spacemacs/contrib/pcre2el

RegeXp Translator Mode

This contrib layer sets up pcre2el or rxt (RegeXp Translator or RegeXp Tools) which is a utility for working with regular expressions in Emacs, to parse, convert, and font-lock PCRE, Emacs and rx regexps.

Using pcre2el you can convert an Emacs Regexp to pcre (and back) (oh and output as rx too.)

Generate all matching strings (productions)

Occasionally you come across a regexp which is designed to match a finite set of strings, e.g. a set of keywords, and it would be useful to recover the original set. (In Emacs you can generate such regexps using regexp-opt'). The commands rxt-convert-to-strings' (C-c /′'), rxt-pcre-to-strings' (C-c / p ′') or rxt-elisp-to-strings' (`C-c / e ′') accomplish this by generating all the matching strings ("productions") of a regexp. (The productions are copied to the kill ring as a Lisp list).

An example in Lisp code:

: (regexp-opt '("cat" "caterpillar" "catatonic"))
:    ;; => "\\(?:cat\\(?:atonic\\|erpillar\\)?\\)"
: (rxt-elisp-to-strings "\\(?:cat\\(?:atonic\\|erpillar\\)?\\)")
:     ;; => '("cat" "caterpillar" "catatonic")

##RE-Builder support

The Emacs RE-Builder is a useful visual tool which allows using several different built-in syntaxes via =reb-change-syntax= (=C-c TAB=). It supports Elisp read and literal syntax and =rx=, but it can only convert from the symbolic forms to Elisp, not the other way. This package hacks the RE-Builder to also work with emulated PCRE syntax, and to convert transparently between Elisp, PCRE and rx syntaxes. PCRE mode reads a delimited Perl-like literal of the form =/ ... /=, and it should correctly support using the =x= and =s= flags.

##Use from Lisp

Example of using the conversion functions:

(rxt-pcre-to-elisp "(abc|def)\\w+\\d+")
   ;; => "\\(\\(?:abc\\|def\\)\\)[_[:alnum:]]+[[:digit:]]+"

Keybindings

pcre2el defines keybindings under C-c / so we'll define them under out perspective map <SPC> R