sample-loader.rkt

#lang racket
(require (for-syntax racket))

(define-syntax (sample stx)
  (syntax-case stx (file)
    ((_ (file path))
     (let ((file (syntax->datum #'path)))
       (call-with-input-string
        (file->string file)
        (lambda (port) (read-syntax file port)))))))

(sample (file "./sample.rkt"))

; ./sample.rkt::2: say-hello: unbound identifier;
;  also, no #%app syntax transformer is bound
;   at: say-hello
;   in: (say-hello)
;   Source locations:
;   ./sample.rkt:1:0

sample.rkt

(say-hello)