json.match utility procedure

core/encoding/json/match.odin

@@ -0,0 +1,68 @@
+package encoding_json
+
+Match_Key_Variant :: union #no_nil {
+	int,    // Index
+	string, // Key
+}
+
+Match_Error :: enum {
+	None,
+	Invalid_Argument,
+	Invalid_Type_For_Index,
+	Invalid_Type_For_Key,
+	Key_Not_Found,
+	Out_Of_Bounds_Index,
+}
+
+Match_Flags :: distinct bit_set[Match_Flag]
+Match_Flag :: enum {
+	Ignore_Key_Not_Found,
+	Allow_String_Indexing_By_Byte,
+}
+
+@(require_results)
+match :: proc(value: Value, args: ..Match_Key_Variant, flags: Match_Flags = nil) -> (found: Value, err: Match_Error) {
+	found = value
+	arg_loop: for arg in args {
+		switch k in arg {
+		case int:
+			#partial switch v in found {
+			case Array:
+				if 0 <= k && k < len(v) {
+					found = v[k]
+					continue arg_loop
+				}
+				err = .Out_Of_Bounds_Index
+				return
+			case String:
+				if .Allow_String_Indexing_By_Byte in flags {
+					if 0 <= k && k < len(v) {
+						found = Integer(v[k])
+						continue arg_loop
+					}
+					err = .Out_Of_Bounds_Index
+					return
+				}
+			}
+			err = .Invalid_Type_For_Index
+			return
+		case string:
+			v, ok := found.(Object)
+			if !ok {
+				err = .Invalid_Type_For_Key
+				return
+			}
+			vfound, vok := v[k]
+			if vok || (.Ignore_Key_Not_Found in flags) {
+				found = vfound
+				continue arg_loop
+			}
+			err = .Key_Not_Found
+			return
+		case:
+			err = .Invalid_Argument
+			return
+		}
+	}
+	return
+}