diff --git a/xenomorph/xenomorph/buffer.rkt b/xenomorph/xenomorph/bytes.rkt
similarity index 88%
rename from xenomorph/xenomorph/buffer.rkt
rename to xenomorph/xenomorph/bytes.rkt
index 13581d43..d5d29098 100644
--- a/xenomorph/xenomorph/buffer.rkt
+++ b/xenomorph/xenomorph/bytes.rkt
@@ -7,7 +7,7 @@ approximates
 https://github.com/mbutterick/restructure/blob/master/src/Buffer.coffee
 |#
 
-(define x:buffer%
+(define x:bytes%
   (class x:base%
     (super-new)
     (init-field [(@len len)])
@@ -30,10 +30,13 @@ https://github.com/mbutterick/restructure/blob/master/src/Buffer.coffee
         [#false (resolve-length @len val parent)]
         [_ (raise-argument-error 'x:buffer-size "bytes or #f" val)]))))
 
-(define (x:buffer [len-arg #f]
+(define (x:bytes [len-arg #f]
                   #:length [len-kwarg #f]
                   #:pre-encode [pre-proc #f]
                   #:post-decode [post-proc #f]
-                  #:base-class [base-class x:buffer%])
+                  #:base-class [base-class x:bytes%])
   (define len (or len-arg len-kwarg #xffff))
-  (new (generate-subclass base-class pre-proc post-proc) [len len]))
\ No newline at end of file
+  (new (generate-subclass base-class pre-proc post-proc) [len len]))
+
+(define x:buffer% x:bytes%)
+(define x:buffer x:bytes)
\ No newline at end of file
diff --git a/xenomorph/xenomorph/array.rkt b/xenomorph/xenomorph/list.rkt
similarity index 89%
rename from xenomorph/xenomorph/array.rkt
rename to xenomorph/xenomorph/list.rkt
index 31313036..64fbb8ee 100644
--- a/xenomorph/xenomorph/array.rkt
+++ b/xenomorph/xenomorph/list.rkt
@@ -11,7 +11,7 @@ approximates
 https://github.com/mbutterick/restructure/blob/master/src/Array.coffee
 |#
 
-(define x:array%
+(define x:list%
   (class x:base%
     (super-new)
     (init-field [(@type type)] [(@len len)] [(@count-bytes? count-bytes?)])
@@ -86,22 +86,26 @@ https://github.com/mbutterick/restructure/blob/master/src/Array.coffee
               (define size (send @type x:size #f parent))
               (* size count)]))))
 
-(define (x:array [type-arg #f] [len-arg #f] [length-type-arg 'count]
+(define (x:list [type-arg #f] [len-arg #f] [length-type-arg 'count]
                  #:type [type-kwarg #f]
                  #:length [len-kwarg #f]
                  #:count-bytes [count-bytes? #f]
                  #:pre-encode [pre-proc #f]
                  #:post-decode [post-proc #f]
-                 #:base-class [base-class x:array%])
+                 #:base-class [base-class x:list%])
   (new (generate-subclass base-class pre-proc post-proc) [type (or type-arg type-kwarg)]
        [len (or len-arg len-kwarg)]
        [count-bytes? count-bytes?]))
 
-(define (x:array? x) (is-a? x x:array%))
+(define (x:list? x) (is-a? x x:list%))
+
+(define x:array% x:list%)
+(define x:array x:list)
+(define x:array? x:list?)
   
 (module+ test
   (require rackunit "base.rkt")
-  (check-equal? (decode (x:array uint16be 3) #"ABCDEF") '(16706 17220 17734))
-  (check-equal? (encode (x:array uint16be 3) '(16706 17220 17734) #f) #"ABCDEF")
-  (check-equal? (size (x:array uint16be) '(1 2 3)) 6)
-  (check-equal? (size (x:array doublebe) '(1 2 3 4 5)) 40))
+  (check-equal? (decode (x:list uint16be 3) #"ABCDEF") '(16706 17220 17734))
+  (check-equal? (encode (x:list uint16be 3) '(16706 17220 17734) #f) #"ABCDEF")
+  (check-equal? (size (x:list uint16be) '(1 2 3)) 6)
+  (check-equal? (size (x:list doublebe) '(1 2 3 4 5)) 40))
diff --git a/xenomorph/xenomorph/main.rkt b/xenomorph/xenomorph/main.rkt
index febaf84f..f6e87350 100644
--- a/xenomorph/xenomorph/main.rkt
+++ b/xenomorph/xenomorph/main.rkt
@@ -4,17 +4,19 @@
 (define-syntax-rule (r+p ID ...)
   (begin (require ID ...) (provide (all-from-out ID ...))))
 
-(r+p "array.rkt"
-     "bitfield.rkt"
-     "buffer.rkt"
+(r+p "bitfield.rkt"
+     "bytes.rkt"
      "enum.rkt"
      "base.rkt"
-     "lazy-array.rkt"
+     "list.rkt"
      "number.rkt"
      "optional.rkt"
      "pointer.rkt"
      "reserved.rkt"
      "string.rkt"
+     "stream.rkt"
      "struct.rkt"
+     "symbol.rkt"
+     "vector.rkt"
      "versioned-struct.rkt"
      "util.rkt")
diff --git a/xenomorph/xenomorph/lazy-array.rkt b/xenomorph/xenomorph/stream.rkt
similarity index 84%
rename from xenomorph/xenomorph/lazy-array.rkt
rename to xenomorph/xenomorph/stream.rkt
index a14ec917..b0aa199d 100644
--- a/xenomorph/xenomorph/lazy-array.rkt
+++ b/xenomorph/xenomorph/stream.rkt
@@ -1,6 +1,6 @@
 #lang racket/base
 (require racket/class
-         "base.rkt" "util.rkt" "number.rkt" "array.rkt" racket/stream sugar/unstable/dict)
+         "base.rkt" "util.rkt" "number.rkt" "list.rkt" racket/stream sugar/unstable/dict)
 (provide (all-defined-out))
 
