Why exactly is eval evil?

Question

I know that Lisp and Scheme programmers usually say that eval should be avoided unless strictly necessary. I’ve seen the same recommendation for several program

Answer 1

Eval is fine, as long as you know EXACTLY what is going into it. Any user input going into it MUST be checked and validated and everything. If you don't know how to be 100% sure, then don't do it.

Basically, a user can type in any code for the language in question, and it will execute. You can imagine for yourself how much damage he can do.