From cb858bc636570918eafc083e7b196ab94f6f0b74 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Thu, 13 Dec 2018 11:46:03 -0800
Subject: [PATCH] replace lazy-thunk with delay / force

---
 xenomorph/xenomorph/redo/helper.rkt            | 4 +---
 xenomorph/xenomorph/redo/pointer.rkt           | 3 ++-
 xenomorph/xenomorph/redo/struct.rkt            | 9 +++++++--
 xenomorph/xenomorph/redo/test/pointer-test.rkt | 3 ++-
 xenomorph/xenomorph/redo/versioned-struct.rkt  | 1 +
 5 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/xenomorph/xenomorph/redo/helper.rkt b/xenomorph/xenomorph/redo/helper.rkt
index b972a62b..12d0026a 100644
--- a/xenomorph/xenomorph/redo/helper.rkt
+++ b/xenomorph/xenomorph/redo/helper.rkt
@@ -56,6 +56,4 @@
   (cond
     [(void? size) 0]
     [(and (integer? size) (not (negative? size))) size]
-    [else (raise-argument-error 'size "nonnegative integer" size)]))
-
-(struct lazy-thunk (proc) #:transparent)
\ No newline at end of file
+    [else (raise-argument-error 'size "nonnegative integer" size)]))
\ No newline at end of file
diff --git a/xenomorph/xenomorph/redo/pointer.rkt b/xenomorph/xenomorph/redo/pointer.rkt
index 4e317d30..83d96131 100644
--- a/xenomorph/xenomorph/redo/pointer.rkt
+++ b/xenomorph/xenomorph/redo/pointer.rkt
@@ -1,6 +1,7 @@
 #lang debug racket/base
 (require "helper.rkt"
          racket/dict
+         racket/promise
          sugar/unstable/dict)
 (provide (all-defined-out))
 
@@ -42,7 +43,7 @@ https://github.com/mbutterick/restructure/blob/master/src/Pointer.coffee
              (pos port orig-pos)
              val]))
         (if (pointer-lazy? xp)
-            (lazy-thunk decode-value)
+            (delay (decode-value))
             (decode-value))]
        [else ptr])])))
 
diff --git a/xenomorph/xenomorph/redo/struct.rkt b/xenomorph/xenomorph/redo/struct.rkt
index 48cd122a..b29dfa97 100644
--- a/xenomorph/xenomorph/redo/struct.rkt
+++ b/xenomorph/xenomorph/redo/struct.rkt
@@ -1,5 +1,10 @@
 #lang debug racket/base
-(require (prefix-in d: racket/dict) racket/list "helper.rkt" "number.rkt" sugar/unstable/dict)
+(require (prefix-in d: racket/dict)
+         racket/promise
+         racket/list
+         "helper.rkt"
+         "number.rkt"
+         sugar/unstable/dict)
 (provide (all-defined-out))
 
 #|
@@ -19,7 +24,7 @@ https://github.com/mbutterick/restructure/blob/master/src/Struct.coffee
   [(define (dict-set! d k v) (d:dict-set! (choose-dict d k) k v))
    (define (dict-ref d k [thunk #f])
      (define res (d:dict-ref (choose-dict d k) k thunk))
-     (if (lazy-thunk? res) ((lazy-thunk-proc res)) res))
+     (force res))
    (define (dict-remove! d k) (d:dict-remove! (choose-dict d k) k))
    ;; public keys only
    (define (dict-keys d) (d:dict-keys (struct-dict-res-_kv d)))
diff --git a/xenomorph/xenomorph/redo/test/pointer-test.rkt b/xenomorph/xenomorph/redo/test/pointer-test.rkt
index a677c23b..b828cedd 100644
--- a/xenomorph/xenomorph/redo/test/pointer-test.rkt
+++ b/xenomorph/xenomorph/redo/test/pointer-test.rkt
@@ -5,6 +5,7 @@
          "../pointer.rkt"
          "../number.rkt"
          "../struct.rkt"
+         racket/promise
          sugar/unstable/dict)
 
 #|
@@ -59,7 +60,7 @@ https://github.com/mbutterick/restructure/blob/master/test/Pointer.coffee
  "decode should support decoding pointers lazily"
  (parameterize ([current-input-port (open-input-bytes (bytes 1 53))])
    (define res (decode (+xstruct (dictify 'ptr (+xpointer uint8 uint8 (mhasheq 'lazy #t))))))
-   (check-true (lazy-thunk? (dict-ref (struct-dict-res-_kv res) 'ptr)))
+   (check-true (promise? (dict-ref (struct-dict-res-_kv res) 'ptr)))
    (check-equal? (dict-ref res 'ptr) 53)))
 
 (test-case
diff --git a/xenomorph/xenomorph/redo/versioned-struct.rkt b/xenomorph/xenomorph/redo/versioned-struct.rkt
index 1c4fdbd2..b3ef3c81 100644
--- a/xenomorph/xenomorph/redo/versioned-struct.rkt
+++ b/xenomorph/xenomorph/redo/versioned-struct.rkt
@@ -15,6 +15,7 @@ https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
 
   (dict-set! res 'version
              (cond
+               [(integer? (xversioned-struct-type xvs)) (xversioned-struct-type xvs)]
                #;[forced-version] ; for testing purposes: pass an explicit version
                [(or (symbol? (xversioned-struct-type xvs)) (procedure? (xversioned-struct-type xvs)))
                 (unless parent