Added support for is_encodable in packed codec

eth_abi/codec.py

@@ -28,12 +28,9 @@
 )
 
 
-class ABICodec():
-    def __init__(self, registry: ABIRegistry=None):
-        if registry is None:
-            self._registry = default_registry
-        else:
-            self._registry = registry
+class BaseABICodecEncoder():
+    def __init__(self, registry):
+        self._registry = registry
 
     def encode_single(self, typ: TypeStr, arg: Any) -> bytes:
         """
@@ -98,6 +95,14 @@ def is_encodable(self, typ: TypeStr, arg: Any) -> bool:
 
         return True
 
+
+class ABICodec(BaseABICodecEncoder):
+    def __init__(self, registry: ABIRegistry=None):
+        if registry is None:
+            BaseABICodecEncoder.__init__(self, default_registry)
+        else:
+            BaseABICodecEncoder.__init__(self, registry)
+
     def decode_single(self, typ: TypeStr, data: Decodable) -> Any:
         """
         Decodes the binary value ``data`` of the ABI type ``typ`` into its

eth_abi/codec_packed.py

@@ -1,17 +1,7 @@
-from typing import (
-    Any,
-    Iterable,
-    Tuple,
-)
 import warnings
 
-from eth_typing.abi import (
-    Decodable,
-    TypeStr,
-)
-
 from eth_abi.codec import (
-    ABICodec,
+    BaseABICodecEncoder,
 )
 from eth_abi.registry import (
     ABIRegistry,
@@ -24,18 +14,9 @@
 )
 
 
-class ABICodecPacked(ABICodec):
+class ABICodecPacked(BaseABICodecEncoder):
     def __init__(self, registry: ABIRegistry=None):
         if registry is None:
-            ABICodec.__init__(self, default_packed_registry)
+            BaseABICodecEncoder.__init__(self, default_packed_registry)
         else:
-            ABICodec.__init__(self, registry)
-
-    def is_encodable(self, typ: TypeStr, arg: Any) -> bool:
-        raise NotImplementedError("'is_encodable' is not  supported in packed mode")
-
-    def decode_single(self, typ: TypeStr, data: Decodable) -> Any:
-        raise NotImplementedError("'decode_single' is not supported in packed mode")
-
-    def decode_abi(self, types: Iterable[TypeStr], data: Decodable) -> Tuple[Any, ...]:
-        raise NotImplementedError("'decode_abi' is not supported in packed mode")
+            BaseABICodecEncoder.__init__(self, registry)

eth_abi/packed.py

@@ -6,3 +6,4 @@
 
 encode_single_packed = default_codec_packed.encode_single
 encode_abi_packed = default_codec_packed.encode_abi
+is_encodable_packed = default_codec_packed.is_encodable