Add an easy type to variable-mapping? and remove the untyped section.

utils.rkt

@@ -26,7 +26,9 @@
    collect-by-key/sets ht-values/list->set hash->list/ordered
    multi-split-at lists-transpose in-random cartesian-product-2/stream
    cartesian-product/stream boolean-power boolean-power/stream any->01
-   01->boolean)
+   01->boolean
+
+   variable-mapping?)
 
   (define-type Variable Symbol)
   (define-type (VariableMapping A) (Immutable-HashTable Variable A))
@@ -560,6 +562,13 @@
     (test-case "01->boolean"
       (check-equal? (01->boolean 0) #f)
       (check-equal? (01->boolean 1) #t)))
+
+  ;; TODO: Remove when the other modules are converted to Typed Racket
+  ;; and these contracts are not needed any more.
+
+  (: variable-mapping? (-> Any Boolean : HashTableTop))
+  (define (variable-mapping? dict)
+    (hash? dict))
   )
 
 (require 'typed)
@@ -572,26 +581,6 @@
          collect-by-key/sets ht-values/list->set hash->list/ordered
          multi-split-at lists-transpose in-random cartesian-product-2/stream
          cartesian-product/stream boolean-power boolean-power/stream any->01
-         01->boolean)
+         01->boolean
 
-;;; Untyped section.
+         variable-mapping?)
-
-(provide
- ;; Contracts
- (contract-out [variable-mapping? contract?]
-               [string-variable-mapping? contract?]
-               [general-pair/c (-> contract? contract? contract?)]))
-
-(module+ test
-  (require rackunit))
-
-
-(define (variable-mapping? dict) (hash/c symbol? any/c))
-
-;;; A string variable mapping is a mapping from variables to strings.
-(define (string-variable-mapping? dict) (hash/c symbol? string?))
-
-;;; A contract allowing pairs constructed via cons or via list.
-(define (general-pair/c key-contract val-contract)
-  (or/c (list/c key-contract val-contract)
-        (cons/c key-contract val-contract)))