 #|
@@ -8,8 +8,8 @@ approximates
 https://github.com/mbutterick/restructure/blob/master/src/LazyArray.coffee
 |#
  
-(define x:lazy-array%
-  (class x:array%
+(define x:stream%
+  (class x:list%
     (super-new)
     (inherit-field [@type type] [@len len])
 
@@ -38,29 +38,32 @@ https://github.com/mbutterick/restructure/blob/master/src/LazyArray.coffee
     (define/override (x:size [val #f] [parent #f])
       (super x:size (if (stream? val) (stream->list val) val) parent))))
 
-(define (x:lazy-array [type-arg #f] [len-arg #f]
+(define (x:stream [type-arg #f] [len-arg #f]
                       #:type [type-kwarg #f]
                       #:length [len-kwarg #f]
                       #:pre-encode [pre-proc #f]
                       #:post-decode [post-proc #f]
-                      #:base-class [base-class x:lazy-array%])
+                      #:base-class [base-class x:stream%])
   (define type (or type-arg type-kwarg))
   (define len (or len-arg len-kwarg))
   (new (generate-subclass base-class pre-proc post-proc) [type type]
        [len len]
        [count-bytes? #false]))
 
+(define x:lazy-array% x:stream%)
+(define x:lazy-array x:stream)
+
 (module+ test
   (require rackunit "number.rkt" "base.rkt")
   (define bstr #"ABCD1234")
   (define ds (open-input-bytes bstr))
-  (define la (x:lazy-array uint8 4))
+  (define la (x:stream uint8 4))
   (define ila (decode la ds))
   (check-equal? (pos ds) 4)
   (check-equal? (stream-ref ila 1) 66)
   (check-equal? (stream-ref ila 3) 68)
   (check-equal? (pos ds) 4)
   (check-equal? (stream->list ila) '(65 66 67 68))
-  (define la2 (x:lazy-array int16be (λ (t) 4))) 
+  (define la2 (x:stream int16be (λ (t) 4))) 
   (check-equal? (encode la2 '(1 2 3 4) #f) #"\0\1\0\2\0\3\0\4")
   (check-equal? (stream->list (decode la2 (open-input-bytes #"\0\1\0\2\0\3\0\4"))) '(1 2 3 4)))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/string.rkt b/xenomorph/xenomorph/string.rkt
index c3fddba1..baddf6e7 100644
--- a/xenomorph/xenomorph/string.rkt
+++ b/xenomorph/xenomorph/string.rkt
@@ -89,39 +89,3 @@ https://github.com/mbutterick/restructure/blob/master/src/String.coffee
   (define len (or len-arg len-kwarg))
   (define encoding (or enc-arg enc-kwarg 'ascii))
   (new (generate-subclass base-class pre-proc post-proc) [len len] [encoding encoding]))
-
-(define x:symbol%
-  (class x:string%
-    (super-new)
-    (inherit-field len encoding)
-
-    (define/override (pre-encode val)
-      (unless (or (string? val) (symbol? val))
-        (raise-argument-error 'xsymbol-encode "symbol or string" val))
-      (if (symbol? val) (symbol->string val) val))
-    
-    (define/override (post-decode val) (string->symbol val))))
-
-(define (x:symbol [len-arg #f] [enc-arg #f]
-                  #:length [len-kwarg #f]
-                  #:encoding [enc-kwarg #f]
-                  #:pre-encode [pre-proc #f]
-                  #:post-decode [post-proc #f]
-                  #:base-class [base-class x:symbol%])
-  (define len (or len-arg len-kwarg))
-  (define encoding (or enc-arg enc-kwarg 'utf8))
-  (new (generate-subclass base-class pre-proc post-proc) [len len] [encoding encoding]))
-
-(module+ test
-  (require rackunit "base.rkt")
-  (define S-fixed (x:string 4 'utf8))
-  (check-equal? (encode S-fixed "Mike" #f) #"Mike")
-  (check-exn exn:fail? (λ () (encode S-fixed "Mikes" #f))) ; too long for fixed string 
-  (define S (x:string uint8 'utf8))
-  (check-equal? (decode S #"\2BCDEF") "BC")
-  (check-equal? (encode S "Mike" #f) #"\4Mike")
-  (check-equal? (size (x:string) "foobar") 7) ; null terminated when no len
-  (check-equal? (decode (x:symbol 4) #"Mike") 'Mike)
-  (check-equal? (encode (x:symbol 4) 'Mike #f) #"Mike")
-  (check-equal? (encode (x:symbol 4) "Mike" #f) #"Mike")
-  (check-exn exn:fail:contract? (λ () (encode (x:symbol 4) 42 #f))))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/symbol.rkt b/xenomorph/xenomorph/symbol.rkt
new file mode 100644
index 00000000..c4fa9feb
--- /dev/null
+++ b/xenomorph/xenomorph/symbol.rkt
@@ -0,0 +1,38 @@
+#lang racket/base
+(require racket/class "base.rkt" "number.rkt" "string.rkt")
+(provide (all-defined-out))
+
+(define x:symbol%
+  (class x:string%
+    (super-new)
+
+    (define/override (pre-encode val)
+      (unless (or (string? val) (symbol? val))
+        (raise-argument-error 'x:symbol-encode "symbol or string" val))
+      (if (symbol? val) (symbol->string val) val))
+    
+    (define/override (post-decode val) (string->symbol val))))
+
+(define (x:symbol [len-arg #f] [enc-arg #f]
+                  #:length [len-kwarg #f]
+                  #:encoding [enc-kwarg #f]
+                  #:pre-encode [pre-proc #f]
+                  #:post-decode [post-proc #f]
+                  #:base-class [base-class x:symbol%])
+  (define len (or len-arg len-kwarg))
+  (define encoding (or enc-arg enc-kwarg 'utf8))
+  (new (generate-subclass base-class pre-proc post-proc) [len len] [encoding encoding]))
+
+(module+ test
+  (require rackunit "base.rkt")
+  (define S-fixed (x:string 4 'utf8))
+  (check-equal? (encode S-fixed "Mike" #f) #"Mike")
+  (check-exn exn:fail? (λ () (encode S-fixed "Mikes" #f))) ; too long for fixed string 
+  (define S (x:string uint8 'utf8))
+  (check-equal? (decode S #"\2BCDEF") "BC")
