Hash nil embedded pointers

preserves.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version = "20231028"
+version = "20231102"
 author        = "Emery Hemingway"
 description   = "data model and serialization format"
 license       = "Unlicense"

src/preserves.nim

@@ -223,7 +223,7 @@ proc cannonicalize*[E](pr: var Preserve[E]) =
   else:
     discard
 
-proc hash*(pr: Preserve): Hash =
+proc hash*[E](pr: Preserve[E]): Hash =
   ## Produce a `Hash` of `pr` for use with a `HashSet` or `Table`.
   var h = hash(pr.kind.int) !& hash(pr.embedded)
   case pr.kind
@@ -254,7 +254,13 @@ proc hash*(pr: Preserve): Hash =
     for (key, val) in pr.dict.items:
       h = h !& hash(key) !& hash(val)
   of pkEmbedded:
+    when E is void:
       h = h !& hash(pr.embed)
+    else:
+      if pr.embed.isNil:
+        h = h !& hash(false)
+      else:
+        h = h !& hash(pr.embed)
   !$h
 
 proc `[]`*(pr: Preserve; i: int): Preserve =
@@ -284,6 +290,18 @@ proc getOrDefault(pr: Preserve; key: Preserve): Preserve =
         result = v
         break
 
+proc pop*(pr: var Preserve; key: Preserve; val: var Preserve): bool =
+  ##  Deletes the `key` from a Preserves dictionary.
+  ## Returns true, if the key existed, and sets `val` to the mapping
+  ## of the key. Otherwise, returns false, and the `val` is unchanged.
+  if pr.kind == pkDictionary:
+    var i = 0
+    while i < pr.dict.len:
+      if pr.dict[i].key == key:
+        val = move pr.dict[i].val
+        delete(pr.dict, i, i)
+        return true
+
 proc incl*(pr: var Preserve; key: Preserve) =
   ## Include `key` in the Preserves set `pr`.
   for i in 0..pr.set.high:
@@ -638,7 +656,6 @@ proc encode*[E](pr: Preserve[E]): seq[byte] =
   s.write pr
   result = cast[seq[byte]](move s.data)
 
-
 proc decodePreserves*(s: Stream; E = void): Preserve[E] =
   ## Decode a Preserves value from a binary-encoded stream.
   if s.atEnd: raise newException(IOError, "End of Preserves stream")