.

flexible-with.rkt

@@ -13,10 +13,9 @@
        <→τ>
        <define-replace-in-tree>
        <convert-fields>
-       <τ-with-fields>
+       <τ-tree-with-fields>
        <convert-from-struct>
        <mk>
-       <utils>
        <example>]
 
 @CHUNK[<→τ>
@@ -78,12 +77,11 @@
          ;(displayln (syntax->datum #`#,(f 1)))
          (f 1))]
 
-@CHUNK[<τ-with-fields>
-       (define-for-syntax (τ-tree-with-fields fields all-fields)
+@CHUNK[<τ-tree-with-fields>
+       (define-for-syntax (τ-tree-with-fields fields all-fields2)
          (define/with-syntax (fl …) fields)
-         (define/with-syntax (field …) all-fields)
-         (let-values ([(all-fields depth-above offset i*-above names τ*)
-                       (utils #'(field …))])
+         (define/with-syntax (field …) all-fields2)
+         <utils>
          ;; Like in convert-from-struct
          (define lookup
            (make-free-id-table
@@ -110,7 +108,7 @@
                    (begin
                      `(Pairof ,(f (* i 2))
                               ,(f (add1 (* i 2))))))))
-           (f 1)))]
+         (f 1))]
 
 @CHUNK[<convert-from-struct>
        (define-for-syntax (convert-from-struct
@@ -141,8 +139,8 @@
        (define-for-syntax (mk stx)
          (syntax-case stx ()
            [(bt-fields-id (field …) [struct struct-field …] …)
-            (let-values ([(all-fields depth-above offset i*-above names τ*)
-                          (utils #'(field …))])
+            (let ()
+              <utils>
               (define total-nb-functions (vector-length names))
               #`(begin
                   (define-type-expander (bt-fields-id stx)
@@ -158,25 +156,16 @@
                           (syntax->list #'([struct-field …] …)))))]))]
 
 @CHUNK[<utils>
-       (define-for-syntax (utils stx)
-         (syntax-case stx ()
-           [(field …)
-            (let* ([all-fields #'(field …)]
-                   [depth-above (ceiling-log2 (length (syntax->list #'(field …))))]
-                   [offset (expt 2 depth-above)]
-                   [i*-above (range 1 (expt 2 depth-above))]
-                   [names (list->vector
+       (define all-fields #'(field …))
+       (define depth-above (ceiling-log2 (length (syntax->list #'(field …)))))
+       (define offset (expt 2 depth-above))
+       (define i*-above (range 1 (expt 2 depth-above)))
+       (define names (list->vector
                (append (map (λ (i) (format-id #'here "-with-~a" i))
                             i*-above)
                        (stx-map (λ (f) (format-id f "with-~a" f))
-                                            #'(field …))))]
-                   [τ* (map #λ(format-id #'here "τ~a" %) (range (add1 depth-above)))])
-              (values all-fields
-                      depth-above
-                      offset
-                      i*-above
-                      names
-                      τ*))]))]
+                                #'(field …)))))
+       (define τ* (map #λ(format-id #'here "τ~a" %) (range (add1 depth-above))))]
 @CHUNK[<example>
        (define-syntax (gs stx)
          (syntax-case stx ()