[Chicken-users] eval and local variables

[Chicken Monk]

Hi,

I noticed that the following doesn't work in Chicken:

(define a 42)

(define (foo b)
    (let ((c (+ b 1)))
        (let ((env (interaction-environment)))
            (eval '(+ a b c) env))))
            ; doesn't work with or without the env.

(print (foo 3))

Error: unbound variable: b

I would expect eval to "know" about b and c as well.  The manual, 
however, points out that it uses (interactive-environment) by default.

A few questions:

1. Why is (interactive-environment) the default?  (Or, why doesn't eval 
have access to all the variables that "regular" code would have?)

2. Is it possible to get the "local environment" (which should have 
access to b and c)?  Is there even such a thing, or am I seeing this 
completely wrong?

3. Are there other ways to make this work?  I am aware of the 
environments egg, but having to manually add values to an environment 
does not sound very appealing. :-(

Of course, it's possible that I completely misunderstand the subject, in 
which case I would love to be enlightened. :-)

Thanks!

--
Chicken Monk
"God loves ya. And she loves me too."