2 files changed, 18 insertions(+), 4 deletions(-)

M encode.rkt
M scribblings/manual.scrbl

@@ 1,8 1,12 @@
 #lang racket/base
 
-(require racket/undefined
+(require racket/generic
+         racket/undefined
          "common.rkt")
-(provide cbor-write)
+(provide cbor-write
+         gen:cbor-custom-write
+         cbor-custom-write?
+         cbor-write-proc)
 
 (define u8-max #xFF)
 (define u16-max #xFFFF)


@@ 115,6 119,15 @@
         (write-byte (combine 7 24) out)
         (write-byte inner out))))
 
+(define-generics cbor-custom-write
+  (cbor-write-proc cbor-custom-write))
+
+(define (cbor-write-custom-impl config v out)
+  (define ser (cbor-write-proc v))
+  (unless (cbor-tag? ser)
+    (error "Custom CBOR write implementation must return a cbor-tag?"))
+  (cbor-write-tag config ser out))
+
 (define (cbor-write config v [out (current-output-port)])
   (cond
     [(and (exact-integer? v) (<= 0 v u64-max))


@@ 133,8 146,9 @@
     [(vector? v) (cbor-write-vector config v out)]
     [(hash? v) (cbor-write-map config v out)]
     [(sequence? v) (cbor-write-seq config v out)]
-    [(cbor-tag? v) (cbor-write-tag config v out)] ; todo handle interpreted values
+    [(cbor-tag? v) (cbor-write-tag config v out)]
     [(cbor-simple-value? v) (cbor-write-simple-value v out)]
+    [(cbor-custom-write? v) (cbor-write-custom-impl config v out)]
     [else (error "Don't know how to write" v)]))
 
 (module* test #f

@@ 70,7 70,7 @@ Equivalent to @racket[(or/c (integer-in 0 19) (integer-in 32 255))].
 
 @defstruct[cbor-tag ([number cbor-valid-tag-number?] [content any/c])]{
 Raw representation of a CBOR tag with tag number @racket[number] and tag content
-@racket[content].
+@racket[content]. @racket[content] must be serializable by @racket[cbor-write].
 }
 
 @defstruct[cbor-simple-value ([inner cbor-unassigned-simple-value?])]{