From c8c8e3b7e27cd0d14d00a72bc8f6af0aaad58cf0 Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Sun, 11 Nov 2018 13:40:19 +0200
Subject: [PATCH] Initial simple/naive implementation of the field enumeration
 logic

---
 serialization.nim                      |  7 +++-
 serialization.nimble                   | 13 +------
 serialization/object_serialization.nim | 52 ++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 14 deletions(-)
 create mode 100644 serialization/object_serialization.nim

diff --git a/serialization.nim b/serialization.nim
index 23bef05..fdcd59f 100644
--- a/serialization.nim
+++ b/serialization.nim
@@ -1,5 +1,8 @@
-import streams
-export streams
+import
+  serialization/[streams, object_serialization]
+
+export
+  streams, object_serialization
 
 proc encode*(Writer: type, value: auto): auto =
   # TODO: define a concept for the Writer types
diff --git a/serialization.nimble b/serialization.nimble
index 82c032b..58be127 100644
--- a/serialization.nimble
+++ b/serialization.nimble
@@ -3,19 +3,8 @@ mode = ScriptMode.Verbose
 packageName   = "serialization"
 version       = "0.1.0"
 author        = "Status Research & Development GmbH"
-description   = "A modern extensible serialization framework for Nim"
+description   = "A modern and extensible serialization framework for Nim"
 license       = "Apache License 2.0"
 skipDirs      = @["tests"]
 
 requires "nim >= 0.19.0"
-
-proc configForTests() =
-  --hints: off
-  --debuginfo
-  --path: "."
-  --run
-
-task test, "run tests":
-  configForTests()
-  setCommand "c", "tests/all.nim"
-
diff --git a/serialization/object_serialization.nim b/serialization/object_serialization.nim
new file mode 100644
index 0000000..156cb54
--- /dev/null
+++ b/serialization/object_serialization.nim
@@ -0,0 +1,52 @@
+import macros
+
+template dontSerialize* {.pragma.}
+  ## Specifies that a certain field should be ignored for
+  ## the purposes of serialization
+
+template customSerialization* {.pragma.}
+  ## This pragma can be applied to a record field to enable the
+  ## use of custom `readValue` overloads that also take a reference
+  ## to the object holding the field.
+  ##
+  ## TODO: deprecate this in favor of readField(T, field, InputArchive)
+
+template eachSerializedFieldImpl*[T](x: T, op: untyped) =
+  for k, v in fieldPairs(x):
+    when not hasCustomPragma(v, dontSerialize):
+      op(k, v)
+
+proc totalSerializedFieldsImpl(T: type): int =
+  mixin eachSerializedFieldImpl
+
+  proc helper: int =
+    var dummy: T
+    template countFields(x) = inc result
+    eachSerializedFieldImpl(dummy, countFields)
+
+  const res = helper()
+  return res
+
+template totalSerializedFields*(T: type): int =
+  (static(totalSerializedFieldsImpl(T)))
+
+macro serialziedFields*(T: typedesc, fields: varargs[untyped]): untyped =
+  var body = newStmtList()
+  let
+    ins = genSym(nskParam, "instance")
+    op = genSym(nskParam, "op")
+
+  for field in fields:
+    body.add quote do: `op`(`ins`.`field`)
+
+  result = quote do:
+    template eachSerializedFieldImpl*(`ins`: `T`, `op`: untyped) {.inject.} =
+      `body`
+
+template serializeFields*(value: auto, fieldName, fieldValue, body: untyped) =
+  # TODO: this would be nicer as a for loop macro
+  mixin eachSerializedFieldImpl
+  
+  template op(fieldName, fieldValue: untyped) = body
+  eachSerializedFieldImpl(value, op)
+