Type enumerate-boolean-functions.

functions.rkt

@@ -15,12 +15,15 @@
            (only-in typed/racket/unsafe unsafe-provide)
            (for-syntax syntax/parse))
 
+  (require/typed racket/stream
+    [stream-map (All (a b) (-> (-> a b) (Sequenceof a) (Sequenceof b)))])
+
   (provide
    pseudovariadic-lambda pvλ pseudovariadic-define pvdefine
    tabulate* tabulate*/strict tabulate*/pv tabulate tabulate/strict tabulate/pv
    tabulate*/pv/boolean tabulate/pv/boolean tabulate*/pv/01 tabulate/pv/01
    table->function/list table->function table->function/pv
-   enumerate-boolean-tables)
+   enumerate-boolean-tables enumerate-boolean-functions)
 
   (module+ test
     (require typed/rackunit))
@@ -275,6 +278,16 @@
                       ((#f #f #t) (#f #t #t) (#t #f #t) (#t #t #f))
                       ((#f #f #t) (#f #t #t) (#t #f #t) (#t #t #t))))))
 
+  (: enumerate-boolean-functions (-> Integer (Sequenceof (-> Boolean * Boolean))))
+  (define (enumerate-boolean-functions n)
+    (stream-map (inst table->function Boolean) (enumerate-boolean-tables n)))
+
+  (module+ test
+    (test-case "enumerate-boolean-functions"
+      (define bool-f1 (stream-first (enumerate-boolean-functions 1)))
+      (check-false (bool-f1 #f))
+      (check-false (bool-f1 #t))))
+
   (module untyped racket
     (module+ test
       (require rackunit))
@@ -357,7 +370,7 @@
  tabulate*/pv/boolean tabulate/pv/boolean
  tabulate*/pv/01 tabulate/pv/01
  table->function/list table->function table->function/pv
- enumerate-boolean-tables)
+ enumerate-boolean-tables enumerate-boolean-functions)
 
 (require (rename-in (submod 'typed untyped)
                     [tabulate tabulate/untyped]
@@ -369,7 +382,6 @@
   [struct tbf ((weights (vectorof number?)) (threshold number?))])
  ;; Functions
  (contract-out
-  [enumerate-boolean-functions (-> number? (stream/c procedure?))]
   [enumerate-boolean-functions/list (-> number? (stream/c procedure?))]
   [random-boolean-table (-> number? (listof (*list/c boolean? boolean?)))]
   [random-boolean-function (-> number? procedure?)]
@@ -400,18 +412,6 @@
 ;;; Constructing functions
 ;;; ======================
 
-;;; Returns the stream of all Boolean functions of a given arity.
-;;;
-;;; There are 2^(2^n) Boolean functions of arity n.
-(define (enumerate-boolean-functions n)
-  (stream-map table->function (enumerate-boolean-tables n)))
-
-(module+ test
-  (test-case "enumerate-boolean-tables"
-    (define f1 (stream-first (enumerate-boolean-functions 1)))
-    (check-false (f1 #f))
-    (check-false (f1 #t))))
-
 ;;; Returns the stream of all Boolean functions of a given arity.  As
 ;;; different from the functions returned by
 ;;; enumerate-boolean-functions, the functions take lists of arguments

scribblings/functions.scrbl

@@ -303,6 +303,17 @@ There are @tt{2^(2^n)} Boolean functions of arity @racket[n].
 (stream->list (enumerate-boolean-tables 1))
 ]}
 
+@defproc[(enumerate-boolean-functions [n Integer])
+				      (Sequenceof (-> Boolean * Boolean))]{
+
+Returns the stream of all Boolean functions of a given arity @racket[n].
+
+There are @tt{2^(2^n)} Boolean functions of arity @racket[n].
+
+@examples[#:eval functions-evaluator
+(length (stream->list (enumerate-boolean-functions 2)))
+]}
+
 @section{Random functions}
 
 @section{Threshold Boolean functions}