Moved debugger invocation to main submodule

tm/expander.rkt

@@ -56,7 +56,8 @@
           #:when (tm-label? (tm-line-cmd line)))
       (let ([name (tm-label-name (tm-line-cmd line))])
         (if (hash-has-key? labels-set name)
-          (error (format "Label name ~v already defined in line ~a" name (hash-ref labels-set name)))
+          (raise-user-error
+           (format "Label name ~v already defined in line ~a" name (hash-ref labels-set name)))
           (hash-set! labels-set name (tm-line-number line)))))
 
     ; Build the label table
@@ -68,7 +69,7 @@
     (define start-line-no
       (hash-ref label-table "Start"
                 (λ ()
-                  (error "This program is missing a \"Start\" label"))))
+                  (raise-user-error "This program is missing a \"Start\" label"))))
     (define raw-end-line-no
       (tm-line-number (last raw-prgm)))
     (define end-line-no
@@ -86,7 +87,7 @@
                      [(tm-if? cmd)
                       (tm-goto-dest (tm-if-cmd cmd))])])
         (when (not (hash-has-key? labels-set dest))
-          (error (format "Goto statement (in line ~a) references undefined label ~v"
+          (raise-user-error (format "Goto statement (in line ~a) references undefined label ~v"
                          (tm-line-number line) dest)))))
 
     ; Return the interpreter object
@@ -112,8 +113,8 @@
      (define raw-prgm (list STMTS ...))
      (define this-tm
        (make-tm-config raw-prgm))
-     (display "Input string: ")
-     (define input (read-line))
-     (set-input! this-tm input)
-     (simulate this-tm)))
-
+     (module+ main
+       (display "Input string: ")
+       (define input (read-line))
+       (set-input! this-tm input)
+       (simulate this-tm))))