diff --git a/preserves.nimble b/preserves.nimble
index 56b87c2..afbe389 100644
--- a/preserves.nimble
+++ b/preserves.nimble
@@ -1,6 +1,6 @@
 # Package
 
-version = "20230403"
+version = "20230410"
 author        = "Emery Hemingway"
 description   = "data model and serialization format"
 license       = "Unlicense"
diff --git a/src/preserves/Tupfile b/src/preserves/Tupfile
index d6bea78..aee9354 100644
--- a/src/preserves/Tupfile
+++ b/src/preserves/Tupfile
@@ -1,2 +1,3 @@
 include_rules
 : foreach preserves_schema_nim.nim schemac.nim |> !nim |> $(BIN_DIR)/%B | $(BIN_DIR)/<%B>
+: foreach *hooks.nim |> !nim_check |>
diff --git a/src/preserves/jsonhooks.nim b/src/preserves/jsonhooks.nim
index 6d97730..45c0c96 100644
--- a/src/preserves/jsonhooks.nim
+++ b/src/preserves/jsonhooks.nim
@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2021 ☭ Emery Hemingway
+# SPDX-FileCopyrightText: ☭ Emery Hemingway
 # SPDX-License-Identifier: Unlicense
 
 import std/[json, tables]
@@ -28,7 +28,14 @@ proc toPreserveHook*(js: JsonNode; E: typedesc): Preserve[E] =
     for i, e in js.elems:
       result.sequence[i] = toPreserveHook(e, E)
 
-proc fromPreserveHook*[E](js: var JsonNode; prs: Preserve[E]): bool =
+proc fromPreserveHook*[E](js: var JsonNode; prs: Preserve[E]): bool {.gcsafe.} =
+  runnableExamples:
+    import std/json
+    var js = JsonNode()
+    var pr = js.toPreserveHook(void)
+    assert fromPreserveHook(js, pr)
+    fromJsonHook(pr, js)
+    js = toJsonHook(pr)
   case prs.kind:
   of pkBoolean:
     js = newJBool(prs.bool)
@@ -54,14 +61,14 @@ proc fromPreserveHook*[E](js: var JsonNode; prs: Preserve[E]): bool =
     js = newJArray()
     js.elems.setLen(prs.sequence.len)
     for i, val in prs.sequence:
-      if not fromPreserve(js.elems[i], val):
+      if not fromPreserveHook(js.elems[i], val):
         return false
   of pkSet:
     js = newJArray()
     js.elems.setLen(prs.set.len)
     var i: int
     for val in prs.set:
-      if not fromPreserve(js.elems[i], val):
+      if not fromPreserveHook(js.elems[i], val):
         return false
       inc i
   of pkDictionary:
@@ -70,7 +77,7 @@ proc fromPreserveHook*[E](js: var JsonNode; prs: Preserve[E]): bool =
       if key.kind != pkString:
         return false
       var jsVal: JsonNode
-      if not fromPreserve(jsVal, val): return false
+      if not fromPreserveHook(jsVal, val): return false
       js[key.string] = jsVal
   else: return false
   true
@@ -81,10 +88,3 @@ proc toJsonHook*[E](pr: Preserve[E]): JsonNode =
 
 proc fromJsonHook*[E](pr: var Preserve[E]; js: JsonNode) =
   pr = toPreserveHook(js, E)
-
-when isMainModule:
-  var js = JsonNode()
-  var pr = js.toPreserveHook(void)
-  assert fromPreserveHook(js, pr)
-  fromJsonHook(pr, js)
-  js = toJsonHook(pr)