Enable the use-function-output-syntax option for ISL and plus. Fixes …

…#208.

The printer for ISL, ISL+ and ASL relies on use-named/undefined-handler
and named/undefined-handler to correctly print named lambdas.
In particular, use-named/undefined-handler checks whether the option
use-function-output-syntax is set.

If use-function-output-syntax is not enabled, then during module
instantiation, user-written functions like my-add1 would be printed differently.
This also affects the error message from the check-expects.

    #lang htdp/isl+
    (define (my-add1 n) (+ n 1))
    my-add1
    (check-expect my-add1 2)

Output:

    Welcome to DrRacket.
    (lambda (a1) ...)

    Ran 1 test.
    0 tests passed.

    check-expect ... error ... :: first argument of equality cannot
    be a function, given (lambda (a1) ...)

    > my-add1
    my-add1

htdp-lib/htdp/bsl/runtime.rkt

@@ -86,10 +86,11 @@
      (and (sl-runtime-settings-use-function-output-syntax? settings)
           (procedure? x)
           (object-name x))))
+  ;; The ISL case -- sl-runtime-settings-output-function-instead-of-lambda? --
+  ;; is already covered by the current-print-convert-hook above.
   (named/undefined-handler
    (lambda (x)
-     (string->symbol
-      (format "function:~a" (object-name x)))))
+     (object-name x)))
 
   ; sharing done by print-convert
   (show-sharing (sl-runtime-settings-show-sharing? settings))

htdp-lib/lang/private/teach-module-begin.rkt

@@ -184,11 +184,14 @@
                         output-function-instead-of-lambda))
      (mk-module-begin '(abbreviate-cons-as-list
                         read-accept-quasiquote
+                        use-function-output-syntax
                         output-function-instead-of-lambda))
      (mk-module-begin '(abbreviate-cons-as-list
-                        read-accept-quasiquote))
+                        read-accept-quasiquote
+                        use-function-output-syntax))
      (mk-module-begin '(abbreviate-cons-as-list
                         read-accept-quasiquote
+                        use-function-output-syntax
                         show-sharing))
 
      ;; module-continue