Emacs mode to convert between PCRE, Emacs and rx regexp syntax

 This package provides `pcre2el' or `rxt' (RegeXp Translator or RegeXp
 Tools), a utility for working with regular expressions in Emacs,
 based on a recursive-descent parser for regexp syntax. In addition to
 converting (a subset of) PCRE syntax into its Emacs equivalent, it
 can do the following:
 .
  - convert Emacs syntax to PCRE;
  - convert either syntax to `rx', an S-expression based regexp syntax
    untangle complex regexps by;
  - showing the parse tree in `rx' form and highlighting the;
  - corresponding chunks of code show the complete list of strings
    (productions) matching a regexp, provided the list is finite;
  - provide live font-locking of regexp syntax (so far only for Elisp
    buffers).