From a7a25f92fe4517d285b24da9f48cc8b0dacb63c8 Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Thu, 21 Apr 2022 10:46:21 +0200
Subject: [PATCH] Type random-boolean-table.

---
 functions.rkt               | 36 ++++++++++++++++++++----------------
 scribblings/functions.scrbl |  8 ++++++++
 2 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/functions.rkt b/functions.rkt
index 07385df..7a062c1 100644
--- a/functions.rkt
+++ b/functions.rkt
@@ -24,7 +24,8 @@
    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-functions
-   enumerate-boolean-functions/pv enumerate-boolean-functions/list)
+   enumerate-boolean-functions/pv enumerate-boolean-functions/list
+   random-boolean-table)
 
   (module+ test
     (require typed/rackunit))
@@ -311,6 +312,22 @@
       (check-false (bool-f1/list '(#f)))
       (check-false (bool-f1/list '(#t)))))
 
+  (: random-boolean-table (-> Integer (Listof (Listof Boolean))))
+  (define (random-boolean-table n)
+    (define ins (boolean-power n))
+    (define outs (stream-take (in-random 2) (cast (expt 2 n) Nonnegative-Integer)))
+    (for/list ([i ins] [o outs])
+      (append i (list (if (= o 1) #t #f)))))
+
+  (module+ test
+    (test-case "random-boolean-table"
+      (random-seed 1)
+      (check-equal? (random-boolean-table 2)
+                    '((#f #f #t)
+                      (#f #t #t)
+                      (#t #f #f)
+                      (#t #t #t)))))
+
   (module untyped racket
     (module+ test
       (require rackunit))
@@ -394,7 +411,8 @@
  tabulate*/pv/01 tabulate/pv/01
  table->function/list table->function table->function/pv
  enumerate-boolean-tables enumerate-boolean-functions
- enumerate-boolean-functions/pv enumerate-boolean-functions/list)
+ enumerate-boolean-functions/pv enumerate-boolean-functions/list
+ random-boolean-table)
 
 (require (rename-in (submod 'typed untyped)
                     [tabulate tabulate/untyped]
@@ -406,7 +424,6 @@
   [struct tbf ((weights (vectorof number?)) (threshold number?))])
  ;; Functions
  (contract-out
-  [random-boolean-table (-> number? (listof (*list/c boolean? boolean?)))]
   [random-boolean-function (-> number? procedure?)]
   [random-boolean-function/list (-> number? procedure?)]
   [tbf-w (-> tbf? (vectorof number?))]
@@ -435,19 +452,6 @@
 ;;; Random functions
 ;;; ================
 
-;;; Generates a random truth table for a Boolean function of arity n.
-(define (random-boolean-table n)
-  (define/match (num->bool x) [(0) #f] [(1) #t])
-  (define inputs (boolean-power n))
-  (define outputs (stream-take (in-random 2) (expt 2 n)))
-  (for/list ([i inputs] [o outputs])
-    (append i (list (num->bool o)))))
-
-(module+ test
-  (test-case "random-boolean-table"
-    (random-seed 0)
-    (check-equal? (random-boolean-table 2) '((#f #f #t) (#f #t #t) (#t #f #f) (#t #t #f)))))
-
 ;;; Generates a random Boolean function of arity n.
 (define random-boolean-function (compose table->function random-boolean-table))
 
diff --git a/scribblings/functions.scrbl b/scribblings/functions.scrbl
index afa64af..cea242e 100644
--- a/scribblings/functions.scrbl
+++ b/scribblings/functions.scrbl
@@ -340,6 +340,14 @@ their arguments as a single list.
 
 @section{Random functions}
 
+@defproc[(random-boolean-table [n Integer]) (Listof (Listof Boolean))]{
+
+Generates a random truth table for a Boolean function of arity @racket[n].
+
+@examples[#:eval functions-evaluator
+(random-boolean-table 2)
+]}
+
 @section{Threshold Boolean functions}
 
 @section[#:tag "fuctions/untyped"]{Untyped definitions}