compile-file and enviornments

[Matt Wette]

Hi All,

I'm a bit lost on understanding the language compiler.  One provides a lang
spec that, at minimum, specifies a reader and a compiler.  Say my reader is
read-jvs and my compiler (to Tree-IL) is comp:jvs->til.  I will call the
compiler from Tree-IL to CPS comp:til->cps, and the compiler from CPS to
bytecode comp:cps->bc.  IIRC, compile-file finds the highest level intermediate
langauage, the joint, that is able to join compiled expressions (e.g., for
Scheme this is `begin').  It then reads and compiles one expression at a time
down to the joint, combines the expressions together and then compiles to
the target (e.g., bytecode).

Now the compile routine takes an expression, an environment and options
and compiles to a triple: expression environment and continuation enviroment.
Assume the chain from JVS to bytecode is JVS->Tree-IL->CPS->BC, and that
CPS is the joint. (It's actually Tree-IL, but let's roll with CPS for now.)
My understanding is that the sequence of calls is as follows.

(let*-values
  ((jvs-c0) (jvs-def-env))
  ;;
  ((til-x1 til-e1 jvs-c1) (comp:jvs->til (read-jvs port jvs-c0) jvs-c0))
  ((cps-x1 cps-e1 til-c1) (comp:til->cps til-x1 til-e1))
  ;;
  ((til-x2 til-e2 jvs-c2) (comp:jvs->til (read-jvs port jvs-c1) jvs-c1))
  ((cps-x2 cps-e2 til-c2) (comp:til->cps til-x2 til-e2))
  ;;
  ((exps) (cps-joiner (list cps-x1 cps-x2) cps-e2)
  ((bc bc-e5 cps-c1) (comp:cps->byt exps cps-e2))
 bc)

For each compile step, I'm thinking the continuation enviornment return
value is only used for subsequent calls to the same stage of the compiler.
Did I miss it?  (See system/base/compile.scm.)

Now my problem.  I'm not using a module-env for my continuation env, I'm
using an a-list.  The compilations go fine but after combining expressions
in a file the joint-to-bytecode compilation bombs with error on unrecognzied
env.  I would not think my top-level continuation envornment should be passed
to the low level compiler.  Hmm...

The reason I want to do this is that I want to track what top-level variables
I am generating.  Remember that no `(define a 1)' expressions are being
executed to update the environment.  So I want to keep track somehow.

Matt