Comment by dreamcompiler

What Forth and Lisp have in common is that they're interactive language construction sets. You don't just write domain code the way you do in C. You invent a language that matches the domain and use that to solve the problem. Don't like the syntax? Change it. Don't like the conditional statement? Invent a new one. Don't like the compiler? Improve it.

These kinds of operations are behind the curtain in C but they're accessible to everybody in Forth and Lisp.