args: add method to retrieve formula and casks

Library/Homebrew/cli/args.rb

@@ -38,6 +38,7 @@ module Homebrew
         @resolved_formulae = nil
         @formulae_paths = nil
         @casks = nil
+        @formulae_and_casks = nil
         @kegs = nil
 
         self[:named_args] = named_args
@@ -107,6 +108,23 @@ module Homebrew
                                          .freeze
       end
 
+      def formulae_and_casks
+        require "cask/cask_loader"
+        require "cask/exceptions"
+
+        @formulae_and_casks ||= downcased_unique_named.map do |name|
+          begin
+            Formulary.factory(name, spec)
+          rescue FormulaUnavailableError => e
+            begin
+              Cask::CaskLoader.load(name)
+            rescue Cask::CaskUnavailableError
+              raise e
+            end
+          end
+        end.uniq.freeze
+      end
+
       def kegs
         require "keg"
         require "formula"