README.md

TL;DR

;;; test.sld
(define-library (foo bar)
  (import (scheme base))
  (begin
    (define x 1)
    (let ((y 2))
      (+ x y))))

$ make
$ ./r7expander.scm -l test.sld
(begin
  (define foo.bar:x 1)
  ((lambda (%y.0) (+ foo.bar:x %y.0)) 2))
>

r7expander: a macro expander for R7RS

r7expander is a macro expander for R7RS. This expander implements an expander for R7RS macros and libraries. Given a r7rs program or library, it will

1. resolve library import sets and manage export sets,
2. rename local/global variables, and
3. expand all macros.

r7expander is inspired by Al Petrosky's alexpander. Similarly to his system, r7expander is a simple data-in data-out program. Some differences are listed below:

• Main part of the program is implemented as reusable R7RS libraries.
• It deals with the library system.
• Technically, it uses syntactic closures as basic blocks of hygienic expansion.

Produced programs will be valid R5RS programs that may contain R5RS primitives

• function calls, variables, constants,
• if, quote, set!, lambda, define (only binary ones), begin,

together with

• parameterize,
• define-record-type, and
• case-lambda.

Internal definitions are not translated into letrec* because outputs can have internal define-record-type, which we don't know how to expand into internal (ordinary) definitions.

Implementation notes

Non-standard built-in libraries listed below:

• (r7expander builtin) exports basic keywords such as define and lambda.
• (r7expander native) exports all native procedures available.

License

^{Licensed under MIT license.}
_{Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in r7expander by you shall be licensed as above, without any additional terms or conditions.}