shared between Nvim and tests.
---       (This will go away if we migrate to nvim as the test-runner.)
---    3. runtime/lua/vim/_editor.lua: Compiled-into Nvim itself.
+--    2. runtime/lua/vim/shared.lua: pure lua functions which always
+--       are available. Used in the test runner, as well as worker threads
+--       and processes launched from Nvim.
+--    3. runtime/lua/vim/_editor.lua: Code which directly interacts with
+--       the Nvim editor state. Only available in the main thread.
 --
 -- Guideline: "If in doubt, put it in the runtime".
 --
@@ -35,43 +37,19 @@
 --    - https://github.com/howl-editor/howl/tree/master/lib/howl/util
 
 local vim = assert(vim)
-assert(vim.inspect)
 
 -- These are for loading runtime modules lazily since they aren't available in
 -- the nvim binary as specified in executor.c
-setmetatable(vim, {
-  __index = function(t, key)
-    if key == 'treesitter' then
-      t.treesitter = require('vim.treesitter')
-      return t.treesitter
-    elseif key == 'filetype' then
-      t.filetype = require('vim.filetype')
-      return t.filetype
-    elseif key == 'F' then
-      t.F = require('vim.F')
-      return t.F
-    elseif require('vim.uri')[key] ~= nil then
-      -- Expose all `vim.uri` functions on the `vim` module.
-      t[key] = require('vim.uri')[key]
-      return t[key]
-    elseif key == 'lsp' then
-      t.lsp = require('vim.lsp')
-      return t.lsp
-    elseif key == 'highlight' then
-      t.highlight = require('vim.highlight')
-      return t.highlight
-    elseif key == 'diagnostic' then
-      t.diagnostic = require('vim.diagnostic')
-      return t.diagnostic
-    elseif key == 'keymap' then
-      t.keymap = require('vim.keymap')
-      return t.keymap
-    elseif key == 'ui' then
-      t.ui = require('vim.ui')
-      return t.ui
-    end
-  end
-})
+for k,v in pairs {
+  treesitter=true;
+  filetype = true;
+  F=true;
+  lsp=true;
+  highlight=true;
+  diagnostic=true;
+  keymap=true;
+  ui=true;
+} do vim._submodules[k] = v end
 
 vim.log = {
   levels = {
diff --git a/runtime/lua/vim/_init_packages.lua b/runtime/lua/vim/_init_packages.lua
index dcb402287c..7d27741f1b 100644
--- a/runtime/lua/vim/_init_packages.lua
+++ b/runtime/lua/vim/_init_packages.lua
@@ -50,7 +50,25 @@ table.insert(package.loaders, 2, vim._load_package)
 
 -- builtin functions which always should be available
 require'vim.shared'
-vim.inspect = require'vim.inspect'
+
+vim._submodules = {inspect=true}
+
+-- These are for loading runtime modules in the vim namespace lazily.
+setmetatable(vim, {
+  __index = function(t, key)
+    if vim._submodules[key] then
+      t[key] = require('vim.'..key)
+      return t[key]
+    elseif vim.startswith(key, 'uri_') then
+      local val = require('vim.uri')[key]
+      if val ~= nil then
+        -- Expose all `vim.uri` functions on the `vim` module.
+        t[key] = val
+        return t[key]
+      end
+    end
+  end
+})
 
 --- <Docs described in |vim.empty_dict()| >
 ---@private
diff --git a/runtime/lua/vim/shared.lua b/runtime/lua/vim/shared.lua
index 48d0bd3672..8124b23eb1 100644
--- a/runtime/lua/vim/shared.lua
+++ b/runtime/lua/vim/shared.lua
@@ -1,8 +1,10 @@
 -- Functions shared by Nvim and its test-suite.
 --
--- The singular purpose of this module is to share code with the Nvim
--- test-suite. If, in the future, Nvim itself is used to run the test-suite
--- instead of "vanilla Lua", these functions could move to runtime/lua/vim/_editor.lua
+-- These are "pure" lua functions not depending of the state of the editor.
+-- Thus they should always be available whenever nvim-related lua code is run,
+-- regardless if it is code in the editor itself, or in worker threads/processes,
+-- or the test suite. (Eventually the test suite will be run in a worker process,
+-- so this wouldn't be a separate case to consider)
 
 local vim = vim or {}
 
diff --git a/src/nvim/CMakeLists.txt b/src/nvim/CMakeLists.txt
index 9abefbe02a..9f29cae29d 100644
--- a/src/nvim/CMakeLists.txt
+++ b/src/nvim/CMakeLists.txt
@@ -342,6 +342,7 @@ add_custom_command(
       ${LUA_KEYMAP_MODULE_SOURCE} "vim.keymap"
   DEPENDS
     ${CHAR_BLOB_GENERATOR}
+    ${LUA_INIT_PACKAGES_MODULE_SOURCE}
     ${LUA_EDITOR_MODULE_SOURCE}
     ${LUA_SHARED_MODULE_SOURCE}
     ${LUA_INSPECT_MODULE_SOURCE}