private/define-expanders.scrbl

@@ -23,7 +23,6 @@ expanders for use with other macros.
    environment}
  @item{@code{expand-all-id-expanders} - a procedure bound at phase
    @; TODO: expand-all-expanders-of-type is not documented
-   level 1 that's equivalent to
-   @racket[expand-syntax-tree-with-expanders-of-type] with the
-   @code{id-expander-type} as the type argument}
+   level 1 that's equivalent to @racket[expand-all-expanders-of-type] with
+   the @code{id-expander-type} as the type argument}
  ]}

private/expanders.rkt

@@ -4,14 +4,16 @@
          syntax/parse
          syntax/stx
          predicates
-         fancy-app
-         racket/syntax)
+         fancy-app)
 
 (provide (struct-out expander)
          (contract-out
           [expander-of-type? (-> expander-type? expander? boolean?)]
           [expand-syntax-tree-with-expanders-of-type (-> expander-type? syntax? syntax?)]))
 
+(define (maybe-syntax-local-value stx)
+  (syntax-local-value stx (λ () #f)))
+
 (struct expander (type transformer))
 
 (define (expander-of-type? type expander)
@@ -20,12 +22,12 @@
 (define (expander-stx? v)
   (and (syntax? v)
        (syntax-parse v
-         [(id:id . _) (syntax-local-value/record #'id expander?)]
+         [(id:id . _) (expander? (maybe-syntax-local-value #'id))]
          [_ #f])))
 
 (define (expander-stx->expander expander-stx)
   (syntax-parse expander-stx
-    [(id:id . _) (syntax-local-value/record #'id expander?)]))
+    [(id:id . _) (maybe-syntax-local-value #'id)]))
 
 (define (expander-stx-of-type? type v)
   (and (expander-stx? v)
@@ -45,7 +47,6 @@
 
 (define (expand-syntax-tree-with-expanders-of-type type stx)
   (define not-expander-stx-of-type? (not? (expander-stx-of-type? type _)))
-  (with-disappeared-uses 
   (expand-syntax-tree not-expander-stx-of-type?
                       call-expander-transformer
-                       stx)))
+                      stx))

test/test-arrows.rkt

@@ -1,13 +0,0 @@
-#lang racket
-(require generic-syntax-expanders rackunit)
-(define-expander-type foo)
-(define-foo-expander foo1 (λ _ #''ok))
-(define-syntax (bar stx)
-  (syntax-case stx ()
-    [(_ body)
-     (expand-all-foo-expanders #'body)]))
-;; When hovering "foo1" in the code below with the mouse, an arrow should 
-;; be shown in DrRacket from the foo1 in (define-foo-expander foo1 …) above.
-;; This is not automatically checked, as it would be difficult/brittle to check
-;; for the syntax property. Patches welcome.
-(check-equal? (bar (foo1)) 'ok)