Access Ruby variables in the Homestead.yaml file by means of string formatting in homestead.rb (Laravel Vagrant template)

homestead_env_var_replacement.rb

# ...
        # Register All Of The Configured Shared Folders
        if settings.include? 'folders'
            settings["folders"].each do |folder|

                # folder["map"].sub!('{{USERPROFILE}}', ENV['USERPROFILE'])
                folder["map"] = folder["map"] % { :USERPROFILE => ENV['USERPROFILE'] }

                if File.exists? File.expand_path(folder["map"])
                  # ...
                end
            end
        end
# ...
# Yaml sample:
# folders:
#     - map: "%{USERPROFILE}/tmp"
#       to: /home/vagrant/apps
#       options:
#           fsnotify: true
# ...