== String#to_re

  require 'facets/string/to_re'

  "abc".to_re.assert == /abc/
  "a+bc".to_re.assert == /a+bc/
  "a+bc".to_re(false).assert == /a+bc/
  "a+bc".to_re(true).assert == /a\+bc/

escaped characters

    a = "?"
    b = /#{a.to_rx}/
    assert( b =~ "?" )

== String#to_rx

  "abc".to_rx.assert == /abc/
  "a+bc".to_rx.assert == /a\+bc/
  "a+bc".to_rx(false).assert == /a+bc/
  "a+bc".to_rx(true).assert == /a\+bc/