+  (check-equal? (encode S "Mike" #f) #"\4Mike")
+  (check-equal? (size (x:string) "foobar") 7) ; null terminated when no len
+  (check-equal? (decode (x:symbol 4) #"Mike") 'Mike)
+  (check-equal? (encode (x:symbol 4) 'Mike #f) #"Mike")
+  (check-equal? (encode (x:symbol 4) "Mike" #f) #"Mike")
+  (check-exn exn:fail:contract? (λ () (encode (x:symbol 4) 42 #f))))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/test/array-test.rkt b/xenomorph/xenomorph/test/array-test.rkt
deleted file mode 100644
index aca4f06c..00000000
--- a/xenomorph/xenomorph/test/array-test.rkt
+++ /dev/null
@@ -1,116 +0,0 @@
-#lang racket/base
-(require rackunit
-         racket/class
-         "../array.rkt"
-         "../struct.rkt"
-         "../number.rkt"
-         "../pointer.rkt"
-         "../base.rkt"
-         sugar/unstable/dict)
-
-#|
-approximates
-https://github.com/mbutterick/restructure/blob/master/test/Array.coffee
-|#
-
-(test-case 
- "array: decode fixed length"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8 #:length 4)) '(1 2 3 4))))
-
-(test-case 
- "array: decode nested"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type (x:struct 'foo uint8) #:length 4))
-                 (list (mhasheq 'foo 1)
-                       (mhasheq 'foo 2)
-                       (mhasheq 'foo 3)
-                       (mhasheq 'foo 4)))))
-
-(test-case 
- "array: decode with post-decode"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xa (x:array #:type uint8 #:length 4 #:post-decode (λ (val) (map (λ (x) (* 2 x)) val))))
-   (check-equal? (decode xa) '(2 4 6 8))))
-
-(test-case 
- "array: decode fixed number of bytes"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint16be #:length 4 #:count-bytes #t)) '(258 772))))
-
-(test-case 
- "array: decode length from parent key"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8 #:length 'len) (current-input-port) #:parent (mhash 'len 4)) '(1 2 3 4))))
-
-(test-case 
- "array: decode byte count from parent key"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint16be #:length 'len #:count-bytes #t) (current-input-port) #:parent (mhash 'len 4)) '(258 772))))
-
-(test-case 
- "array: decode length as number before array"
- (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8 #:length uint8)) '(1 2 3 4))))
-
-(test-case 
- "array: decode byte count as number before array"
- (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint16be #:length uint8 #:count-bytes #t)) '(258 772))))
-
-(test-case 
- "array: decode length from function"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8 #:length (λ _ 4))) '(1 2 3 4))))
-
-(test-case 
- "array: decode byte count from function"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint16be #:length (λ _ 4) #:count-bytes #t)) '(258 772))))
-
-(test-case 
- "array: decode to the end of parent if no length given"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8) (current-input-port) #:parent (mhash x:length-key 4 x:start-offset-key 0)) '(1 2 3 4))))
-
-(test-case 
- "array: decode to the end of the stream if parent exists, but its length is 0"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (check-equal? (decode (x:array #:type uint8) (current-input-port) #:parent (mhash x:length-key 0 x:start-offset-key 0)) '(1 2 3 4 5))))
-
-(test-case 
- "array: decode to the end of the stream if no parent and length is given"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4))])
-   (check-equal? (decode (x:array #:type uint8)) '(1 2 3 4 ))))
-
-(test-case 
- "array: use array length"
- (check-equal? (size (x:array #:type uint8 #:length 10) '(1 2 3 4)) 4))
-
-(test-case 
- "array: add size of length field before string"
- (check-equal? (size (x:array #:type uint8 #:length uint8) '(1 2 3 4)) 5))
-
-(test-case 
- "array: use defined length if no value given"
- (check-equal? (size (x:array #:type uint8 #:length 10)) 10))
-
-(test-case 
- "array: encode using array length"
- (check-equal? (encode (x:array #:type uint8 #:length 10) '(1 2 3 4) #f) (bytes 1 2 3 4)))
-
-(test-case 
- "array: encode with pre-encode"
- (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xa (x:array #:type uint8 #:length 4 #:pre-encode (λ (val) (map (λ (x) (* 2 x)) val))))
-   (check-equal? (encode xa '(1 2 3 4) #f) (bytes 2 4 6 8))))
-
-(test-case 
- "array: encode length as number before array"
- (check-equal? (encode (x:array #:type uint8 #:length uint8) '(1 2 3 4) #f) (bytes 4 1 2 3 4)))
-
-(test-case 
-   "array: add pointers after array if length is encoded at start"
-   (check-equal? (encode (x:array #:type (x:pointer #:offset-type uint8
-                                             #:type uint8)
-                                  #:length uint8) '(1 2 3 4) #f) (bytes 4 5 6 7 8 1 2 3 4)))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/test/buffer-test.rkt b/xenomorph/xenomorph/test/bytes-test.rkt
similarity index 57%
rename from xenomorph/xenomorph/test/buffer-test.rkt
rename to xenomorph/xenomorph/test/bytes-test.rkt
index 694c0f32..4f99cee7 100644
--- a/xenomorph/xenomorph/test/buffer-test.rkt
+++ b/xenomorph/xenomorph/test/bytes-test.rkt
@@ -1,7 +1,7 @@
 #lang racket/base
 (require rackunit
          racket/class
-         "../buffer.rkt"
+         "../bytes.rkt"
          "../number.rkt"
          "../base.rkt")
 
