compilation enviroments are always modules; simplifications & refactorings
* module/ice-9/boot-9.scm (make-fresh-user-module): New public function,
makes an anonymous beautified module.
* module/language/objcode/spec.scm: We used to have some things in here
that allowed lexical variable names and values to be a part of the
environment, but no more. Now an environment is just a module. If you
want to "inject" free variables into code, just use lambda.
* module/language/scheme/compile-tree-il.scm (compile-tree-il): Same
here. Also, rely on the fact that an environment *will* be a module --
because (system base compile) guarantees that for us.
* module/language/scheme/spec.scm (scheme): In the reader, rely on the
environment being a module. Define a #:make-default-environment
handler, which returns a beautified module, augmented with a fresh
definition for current-reader, so that side effects to current-reader
are restricted to the compilation unit.
* module/language/tree-il/analyze.scm
(report-possibly-unbound-variables):
* module/language/tree-il/compile-glil.scm (compile-glil):
* module/language/tree-il/optimize.scm (optimize!): The environment will
be a module.
* module/system/base/language.scm (<language>): New field,
`make-default-environment'. Defaults to `make-fresh-user-module'.
(default-environment): New accessor, returns a default environment for
a language.
* module/system/repl/common.scm (repl-compile): Always compile relative
to the current module, because a module is always acceptable as an
environment.
* module/system/base/compile.scm (compile-file, compile-and-load): Both
of these have a new keyword argument, #:env. For `compile-file', it
defaults to the default environment of the source language, and for
`compile-and-load', to the current module.
(read-and-compile): If there are no expressions read, pass the joiner
its default environment (via `default-environment joint').