gistfile1.txt

#lang at-exp racket/unit

(require drracket/tool
         racket/port
         racket/format
         racket/class)

(import drracket:tool^)
(export drracket:tool-exports^)

(define inp
  (open-input-string
   (~a "#lang racket\n"
       (apply
        ~s
        '((define-syntax (f stx)
            (syntax-case stx ()
              [(_ a b)
               (begin
                 (error "Shouldn't be an internal error")
                 #'(list 'a 'b))]))
          (f 3 blue))))))

(define (def-mixin super%)
  (class super%
    (inherit get-next-settings)
    (super-new)
    (parameterize ([current-namespace (make-empty-namespace)])
      (drracket:eval:expand-program inp
                                    (get-next-settings)
                                    #t
                                    void
                                    void
                                    (λ (data next)
                                      (writeln data)
                                      (next))))))

(define (phase1) (void))
(define (phase2) (void))
(drracket:get/extend:extend-definitions-text def-mixin)