[tromp]

> Lisp gives you a programming language in which you don't have to write a cryptic 42 page one-liner to have an implementation of lambda calculus.

You totally misunderstood what the 42 pages are. They are not an implementation of LC, but an implementation of LISP in LC.

> Lisp gives you a way to talk about lambda calculus, in a way that executes.

LC gives you that too; it allows you to encode lambda terms as bitstrings, which can be represented as lambda terms themselves.

> But lambda calculus doesn't explain what x is

In the binary encoding, x is a de-Bruijn index: a natural number indicating the nesting level of the binding lambda.

> Lisp closes the circle

So does Binary Lambda Calculus.

[kazinator]

> You totally misunderstood what the 42 pages are.

There is a deliberate reversal of roles in my sentence that may not be obvious at a glance.