deserialize non-prefixed stuint (#10)

serde/json/deserializer.nim

@@ -126,10 +126,11 @@ proc fromJson*[N: static[int], T: array[N, byte]](_: type T, json: JsonNode): ?!
 proc fromJson*[T: distinct](_: type T, json: JsonNode): ?!T =
   success T(?T.distinctBase.fromJson(json))
 
-proc fromJson*[N: static[int], T: StUint[N]](_: type T, json: JsonNode): ?!T =
+proc fromJson*(T: typedesc[StUint or StInt], json: JsonNode): ?!T =
   expectJsonKind(T, JString, json)
   let jsonStr = json.getStr
-  let prefix = jsonStr[0 .. 1].toLowerAscii
+  let prefix = if jsonStr.len >= 2: jsonStr[0 .. 1].toLowerAscii
+               else: jsonStr
   case prefix
   of "0x":
     catch parse(jsonStr, T, 16)

tests/json/testDeserialize.nim

@@ -19,10 +19,30 @@ suite "json serialization - deserialize":
     let json = newJString("Second")
     check !MyEnum.fromJson(json) == Second
 
+  test "deserializes UInt256 with no prefix":
+    let json = newJString("1")
+    check !UInt256.fromJson(json) == 1.u256
+
+  test "deserializes UInt256 from hex string representation":
+    let json = newJString("0x1")
+    check !UInt256.fromJson(json) == 0x1.u256
+
+  test "deserializes UInt256 from octal string representation":
+    let json = newJString("0o1")
+    check !UInt256.fromJson(json) == 0o1.u256
+
+  test "deserializes UInt256 from binary string representation":
+    let json = newJString("0b1")
+    check !UInt256.fromJson(json) == 0b1.u256
+
   test "deserializes UInt256 from non-hex string representation":
     let json = newJString("100000")
     check !UInt256.fromJson(json) == 100000.u256
 
+  test "deserializes Int256 with no prefix":
+    let json = newJString("1")
+    check !Int256.fromJson(json) == 1.i256
+
   test "deserializes Option[T] when has a value":
     let json = newJInt(1)
     check (!fromJson(?int, json) == some 1)