Add table->unary-function.

functions.rkt

@@ -23,7 +23,7 @@
  tabulate*/pv/boolean tabulate/pv/boolean tabulate*/pv/01 tabulate/pv/01
  tabulate*/list tabulate/list
  tabulate*/list/boolean tabulate/list/boolean tabulate*/list/01 tabulate/list/01
- table->function/list table->function table->function/pv
+ table->function/list table->unary-function table->function table->function/pv
  enumerate-boolean-tables enumerate-boolean-functions
  enumerate-boolean-functions/pv enumerate-boolean-functions/list
  random-boolean-table random-boolean-function random-boolean-function/list
@@ -292,6 +292,19 @@
     (check-true (negation/list '(#f)))
     (check-false (negation/list '(#t)))))
 
+(: table->unary-function (All (a b) (-> (Listof (List a b)) (-> a b))))
+(define (table->unary-function table)
+  (define ht-tab
+    (for/hash ([line (in-list table)]) : (HashTable a b)
+      (values (car line) (cadr line))))
+  (λ (x) (hash-ref ht-tab x)))
+
+(module+ test
+  (test-case "table->unary-function"
+    (define unary-negation (table->unary-function '((#t #f) (#f #t))))
+    (check-false (unary-negation #t))
+    (check-true (unary-negation #f))))
+
 (: table->function (All (a) (-> (Listof (Listof a)) (-> a * a))))
 (define (table->function table)
   (define func (table->function/list table))

scribblings/functions.scrbl

@@ -344,6 +344,18 @@ last element.
 (and/list '(#t #t))
 ]}
 
+@defproc[(table->unary-function [table (Listof (List a b))])
+				(-> a b)]{
+
+Like @racket[table->function/list], but the @racket[table] contains
+exactly 2 columns: one column for the inputs and one column for the
+outputs, and the result is a unary function.
+
+@ex[
+(let ([unary-negation (table->unary-function '((#t #f) (#f #t)))])
+  (unary-negation #t))
+]}
+
 @defproc[(table->function [table (Listof (Listof a))])
 			  (-> a * a)]{