neovim: add formatting module

neovim/.config/nvim/lua/formatting.lua

@@ -0,0 +1,70 @@
+--[[
+-- this file breaks my brain with all of these booleans, but it seems to work
+--]]
+
+local M = {
+  -- false    = formatting enabled for all buffers
+  -- true     = formatting disabled for all buffers
+  -- number[] = formatting disabled for only these buffers
+  ---@type true | false | number[]
+  _disabled_buffers = false,
+}
+
+---@param buf number
+---@return boolean, boolean
+--- returns 2 booleans: enabled for all buffers, enabled for this buffer
+function M._is_enabled(buf)
+  if M._disabled_buffers == true then
+    return false, false
+  end
+
+  if type(M._disabled_buffers) == "table" then
+    local enabled = not vim.tbl_contains(M._disabled_buffers, buf)
+    return true, enabled
+  end
+
+  return true, true
+end
+
+---@param buf number
+function M.is_enabled(buf)
+  local _, enabled = M._is_enabled(buf)
+  return enabled
+end
+
+function M.register_user_commands()
+  vim.api.nvim_create_user_command("FormattingEnable", function()
+    M._disabled_buffers = false
+  end, {})
+
+  vim.api.nvim_create_user_command("FormattingEnableBuf", function()
+    local current_buf = vim.api.nvim_get_current_buf()
+
+    if type(M._disabled_buffers) == "table" then
+      local new_table = {}
+      for _, b in ipairs(M._disabled_buffers) do
+        if b ~= current_buf then
+          table.insert(new_table, b)
+        end
+      end
+      M._disabled_buffers = new_table
+    else
+      M._disabled_buffers = false
+    end
+  end, {})
+
+  vim.api.nvim_create_user_command("FormattingDisable", function()
+    M._disabled_buffers = true
+  end, {})
+
+  vim.api.nvim_create_user_command("FormattingDisableBuf", function()
+    local current_buf = vim.api.nvim_get_current_buf()
+    if type(M._disabled_buffers) == "table" then
+      table.insert(M._disabled_buffers, current_buf)
+    else
+      M._disabled_buffers = { current_buf }
+    end
+  end, {})
+end
+
+return M