Provide built-in `computer' record type for DMdA.

`chocolate-cookie' has been wildly unpopular, so we'll try this next semester.

Also, clean up the `provide' forms for the chocolate cookies.

collects/deinprogramm/DMdA-advanced.rkt

@@ -12,8 +12,7 @@
 	 check-expect check-within check-error check-member-of check-range
 	 check-property for-all ==> expect expect-within expect-member-of expect-range
 	 signature contract : define-contract -> mixed one-of predicate combined list-of
-	 number real rational integer natural boolean true false string symbol empty-list unspecific property
+	 number real rational integer natural boolean true false string symbol empty-list unspecific property)
-	 chocolate-cookie)
 (provide cons)
 (provide-and-document
  procedures

collects/deinprogramm/DMdA-assignments.rkt

@@ -12,8 +12,7 @@
 	 check-expect check-within check-error check-member-of check-range
 	 check-property for-all ==> expect expect-within expect-member-of expect-range
 	 signature contract : define-contract -> mixed one-of predicate combined list-of
-	 number real rational integer natural boolean true false string empty-list unspecific property
+	 number real rational integer natural boolean true false string empty-list unspecific property)
-	 chocolate-cookie)
 (provide cons)
 (provide-and-document
  procedures

collects/deinprogramm/DMdA-beginner.rkt

@@ -8,8 +8,7 @@
 	 check-expect check-within check-error check-member-of check-range
 	 check-property for-all ==> expect expect-within expect-member-of expect-range
 	 signature contract : define-contract -> mixed one-of predicate combined
-	 number real rational integer natural boolean true false string empty-list property
+	 number real rational integer natural boolean true false string empty-list property)
-	 chocolate-cookie)
 (provide cons list)
 (provide-and-document
  procedures

collects/deinprogramm/DMdA-vanilla.rkt

@@ -8,8 +8,7 @@
 	 check-expect check-within check-error check-member-of check-range
 	 check-property for-all ==> expect expect-within expect-member-of expect-range
 	 signature contract : define-contract -> mixed one-of predicate combined list-of
-	 number real rational integer natural boolean true false string empty-list property
+	 number real rational integer natural boolean true false string empty-list property)
-	 chocolate-cookie)
 (provide cons)
 (provide-and-document
  procedures

collects/deinprogramm/DMdA.rkt

@@ -37,7 +37,6 @@
 	 boolean true false
 	 string symbol
 	 empty-list
-	 chocolate-cookie
 	 unspecific
 	 property)
 
@@ -274,7 +273,23 @@
   (reverse ((list %a)  -> (list %a))
 	   "Liste in umgekehrte Reihenfolge bringen"))
 
+ ("Computer"
+  (computer signature
+	    "Signatur für Computer")
+  (make-computer (string rational rational -> computer)
+		 "Computer aus Prozessorname, Arbeitsspeicher und Festplattenkapazität konstruieren")
+  (computer? (%a -> boolean)
+	     "feststellen, ob Wert ein Computer ist")
+  (computer-processor (computer -> string)
+		      "Prozessorname aus Computer extrahieren")
+  (computer-ram (computer -> rational)
+		"Arbeitsspeicher aus Computer extrahieren")
+  (computer-hard-drive (computer -> rational)
+		       "Festplattenkapazität aus Computer extrahieren"))
+
  ("Schokokekse"
+  (chocolate-cookie signature
+		    "Signatur für Schokokekse")
   (make-chocolate-cookie (number number -> chocolate-cookie)
 			 "Schokokeks aus Schoko- und Keks-Anteil konstruieren")
   (chocolate-cookie? (%a -> boolean)
@@ -850,6 +865,12 @@
   make-chocolate-cookie chocolate-cookie?
   (chocolate-cookie-chocolate chocolate-cookie-cookie))
 
+(define-record-procedures computer
+  make-computer computer?
+  (computer-processor
+   computer-ram
+   computer-hard-drive))
+
 (define (violation text)
   (error text))