From cee87c22293ad78b5205eb12dc169fe7e347c1c7 Mon Sep 17 00:00:00 2001
From: Brendan Hansen <brendan.f.hansen@gmail.com>
Date: Sun, 11 Jun 2023 22:00:25 -0500
Subject: [PATCH] added: support for optionals in json encoder/decoder

---
 core/encoding/json/encoder.onyx | 43 +++++++++++++++++++++++++++++++++
 core/misc/any_utils.onyx        |  2 +-
 core/runtime/info/helper.onyx   |  8 ++++++
 tests/json_test                 |  3 +++
 tests/json_test.onyx            | 18 +++++++++++++-
 5 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/core/encoding/json/encoder.onyx b/core/encoding/json/encoder.onyx
index 60baaf1b..c596fe1e 100644
--- a/core/encoding/json/encoder.onyx
+++ b/core/encoding/json/encoder.onyx
@@ -230,6 +230,20 @@ encode :: (w: ^io.Writer, data: any) -> Encoding_Error {
             io.write(w, "}");
         }
 
+        case .Union {
+            if !union_constructed_from(data.type, Optional) {
+                return .Unsupported_Type;
+            }
+
+            u := info->as_union();
+            tag := *cast(&Optional(void).tag_enum) data.data;
+            if tag != .Some {
+                io.write(w, "null");
+            } else {
+                encode(w, misc.any_member(data, u.variants[1].type, u.alignment));
+            }
+        }
+
         case #default {
             return .Unsupported_Type;
         }
@@ -350,6 +364,20 @@ from_any :: (type: type_expr, in: rawptr, allocator := context.allocator) -> Val
             d_info := cast(^Type_Info_Distinct) t_info;
             return from_any(d_info.base_type, in);
         }
+
+        case .Union {
+            if !union_constructed_from(type, Optional) {
+                return null_value();
+            }
+
+            u := t_info->as_union();
+            tag := *cast(&Optional(void).tag_enum) in;
+            if tag != .Some {
+                return null_value();
+            } else {
+                return from_any(u.variants[1].type, memory.ptr_add(in, u.alignment), allocator);
+            }
+        }
     }
 
     return null_value();
@@ -447,5 +475,20 @@ as_any :: (value: Value, type: type_expr, out: rawptr) {
             d_info := cast(^Type_Info_Distinct) t_info;
             to_any(value, d_info.base_type, out);
         }
+
+        case .Union {
+            if !union_constructed_from(type, Optional) {
+                return;
+            }
+
+            u_info := t_info->as_union();
+            if value->is_null() {
+                *cast(& ? void) out = .{};
+                return;
+            } else {
+                *cast(&Optional(void).tag_enum) out = .Some;
+                to_any(value, u_info.variants[1].type, memory.ptr_add(out, u_info.alignment));
+            }
+        }
     }
 }
diff --git a/core/misc/any_utils.onyx b/core/misc/any_utils.onyx
index 4c18a626..b0564b3c 100644
--- a/core/misc/any_utils.onyx
+++ b/core/misc/any_utils.onyx
@@ -89,7 +89,7 @@ any_nested_selector :: (v: any, member_name: str) -> any {
 #doc """
 """
 any_member :: #match #locked {
-    macro (v: any, member_type: type_expr, member_offset: u32) -> any {
+    (v: any, member_type: type_expr, member_offset: u32) -> any {
         return any.{
             cast([&] u8, v.data) + member_offset,
             member_type
diff --git a/core/runtime/info/helper.onyx b/core/runtime/info/helper.onyx
index d97bbf21..74fb82ae 100644
--- a/core/runtime/info/helper.onyx
+++ b/core/runtime/info/helper.onyx
@@ -261,6 +261,14 @@ struct_inherits :: (struct_type: type_expr, base_type: type_expr) -> bool {
     return first_member.used && first_member.type == base_type;
 }
 
+union_constructed_from :: (union_type: type_expr, base_type: type_expr) -> bool {
+    union_info := get_type_info(union_type);
+    if union_info.kind != .Union do return false;
+
+    return (cast(&Type_Info_Union) union_info).constructed_from == base_type;
+}
+
+
 #operator == (t1: Type_Info_Function, t2: Type_Info_Function) -> bool {
     if t1.parameter_types.count != t2.parameter_types.count do return false;
     if t1.return_type           != t2.return_type           do return false;
diff --git a/tests/json_test b/tests/json_test
index 29001aa4..2ac867d5 100644
--- a/tests/json_test
+++ b/tests/json_test
@@ -4,3 +4,6 @@
 {"test":"Wow!","working":123,"data":[1,2,3,4,5],"people":[{"name":"Joe"},{"name":"Bob"}],"other":[{"x":1},{"x":2}]}
 {"foo":{"data":5}}
 🂡
+main.Union_Test { v1 = None, v2 = Some(123) }
+{"v1":null,"v2":123}
+{"v1":null,"v2":123}
diff --git a/tests/json_test.onyx b/tests/json_test.onyx
index 40320838..c471c0a7 100644
--- a/tests/json_test.onyx
+++ b/tests/json_test.onyx
@@ -42,7 +42,23 @@ main :: () {
     json.set(o, "foo", json.from_any(^.{data=5}));
     json.encode(^core.stdio.print_writer, o);
 
-    v := json.decode_with_error("""{ "key1": "\\uD83C\\uDCA1", "key2": "\\u264C" }""");
+    v := json.decode_with_error("{ \"key1\": \"\\uD83C\\uDCA1\", \"key2\": \"\\u264C\" }");
     core.print("\n");
     core.println(v.root["key1"]->as_str());
+
+
+    Union_Test :: struct {
+        v1: ? i32;
+        v2: ? i32;
+    }
+
+    ut_json := json.decode_with_error("""{ "v1": null, "v2": 123 }""");
+    ut: Union_Test;
+    json.as_any(ut_json.root, &ut);
+    core.println(ut);
+
+    json.encode(&core.stdio.print_writer, ut_json.root);
+    core.print("\n");
+    json.encode(&core.stdio.print_writer, ut);
+    core.print("\n");
 }
-- 
2.25.1