Though, to be fair, a 'real' Lisp interpreter often provides more interactive features. The Lisp interpreter sees the code as Lisp data and interprets that. This enables a few things.
You don't need an interpreter for that. SBCL (as does other compilers) always compiles an expression prior to executing it, even when it's code as data passed to EVAL.
> You don't need an interpreter for that. SBCL (as does other compilers) always compiles an expression prior to executing it, even when it's code as data passed to EVAL.
True, but that's not what a Lisp interpreter does and provides.
I was talking about the difference between an interpreter and a (possibly interactive) compiler. The interpreter works over source code as Lisp data. The compiler does not - it does not matter that the compiler compiles individual forms. At runtime the code is machine code. With an interpreter the code is Lisp data.
Think about it: What difference could that make, if the code gets actually executed by a real Lisp interpreter?