Compose a regular expression from other RegExp objects

You can create a Regexp Show archive.org snapshot object from existing Regexp objects by using the interpolation syntax you know from strings:

re1 = /x/
re2 = /a#{re1}b/
'aaxbb' =~ re2 # => 1

Note

If your regular expression contains backreferences like \1, they may no longer refer to the correct capture group after concatentation.