@@ -11,53 +11,53 @@ https://github.com/mbutterick/restructure/blob/master/test/Buffer.coffee
 |#
 
 (test-case
- "buffer: should decode"
+ "bytes: should decode"
  (parameterize ([current-input-port (open-input-bytes (bytes #xab #xff #x1f #xb6))])
-   (define buf (x:buffer #:length 2))
+   (define buf (x:bytes #:length 2))
    (check-equal? (decode buf) (bytes #xab #xff))
    (check-equal? (decode buf) (bytes #x1f #xb6))))
 
 (test-case
- "buffer: should error on invalid length"
- (check-exn exn:fail:contract? (λ () (x:buffer #:length #true))))
+ "bytes: should error on invalid length"
+ (check-exn exn:fail:contract? (λ () (x:bytes #:length #true))))
 
 (test-case
- "buffer: should decode with post-decode"
+ "bytes: should decode with post-decode"
  (parameterize ([current-input-port (open-input-bytes (bytes #xab #xff #x1f #xb6))])
-   (define buf (x:buffer #:length 2 #:post-decode (λ (val) (bytes 1 2))))
+   (define buf (x:bytes #:length 2 #:post-decode (λ (val) (bytes 1 2))))
    (check-equal? (decode buf) (bytes 1 2))
    (check-equal? (decode buf) (bytes 1 2))))
 
 (test-case
- "buffer: should decode with parent key length"
+ "bytes: should decode with parent key length"
  (parameterize ([current-input-port (open-input-bytes (bytes #xab #xff #x1f #xb6))])
-   (define buf (x:buffer #:length 'len))
+   (define buf (x:bytes #:length 'len))
    (check-equal? (decode buf #:parent (hash 'len 3)) (bytes #xab #xff #x1f))
    (check-equal? (decode buf #:parent (hash 'len 1)) (bytes #xb6))))
 
 (test-case
- "buffer: hould return size"
- (check-equal? (size (x:buffer #:length 2) (bytes #xab #xff)) 2))
+ "bytes: hould return size"
+ (check-equal? (size (x:bytes #:length 2) (bytes #xab #xff)) 2))
 
 (test-case
- "buffer: hould use defined length if no value given"
- (check-equal? (size (x:buffer #:length 10)) 10))
+ "bytes: hould use defined length if no value given"
+ (check-equal? (size (x:bytes #:length 10)) 10))
 
 (test-case
- "buffer: should encode"
- (let ([buf (x:buffer 2)])
+ "bytes: should encode"
+ (let ([buf (x:bytes 2)])
    (check-equal? (bytes-append
                   (encode buf (bytes #xab #xff) #f)
                   (encode buf (bytes #x1f #xb6) #f)) (bytes #xab #xff #x1f #xb6))))
 
 (test-case
- "buffer: should encode with pre-encode"
+ "bytes: should encode with pre-encode"
  (let ()
-   (define buf (x:buffer 2 #:pre-encode (λ (val) (bytes 1 2))))
+   (define buf (x:bytes 2 #:pre-encode (λ (val) (bytes 1 2))))
    (check-equal? (bytes-append
                   (encode buf (bytes #xab #xff) #f)
                   (encode buf (bytes #x1f #xb6) #f)) (bytes 1 2 1 2))))
 
