block.rkt

#lang racket

(require
  (for-syntax
   ee-lib
   syntax/parse))

(begin-for-syntax
  (define lift-binds! (make-parameter #f))
  (define lift-syntaxes! (make-parameter #f))
  (define lift-expression! (make-parameter #f)))

(define-syntax (block stx)
  (syntax-parse stx
    [(_ body ...)
     (define defs '())
     (define stxs '())
     (define tail-exprs '())

     (define (this-lift-binds! binders e)
       )
     (define (this-lift-syntaxes! binders e)
       )
     (define (this-lift-expression! e)
       )
     
     (ee-lib-boundary
      (parameterize ([lift-binds! this-lift-binds!]
                     [lift-syntaxes! this-lift-syntaxes!]
                     [lift-expression! this-lift-expression!])
        (let loop ([todo (syntax->list #'(body ...))])
          (unless (null? todo)
            (define expanded (local-expand (first todo)
                                           (list (current-ctx-id))
                                           (list #'begin #'define-syntaxes #'define-values)
                                           (cons (current-def-ctx) (current-local-def-ctxs))))
            (syntax-parse expanded
              #:literals (begin define-syntaxes define-values)
              [(begin e ...)
               (loop (append (syntax->list #'(e ...)) todo))]
              [(define-values (x ...) e)
               (lift-binds! #'(x ...) #'e)]
              [(define-syntaxes (x ...) e)
               (lift-syntaxes! #'(x ...) #'e)]
              [e
               (lift-expression! #'e)])))
          ))]))