This package for Emacs was inspired by auto-pair-plus which seems to be abandoned and not working with latest autopair. But I love the functionality of escaping inner quotes when quoting region so here is a try to implement it as a separate package.
Emacs packages cl, fontlock, autopair
Add (require 'autopair-escape-region) to your initialization file.
When autopair-escape-region-when-quoting (enabled by default) is
true, then it will appropriately quote the string. For example
selecting the following string:
This is a test of the quoting system, "this is only a test"
And pressing quote, gives:
"This is a test of the quoting system, \"this is only a test\""
Quoting the whole phrase again gives:
"\"This is a test of the quoting system, \\\"this is only a test\\\"\""