In the specification section of SRFI 204, it says "identifiers will
match anything, and make the corresponding binding available in the
body", which I read as that the identifiers are lexically bound in an
extended environment, in which the body is evaluated.

The sample implementation, however, fails to respect the correct
lexical scoping in some cases:

(match '1 ((and odd (? odd)) odd))

The expected value of this expression (and according to how match is
specified in SRFI 204) is 1. The sample implementation, however, fails
with an error because the binding of odd is introduced too early,
namely in a scope surrounding the pattern `(? odd)` as well.

To make the sample implementation do the correct thing, it has to
defer all actual bindings or bind to temporary variables first.

Marc