Add sort and cannonicalize

preserves.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version = "20230607"
+version = "20230611"
 author        = "Emery Hemingway"
 description   = "data model and serialization format"
 license       = "Unlicense"

src/preserves.nim

@@ -4,6 +4,7 @@
 import std/[base64, endians, hashes, options, sets, sequtils, streams, tables, typetraits]
 import ./preserves/private/macros
 
+from std/algorithm import sort
 from std/json import escapeJson, escapeJsonUnquoted
 from std/strutils import parseEnum
 import ./preserves/private/dot
@@ -167,6 +168,30 @@ proc `<`*[A, B](x: Preserve[A]; y: Preserve[B]): bool =
       when (not A is void) and (A is B):
         result = x.embed < y.embed
 
+proc cmp*[E](x, y: var Preserve[E]): int =
+  if x == y: 0
+  elif x < y: -1
+  else: 1
+
+proc sort*[E](pr: var Preserve[E]) = sort(pr.sequence, cmp)
+  ## Sort a Preserves array by total ordering.
+
+proc cannonicalize*[E](pr: var Preserve[E]) {.gcsafe.} =
+  ## Cannonicalize a compound Preserves value by total ordering.
+  case pr.kind
+  of pkSequence:
+    apply(pr.sequence, cannonicalize)
+  of pkSet:
+    apply(pr.set, cannonicalize)
+    sort(pr.set)
+  of pkDictionary:
+    apply(pr.dict) do (e: var DictEntry[E]):
+      cannonicalize(e.val)
+    sort(pr.dict) do (x, y: DictEntry[E]) -> int:
+      cmp(x.key, y.key)
+  else:
+    discard
+
 proc hash*(pr: Preserve): Hash =
   ## Produce a `Hash` of `pr` for use with a `HashSet` or `Table`.
   var h = hash(pr.kind.int) !& hash(pr.embedded)