Invoke `racket` in a Racket script

Question

General question:

Can I invoke the current racket executable from within a running Racket script?

Basically, I'd like a replacement for (system "racket ...") in the case that (find-executable-path "racket") does not return a path to the Racket executable I'm currently using.

Context:

What I really want is to try compiling a few expressions and assert that they raise compilation errors. This is for unit testing.

Answer 1

I don't believe you need to step outside of the executable here. Try this:

#lang racket

(require syntax/modread)

;; define a namespace anchor to attach a namespace to:
(define-namespace-anchor anchor)
;; define a namespace for expansion:
(define target-namespace (namespace-anchor->namespace anchor))

(define program-to-compile
  "#lang racket
(+ 3 4)")

;; go ahead and expand
(with-module-reading-parameterization
 (λ()
   (parameterize ([current-namespace target-namespace])
   (expand
    (read-syntax
     "bogus-filename"
     (open-input-string program-to-compile))))))

I think I'm correct when I say that Racket is singularly clean in its ability to provide the compiler to running programs in a disciplined way.

Answer 2

If your goal is just to compile some racket expressions, you can do that just with either compile or compile-syntax. An example file would be:

#lang racket
(require rackunit)

(define tests
  (list #'(+ 1 "3")
        #'(void void)
        #'(string-append 4)))

(for/list ([t (in-list test)])
  (check-exn exn:fail?
     (lambda () (compile t))))

Where exn:fail? is whatever exception you are looking for.

Furthermore, if you have some common syntax context you want to run your test in, you can use #` #,. So your code would end up something like this:

#lang racket
(require rackunit)

(define tests
  (list #'(+ 1 "3")
        #'(void void)
        #'(string-append 4)))

(for/list ([t (in-list test)])
  (check-exn exn:fail?
     (lambda () (compile #`(module anonymous racket
                             #,t)))))

Finally, if your code is stored on your computer, you can use John's solution, while using file->string to convert the file into a string.