add example for subtract-in

svn: r14599

collects/scribblings/reference/syntax.scrbl

@@ -998,7 +998,29 @@ monkey
 
 @defform[(subtract-in require-spec subtracted-spec ...)]{ Like
   @scheme[require-spec], but omitting those imports that would be
-  imported by one of the @scheme[subtracted-spec]s.}
+  imported by one of the @scheme[subtracted-spec]s.
+
+@defexamples[#:eval (syntax-eval)
+(module earth scheme
+  (provide land sea air)
+  (define land 1)
+  (define sea 2)
+  (define air 3))
+
+(module mars scheme
+  (provide aliens)
+  (define aliens 4))
+
+(module solar-system scheme
+  (require 'earth 'mars)
+  (provide (all-from-out 'earth)
+           (all-from-out 'mars)))
+
+(require scheme/require)
+(require (subtract-in 'solar-system 'earth))
+land
+aliens
+]}
 
 @defform[(filtered-in proc-expr require-spec)]{ The @scheme[proc-expr]
   should evaluate to a single-argument procedure, which is applied on