This package implements a generic interface for toggling switches and setting options and then invoking an Emacs command which does something with these arguments. The prototypical use is for the command to call an external process, passing on the arguments as command line arguments. But this is only one of many possible uses (though the one this library is optimized for). With the Emacs concept of "prefix arguments" in mind this could be described as "infix arguments with feedback in a buffer". Commands that set the prefix argument for the subsequent command do not limit what that next command could be. But entering a command console popup does limit the selection to the commands defined for that popup, and so we use the term "infix" instead of "prefix".