They contain a lot of features that Larry no doubt considered when designing Perl (since he's been around for a while). Ralph Griswold, a old-time language design guru and advisor of mine at the U of Ariz, wrote both of them, so I guess I'm pretty biased.

Snobol had the novel idea of success or failure of each line of code and allowed you to put optional goto's at the end of each line of code (shudder). You could compile code on the fly (ala eval).

Icon allowed you to get into the guts of the pattern matching behavior, allowing you to use generators (kind of like closures) and explicitly controlling backtracking. Actually it's pattern matching was too low level for me and Perl's re matching is much easier to deal with on a day-to-day basis. At a later time, they instrumented the interpreter and you could write hooks that allowed you to graphically see how algorithms executed in it. You could do things similar to the way that ActiveState's Komodo allows you to view an re as it matches text, but much more as well.

Both of these had dynamic data types and automatic garbage collection to make the programmer's life easier.

Ok back to reality - Perl has fixed a lot of the warts that they had though ...

bluto