 (test-case
- "buffer: should encode length before buffer"
- (check-equal? (encode (x:buffer #:length uint8) (bytes #xab #xff) #f) (bytes 2 #xab #xff)))
\ No newline at end of file
+ "bytes: should encode length before bytes"
+ (check-equal? (encode (x:bytes #:length uint8) (bytes #xab #xff) #f) (bytes 2 #xab #xff)))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/test/list-test.rkt b/xenomorph/xenomorph/test/list-test.rkt
new file mode 100644
index 00000000..cc9ebb5f
--- /dev/null
+++ b/xenomorph/xenomorph/test/list-test.rkt
@@ -0,0 +1,116 @@
+#lang racket/base
+(require rackunit
+         racket/class
+         "../list.rkt"
+         "../struct.rkt"
+         "../number.rkt"
+         "../pointer.rkt"
+         "../base.rkt"
+         sugar/unstable/dict)
+
+#|
+approximates
+https://github.com/mbutterick/restructure/blob/master/test/Array.coffee
+|#
+
+(test-case 
+ "list: decode fixed length"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8 #:length 4)) '(1 2 3 4))))
+
+(test-case 
+ "list: decode nested"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type (x:struct 'foo uint8) #:length 4))
+                 (list (mhasheq 'foo 1)
+                       (mhasheq 'foo 2)
+                       (mhasheq 'foo 3)
+                       (mhasheq 'foo 4)))))
+
+(test-case 
+ "list: decode with post-decode"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (define xa (x:list #:type uint8 #:length 4 #:post-decode (λ (val) (map (λ (x) (* 2 x)) val))))
+   (check-equal? (decode xa) '(2 4 6 8))))
+
+(test-case 
+ "list: decode fixed number of bytes"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint16be #:length 4 #:count-bytes #t)) '(258 772))))
+
+(test-case 
+ "list: decode length from parent key"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8 #:length 'len) (current-input-port) #:parent (mhash 'len 4)) '(1 2 3 4))))
+
+(test-case 
+ "list: decode byte count from parent key"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint16be #:length 'len #:count-bytes #t) (current-input-port) #:parent (mhash 'len 4)) '(258 772))))
+
+(test-case 
+ "list: decode length as number before array"
+ (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8 #:length uint8)) '(1 2 3 4))))
+
+(test-case 
+ "list: decode byte count as number before array"
+ (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint16be #:length uint8 #:count-bytes #t)) '(258 772))))
+
+(test-case 
+ "list: decode length from function"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8 #:length (λ _ 4))) '(1 2 3 4))))
+
+(test-case 
+ "list: decode byte count from function"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint16be #:length (λ _ 4) #:count-bytes #t)) '(258 772))))
+
+(test-case 
+ "list: decode to the end of parent if no length given"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8) (current-input-port) #:parent (mhash x:length-key 4 x:start-offset-key 0)) '(1 2 3 4))))
+
+(test-case 
+ "list: decode to the end of the stream if parent exists, but its length is 0"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:list #:type uint8) (current-input-port) #:parent (mhash x:length-key 0 x:start-offset-key 0)) '(1 2 3 4 5))))
+
+(test-case 
+ "list: decode to the end of the stream if no parent and length is given"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4))])
+   (check-equal? (decode (x:list #:type uint8)) '(1 2 3 4 ))))
+
+(test-case 
+ "list: use array length"
+ (check-equal? (size (x:list #:type uint8 #:length 10) '(1 2 3 4)) 4))
+
+(test-case 
+ "list: add size of length field before string"
+ (check-equal? (size (x:list #:type uint8 #:length uint8) '(1 2 3 4)) 5))
+
+(test-case 
+ "list: use defined length if no value given"
+ (check-equal? (size (x:list #:type uint8 #:length 10)) 10))
+
+(test-case 
+ "list: encode using array length"
+ (check-equal? (encode (x:list #:type uint8 #:length 10) '(1 2 3 4) #f) (bytes 1 2 3 4)))
+
+(test-case 
+ "list: encode with pre-encode"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (define xa (x:list #:type uint8 #:length 4 #:pre-encode (λ (val) (map (λ (x) (* 2 x)) val))))
+   (check-equal? (encode xa '(1 2 3 4) #f) (bytes 2 4 6 8))))
+
+(test-case 
+ "list: encode length as number before array"
+ (check-equal? (encode (x:list #:type uint8 #:length uint8) '(1 2 3 4) #f) (bytes 4 1 2 3 4)))
+
+(test-case 
+   "list: add pointers after array if length is encoded at start"
+   (check-equal? (encode (x:list #:type (x:pointer #:offset-type uint8
+                                             #:type uint8)
+                                  #:length uint8) '(1 2 3 4) #f) (bytes 4 5 6 7 8 1 2 3 4)))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/test/main.rkt b/xenomorph/xenomorph/test/main.rkt
index 87f862af..86fafe9a 100644
--- a/xenomorph/xenomorph/test/main.rkt
+++ b/xenomorph/xenomorph/test/main.rkt
@@ -1,14 +1,16 @@
 #lang racket/base
 
-(require "array-test.rkt"
-         "bitfield-test.rkt"
-         "buffer-test.rkt"
+(require "bitfield-test.rkt"
+         "bytes-test.rkt"
          "enum-test.rkt"
-         "lazy-array-test.rkt"
+         "list-test.rkt"
          "number-test.rkt"
          "optional-test.rkt"
          "pointer-test.rkt"
          "reserved-test.rkt"
+         "stream-test.rkt"
          "string-test.rkt"
+         "symbol-test.rkt"
          "struct-test.rkt"
+         "vector-test.rkt"
          "versioned-struct-test.rkt")
diff --git a/xenomorph/xenomorph/test/lazy-array-test.rkt b/xenomorph/xenomorph/test/stream-test.rkt
similarity index 82%
rename from xenomorph/xenomorph/test/lazy-array-test.rkt
rename to xenomorph/xenomorph/test/stream-test.rkt
index f5c8ecb6..86e43bfd 100644
--- a/xenomorph/xenomorph/test/lazy-array-test.rkt
+++ b/xenomorph/xenomorph/test/stream-test.rkt
@@ -2,10 +2,10 @@
 (require rackunit
          racket/class
          racket/stream
-         "../array.rkt"
+         "../list.rkt"
          "../base.rkt"
          "../number.rkt"
-         "../lazy-array.rkt"
+         "../stream.rkt"
          "../base.rkt")
 
 #|
@@ -16,7 +16,7 @@ https://github.com/mbutterick/restructure/blob/master/test/LazyArray.coffee
 (test-case
  "lazy-array: decode should decode items lazily"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4))
+   (define xla (x:stream uint8 4))
    (define arr (decode xla))
    (check-equal? (stream-length arr) 4)
    (check-equal? (pos (current-input-port)) 4)
@@ -28,9 +28,9 @@ https://github.com/mbutterick/restructure/blob/master/test/LazyArray.coffee
 (test-case
  "lazy-array: decode should decode items lazily with post-decode"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4 #:post-decode (λ (str) (stream-map (λ (i) (* 2 i)) str))))
+   (define xla (x:stream uint8 4 #:post-decode (λ (str) (stream-map (λ (i) (* 2 i)) str))))
    (define arr (decode xla))
-   (check-false (x:array? arr))
+   (check-false (x:list? arr))
    (check-equal? (stream-length arr) 4)
    (check-equal? (pos (current-input-port)) 4)
    (check-equal? (stream-ref arr 0) 2)
@@ -41,34 +41,34 @@ https://github.com/mbutterick/restructure/blob/master/test/LazyArray.coffee
 (test-case
  "lazy-array: should be able to convert to an array"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4))
+   (define xla (x:stream uint8 4))
    (define arr (decode xla))
    (check-equal? (stream->list arr) '(1 2 3 4))))
 
