alternative to Emacs' isearch--with an overview

 Swiper is an Ivy-enhanced alternative to isearch. When a regex
 (regular expression) search is initiated it displays an overview of
 search candidates. The search regex can be split into groups with a
 space. Each group is highlighted with a different face.
 .
 It can double as a quick regex-builder; however, only single
 lines will be matched. Swiper uses Ivy to show an overview of all
 matches.