Make a grammar struct

The grammar class delegates to it for now. Eventually I'll remove the class.

parser-tools/private-yacc/grammar.rkt

@@ -137,18 +137,29 @@
 
 ;; ------------------------- Grammar ------------------------------
 
-(define grammar%
-  (class object%
-    (super-instantiate ())
 ;; prods: production list list
 ;; where there is one production list per non-term
-    (init prods)
 ;; init-prods: production list
 ;; The productions parsing can start from
 ;; nullable-non-terms is indexed by the non-term-index and is true iff non-term is nullable
-    (init-field init-prods terms non-terms end-terms)
+(struct grammar (prods
+                 init-prods
+                 terms
+                 non-terms
+                 end-terms
+                 all-prods
+                 num-prods
+                 num-terms
+                 num-non-terms
+                 nt->prods
+                 nullable-non-terms))
+
+(define (make-grammar #:prods prods
+                      #:init-prods init-prods
+                      #:terms terms
+                      #:non-terms non-terms
+                      #:end-terms end-terms)
 
-    ;; list of all productions
   (define all-prods (apply append prods))
   (define num-prods (length all-prods))
   (define num-terms (length terms))
@@ -164,31 +175,54 @@
     (set-prod-index! prod count))
 
   ;; indexed by the index of the non-term - contains the list of productions for that non-term
-    (define nt->prods
+  (define nt->prods (make-vector (length prods) #f))
-      (let ((v (make-vector (length prods) #f)))
   (for ([prods (in-list prods)])
-          (vector-set! v (non-term-index (prod-lhs (car prods))) prods))
+    (vector-set! nt->prods (non-term-index (prod-lhs (car prods))) prods))
-        v))
       
   (define nullable-non-terms
     (nullable all-prods num-non-terms))
   
-    (define/public (get-num-terms) num-terms)
+  (grammar prods
-    (define/public (get-num-non-terms) num-non-terms)
+           init-prods
+           terms
+           non-terms
+           end-terms
+           all-prods
+           num-prods
+           num-terms
+           num-non-terms
+           nt->prods
+           nullable-non-terms))
+
+(define grammar%
+  (class object%
+    (super-instantiate ())
+    (init prods init-prods terms non-terms end-terms)
+
+    (define backing-struct
+      (make-grammar
+       #:prods prods
+       #:init-prods init-prods
+       #:terms terms
+       #:non-terms non-terms
+       #:end-terms end-terms))
+            
+    (define/public (get-num-terms) (grammar-num-terms backing-struct))
+    (define/public (get-num-non-terms) (grammar-num-non-terms backing-struct))
       
     (define/public (get-prods-for-non-term nt)
-      (vector-ref nt->prods (non-term-index nt)))
+      (vector-ref (grammar-nt->prods backing-struct) (non-term-index nt)))
-    (define/public (get-prods) all-prods)
+    (define/public (get-prods) (grammar-all-prods backing-struct))
-    (define/public (get-init-prods) init-prods)
+    (define/public (get-init-prods) (grammar-init-prods backing-struct))
       
-    (define/public (get-terms) terms)
+    (define/public (get-terms) (grammar-terms backing-struct))
-    (define/public (get-non-terms) non-terms)
+    (define/public (get-non-terms) (grammar-non-terms backing-struct))
       
-    (define/public (get-num-prods) num-prods)
+    (define/public (get-num-prods) (grammar-num-prods backing-struct))
-    (define/public (get-end-terms) end-terms)
+    (define/public (get-end-terms) (grammar-end-terms backing-struct))
       
     (define/public (nullable-non-term? nt)
-      (vector-ref nullable-non-terms (non-term-index nt)))
+      (vector-ref (grammar-nullable-non-terms backing-struct) (non-term-index nt)))
 
     (define/public (nullable-after-dot? item)
       (define rhs (prod-rhs (item-prod item)))