 (test-case
  "lazy-array: decode should decode length as number before array"
  (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 uint8))
+   (define xla (x:stream uint8 uint8))
    (define arr (decode xla))
    (check-equal? (stream->list arr) '(1 2 3 4))))
 
 (test-case
  "lazy-array: size should work with xlazy-arrays"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4))
+   (define xla (x:stream uint8 4))
    (define arr (decode xla))
    (check-equal? (size xla arr) 4)))
 
 (test-case
  "lazy-array: encode should work with xlazy-arrays"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4))
+   (define xla (x:stream uint8 4))
    (define arr (decode xla))  
    (check-equal? (encode xla arr #f) (bytes 1 2 3 4))))
 
 (test-case
  "lazy-array: encode should work with xlazy-arrays with pre-encode"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
-   (define xla (x:lazy-array uint8 4 #:pre-encode (λ (str) (stream-map (λ (val) (* 2 val)) str))))
+   (define xla (x:stream uint8 4 #:pre-encode (λ (str) (stream-map (λ (val) (* 2 val)) str))))
    (define arr (decode xla))  
    (check-equal? (encode xla arr #f) (bytes 2 4 6 8))))
diff --git a/xenomorph/xenomorph/test/symbol-test.rkt b/xenomorph/xenomorph/test/symbol-test.rkt
new file mode 100644
index 00000000..fcc55823
--- /dev/null
+++ b/xenomorph/xenomorph/test/symbol-test.rkt
@@ -0,0 +1,120 @@
+#lang racket/base
+(require rackunit
+         racket/class
+         "../base.rkt"
+         "../symbol.rkt"
+         "../number.rkt"
+         "../base.rkt"
+         sugar/unstable/dict)
+
+
+(test-case
+ "symbol: decode fixed length"
+ (parameterize ([current-input-port (open-input-bytes #"testing")])
+   (check-equal? (decode (x:symbol 7)) 'testing)))
+
+(test-case
+ "symbol: decode fixed length with post-decode"
+ (parameterize ([current-input-port (open-input-bytes #"testing")])
+   (define xs (x:symbol 7 #:post-decode (λ (val) '|ring a ding|)))
+   (check-equal? (decode xs) '|ring a ding|)))
+
+(test-case
+ "symbol: decode length from parent key"
+ (parameterize ([current-input-port (open-input-bytes #"testing")])
+   (check-equal? (decode (x:symbol 'len) (current-input-port) #:parent (mhash 'len 7)) 'testing)))
+
+(test-case
+ "symbol: decode length as number before symbol"
+ (parameterize ([current-input-port (open-input-bytes #"\x07testing")])
+   (check-equal? (decode (x:symbol uint8) (current-input-port) #:parent (mhash 'len 7)) 'testing)))
+
+(test-case
+ "symbol: decode utf8"
+ (parameterize ([current-input-port (open-input-bytes (string->bytes/utf-8 "🍻"))])
+   (check-equal? (decode (x:symbol 4 'utf8)) '🍻)))
+
+(test-case
+ "symbol: decode encoding computed from function"
+ (parameterize ([current-input-port (open-input-bytes (string->bytes/utf-8 "🍻"))])
+   (check-equal? (decode (x:symbol 4 (λ _ 'utf8))) '🍻)))
+
+(test-case
+ "symbol: decode null-terminated symbol and read past terminator"
+ (parameterize ([current-input-port (open-input-bytes (string->bytes/utf-8 "🍻\x00"))])
+   (check-equal? (decode (x:symbol #f 'utf8)) '🍻)
+   (check-equal? (pos (current-input-port)) 5)))
+
+(test-case
+ "symbol: decode remainder of buffer when null-byte missing"
+ (parameterize ([current-input-port (open-input-bytes (string->bytes/utf-8 "🍻"))])
+   (check-equal? (decode (x:symbol #f 'utf8)) '🍻)))
+
+(test-case
+ "symbol: size should use symbol length"
+ (check-equal? (size (x:symbol 7) 'testing) 7))
+
+(test-case
+ "symbol: size should use correct encoding"
+ (check-equal? (size (x:symbol 10 'utf8) '🍻) 4))
+
+(test-case
+ "symbol: size should use encoding from function"
+ (check-equal? (size (x:symbol 10 (λ _ 'utf8)) '🍻) 4))
+
+(test-case
+ "symbol: should add size of length field before symbol"
+ (check-equal? (size (x:symbol uint8 'utf8) '🍻) 5))
+
+; todo: it "should work with utf16be encoding"
+
+(test-case
+ "symbol: size should take null-byte into account"
+ (check-equal? (size (x:symbol #f 'utf8) '🍻) 5))
+
+(test-case
+ "symbol: size should use defined length if no value given"
+ (check-equal? (size (x:symbol 10)) 10))
+
+(test-case
+ "symbol: encode using symbol length"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol 7) 'testing)
+   (check-equal? (get-output-bytes (current-output-port)) #"testing")))
+
+(test-case
+ "symbol: encode using symbol length and pre-encode"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (define xs (x:symbol 7 #:pre-encode (λ (val) (string->symbol (list->string (reverse (string->list (symbol->string val))))))))
+   (encode xs 'testing)
+   (check-equal? (get-output-bytes (current-output-port)) #"gnitset")))
+
+(test-case
+ "symbol: encode length as number before symbol"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol uint8) 'testing)
+   (check-equal? (get-output-bytes (current-output-port)) #"\x07testing")))
+
+(test-case
+ "symbol: encode length as number before symbol utf8"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol uint8 'utf8) "testing 😜")
+   (check-equal? (get-output-bytes (current-output-port)) (string->bytes/utf-8 "\x0ctesting 😜"))))
+
+(test-case
+ "symbol: encode utf8"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol 4 'utf8) '🍻 )
+   (check-equal? (get-output-bytes (current-output-port)) (string->bytes/utf-8 "🍻"))))
+
+(test-case
+ "symbol: encode encoding computed from function"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol 4 (λ _ 'utf8)) '🍻)
+   (check-equal? (get-output-bytes (current-output-port)) (string->bytes/utf-8 "🍻"))))
+
+(test-case
+ "symbol: encode null-terminated symbol"
+ (parameterize ([current-output-port (open-output-bytes)])
+   (encode (x:symbol #f 'utf8) '🍻  )
+   (check-equal? (get-output-bytes (current-output-port)) (string->bytes/utf-8 "🍻\x00"))))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/test/vector-test.rkt b/xenomorph/xenomorph/test/vector-test.rkt
new file mode 100644
index 00000000..7dea2021
--- /dev/null
+++ b/xenomorph/xenomorph/test/vector-test.rkt
@@ -0,0 +1,117 @@
+#lang racket/base
+(require rackunit
+         racket/class
+         racket/vector
+         "../vector.rkt"
+         "../struct.rkt"
+         "../number.rkt"
+         "../pointer.rkt"
+         "../base.rkt"
