Maybe I'm missing something, but I don't see any infix notation on the linked page.
(car nil) => NIL
Shouldn't they say, for example:
(eq (car x) (first x))
Sure, it's the same, both imply a test for equality or in this case an assertion of equality. However, '==' is not part of this language and there is reason to use it other than the alternative is less obvious and clear.
Using infix metanotation to describe Lisp semantics is a convention that goes back to McCarthy.
The C++ standard uses tables for the equivalent purpose, not C++ declarations, like at §23.2.1 in C++11. Does this mean that C++ should move from header files to an RDBMS?
This is true in both infix notation and in prefix notation.