simplify runtime config

beautiful-racket-demo/basic-demo-3/expander.rkt

@@ -15,8 +15,7 @@
     #'(#%module-begin
        (module configure-runtime br
          (require "runtime.rkt")
-         (current-basic-port (current-output-port))
-         (configure-repl!))
+         (configure-this!))
        (require REQ-SPEC) ...
        (define VAR-ID 0) ...
        (provide VAR-ID ...)
@@ -24,8 +23,7 @@
        LINE ...
        (define line-table
          (apply hasheqv (append (list NUM LINE-FUNC) ...)))
-       (parameterize ([current-output-port
-                       (or (current-basic-port) (open-output-nowhere))])
+       (parameterize ([current-output-port (basic-output-port)])
          (void (run line-table))))))
 
 (begin-for-syntax

beautiful-racket-demo/basic-demo-3/runtime.rkt

@@ -1,10 +1,12 @@
 #lang br
 (require "parser.rkt" "tokenizer.rkt")
-(provide current-basic-port configure-repl!)
+(provide basic-output-port configure-this!)
 
-(define current-basic-port (make-parameter #f))
+(define basic-output-port (make-parameter (open-output-nowhere)))
+
+(define (configure-this!)
+  (basic-output-port (current-output-port))
   
-(define (configure-repl!)
   (define statement-parser (make-rule-parser b-statement))
   (define (read-one-line path port)
     (define one-line (read-line port))