+         sugar/unstable/dict)
+
+#|
+approximates
+https://github.com/mbutterick/restructure/blob/master/test/Array.coffee
+|#
+
+(test-case 
+ "vector: decode fixed length"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8 #:length 4)) '#(1 2 3 4))))
+
+(test-case 
+ "vector: decode nested"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type (x:struct 'foo uint8) #:length 4))
+                 (vector (mhasheq 'foo 1)
+                       (mhasheq 'foo 2)
+                       (mhasheq 'foo 3)
+                       (mhasheq 'foo 4)))))
+
+(test-case 
+ "vector: decode with post-decode"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (define xa (x:vector #:type uint8 #:length 4 #:post-decode (λ (val) (vector-map (λ (x) (* 2 x)) val))))
+   (check-equal? (decode xa) '#(2 4 6 8))))
+
+(test-case 
+ "vector: decode fixed number of bytes"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint16be #:length 4 #:count-bytes #t)) '#(258 772))))
+
+(test-case 
+ "vector: decode length from parent key"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8 #:length 'len) (current-input-port) #:parent (mhash 'len 4)) '#(1 2 3 4))))
+
+(test-case 
+ "vector: decode byte count from parent key"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint16be #:length 'len #:count-bytes #t) (current-input-port) #:parent (mhash 'len 4)) '#(258 772))))
+
+(test-case 
+ "vector: decode length as number before array"
+ (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8 #:length uint8)) '#(1 2 3 4))))
+
+(test-case 
+ "vector: decode byte count as number before array"
+ (parameterize ([current-input-port (open-input-bytes (bytes 4 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint16be #:length uint8 #:count-bytes #t)) '#(258 772))))
+
+(test-case 
+ "vector: decode length from function"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8 #:length (λ _ 4))) '#(1 2 3 4))))
+
+(test-case 
+ "vector: decode byte count from function"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint16be #:length (λ _ 4) #:count-bytes #t)) '#(258 772))))
+
+(test-case 
+ "vector: decode to the end of parent if no length given"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8) (current-input-port) #:parent (mhash x:length-key 4 x:start-offset-key 0)) '#(1 2 3 4))))
+
+(test-case 
+ "vector: decode to the end of the stream if parent exists, but its length is 0"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (check-equal? (decode (x:vector #:type uint8) (current-input-port) #:parent (mhash x:length-key 0 x:start-offset-key 0)) '#(1 2 3 4 5))))
+
+(test-case 
+ "vector: decode to the end of the stream if no parent and length is given"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4))])
+   (check-equal? (decode (x:vector #:type uint8)) '#(1 2 3 4 ))))
+
+(test-case 
+ "vector: use array length"
+ (check-equal? (size (x:vector #:type uint8 #:length 10) '#(1 2 3 4)) 4))
+
+(test-case 
+ "vector: add size of length field before string"
+ (check-equal? (size (x:vector #:type uint8 #:length uint8) '#(1 2 3 4)) 5))
+
+(test-case 
+ "vector: use defined length if no value given"
+ (check-equal? (size (x:vector #:type uint8 #:length 10)) 10))
+
+(test-case 
+ "vector: encode using array length"
+ (check-equal? (encode (x:vector #:type uint8 #:length 10) '#(1 2 3 4) #f) (bytes 1 2 3 4)))
+
+(test-case 
+ "vector: encode with pre-encode"
+ (parameterize ([current-input-port (open-input-bytes (bytes 1 2 3 4 5))])
+   (define xa (x:vector #:type uint8 #:length 4 #:pre-encode (λ (val) (vector-map (λ (x) (* 2 x)) val))))
+   (check-equal? (encode xa '#(1 2 3 4) #f) (bytes 2 4 6 8))))
+
+(test-case 
+ "vector: encode length as number before array"
+ (check-equal? (encode (x:vector #:type uint8 #:length uint8) '#(1 2 3 4) #f) (bytes 4 1 2 3 4)))
+
+(test-case 
+   "vector: add pointers after array if length is encoded at start"
+   (check-equal? (encode (x:vector #:type (x:pointer #:offset-type uint8
+                                             #:type uint8)
+                                  #:length uint8) '#(1 2 3 4) #f) (bytes 4 5 6 7 8 1 2 3 4)))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/vector.rkt b/xenomorph/xenomorph/vector.rkt
new file mode 100644
index 00000000..9367790e
--- /dev/null
+++ b/xenomorph/xenomorph/vector.rkt
@@ -0,0 +1,40 @@
+#lang debug racket/base
+(require racket/class
+         "base.rkt"
+         "number.rkt"
+         "util.rkt"
+         "list.rkt"
+         sugar/unstable/dict)
+(provide (all-defined-out))
+
+(define x:vector%
+  (class x:list%
+    (super-new)
+
+    (define/override (pre-encode val)
+      (unless (or (vector? val) (list? val))
+        (raise-argument-error 'x:vector-encode "vector or list" val))
+      (if (vector? val) (vector->list val) val))
+    
+    (define/override (post-decode val) (list->vector val))))
+
+(define (x:vector [type-arg #f] [len-arg #f] [length-type-arg 'count]
+                 #:type [type-kwarg #f]
+                 #:length [len-kwarg #f]
+                 #:count-bytes [count-bytes? #f]
+                 #:pre-encode [pre-proc #f]
+                 #:post-decode [post-proc #f]
+                 #:base-class [base-class x:vector%])
+  (new (generate-subclass base-class pre-proc post-proc) [type (or type-arg type-kwarg)]
+       [len (or len-arg len-kwarg)]
+       [count-bytes? count-bytes?]))
+
+(define (x:vector? x) (is-a? x x:vector%))
+
+(module+ test
+  (require rackunit)
+  (check-equal? (decode (x:vector uint16be 3) #"ABCDEF") '#(16706 17220 17734))
+  (check-equal? (encode (x:vector uint16be 3) '(16706 17220 17734) #f) #"ABCDEF")
+  (check-equal? (encode (x:vector uint16be 3) '#(16706 17220 17734) #f) #"ABCDEF")
+  (check-equal? (size (x:vector uint16be) '#(1 2 3)) 6)
+  (check-equal? (size (x:vector doublebe) '#(1 2 3 4 5)) 40))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/versioned-struct.rkt b/xenomorph/xenomorph/versioned-struct.rkt
index eada5210..94fd61b2 100644
--- a/xenomorph/xenomorph/versioned-struct.rkt
+++ b/xenomorph/xenomorph/versioned-struct.rkt
@@ -17,7 +17,7 @@ https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
     (init-field [(@type type)] [(@versions versions)])
 
