From 10fc78172e2dff76fd431c32f520142fd7b11bf1 Mon Sep 17 00:00:00 2001
From: Emery Hemingway <ehmry@posteo.net>
Date: Thu, 28 Dec 2023 18:18:06 +0200
Subject: [PATCH] Add `&` operator

---
 src/preserves.nim | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/preserves.nim b/src/preserves.nim
index 8d9940e..2c27d25 100644
--- a/src/preserves.nim
+++ b/src/preserves.nim
@@ -123,6 +123,25 @@ func isEmbedded*(pr: Value): bool {.inline.} =
   ## Check if ``pr`` is an embedded value.
   pr.embedded or pr.kind == pkEmbedded
 
+proc `&`*(x, y: Value): Value =
+  ## Concatenate operator.
+  if x.kind != y.kind:
+    raise newException(ValueError, "cannot concatenate heterogenous values")
+  case x.kind
+  of pkString:
+    result = Value(kind: pkString, string: x.string & y.string)
+  of pkByteString:
+    result = Value(kind: pkByteString, bytes: x.bytes & y.bytes)
+  of pkSequence:
+    result = Value(kind: pkSequence, sequence: x.sequence & y.sequence)
+  else:
+    raise newException(ValueError, "cannot concatenate this value type")
+
+proc `&`*(x: Value; y: seq[Value]): Value =
+  if x.kind != pkSequence:
+    raise newException(ValueError, "cannot concatenate to non-sequence value")
+  result = Value(kind: pkSequence, sequence: x.sequence & y)
+
 proc getOrDefault(pr, key: Value): Value =
   ## Retrieves the value of `pr[key]` if `pr` is a dictionary containing `key`
   ## or returns the `#f` Preserves value.