[TUHS] Interesting post by Rob Pike in 1985: Shells, features and interaction

[Random832]

https://groups.google.com/d/msg/net.unix/Cya18ywIebk/2SI8HrSciyYJ

Apparently the 8th Edition shell had the ability to export functions via
the environment.

I'm wondering - were there (are there?) any other shells other than bash
that picked up this feature? How was it implemented, considering this
was the cause of the "Shellshock" vulnerability?