     (unless (for/or ([proc (list integer? procedure? xenomorphic-type? symbol?)])
-              (proc @type))
+                    (proc @type))
       (raise-argument-error 'x:versioned-struct "integer, procedure, symbol, or xenomorphic" @type))
     (unless (and (dict? @versions) (andmap (λ (v) (or (dict? v) (x:struct? v))) (dict-values @versions)))
       (raise-argument-error 'x:versioned-struct "dict of dicts or structish" @versions))
@@ -42,19 +42,15 @@ https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
                               [_ (send @type x:decode port parent)]))
       (dict-set! res x:version-key which-version)
 
-      (cond
-        [(dict-ref @versions 'header #f)
-         => (λ (header-val) (parse-fields port res header-val))])
+      (match (dict-ref @versions 'header #f)
+        [#false (void)]
+        [header-val (parse-fields port res header-val)])
       
-      (define field-object
-        (cond
-          [(dict-ref @versions which-version #f) => values]
-          [else
-           (raise-argument-error 'x:versioned-struct-decode (format "valid field version: ~v" (dict-keys @versions)) which-version)]))
-      
-      (match field-object
-        [(? x:versioned-struct?) (send field-object x:decode port parent)]
-        [_ (parse-fields port res field-object)]))
+      (match (dict-ref @versions which-version #f)
+        [#false (raise-argument-error 'x:versioned-struct-decode
+                                      (format "valid field version: ~v" (dict-keys @versions)) which-version)]
+        [(? x:versioned-struct? vs) (send vs x:decode port parent)]
+        [field-object (parse-fields port res field-object)]))
 
     (define/override (pre-encode val) val)
 
@@ -70,13 +66,13 @@ https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
       (unless (or (symbol? @type) (procedure? @type))
         (send @type x:encode (dict-ref field-data x:version-key #f) port parent))
       (for ([(key type) (in-dict (dict-ref @versions 'header null))])
-        (send type x:encode (dict-ref field-data key) port parent))
+           (send type x:encode (dict-ref field-data key) port parent))
 
       (define fields (select-field-set field-data))
       (unless (andmap (λ (key) (member key (dict-keys field-data))) (dict-keys fields))
         (raise-argument-error 'x:versioned-struct-encode (format "hash that contains superset of xversioned-struct keys: ~a" (dict-keys fields)) (dict-keys field-data)))
       (for ([(key type) (in-dict fields)])
-        (send type x:encode (dict-ref field-data key) port parent))
+           (send type x:encode (dict-ref field-data key) port parent))
       (let loop ([i 0])
         (when (< i (length (dict-ref parent x:pointers-key)))
           (define ptr (list-ref (dict-ref parent x:pointers-key) i))
@@ -98,10 +94,10 @@ https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
       
       (define header-size
         (for/sum ([(key type) (in-dict (dict-ref @versions 'header null))])
-          (send type x:size (and val (dict-ref val key)) parent)))
+                 (send type x:size (and val (dict-ref val key)) parent)))
       (define fields-size
         (for/sum ([(key type) (in-dict (select-field-set val))])
-          (send type x:size (and val (dict-ref val key)) parent)))
+                 (send type x:size (and val (dict-ref val key)) parent)))
       (define pointer-size (if include-pointers (dict-ref parent x:pointer-size-key) 0))
       (+ version-size header-size fields-size pointer-size))))