Codec.Scale

The SCALE (Simple Concatenated Aggregate Little-Endian) Codec is a lightweight, efficient, binary serialization and deserialization codec.

It is designed for high-performance, copy-free encoding and decoding of data in resource-constrained execution contexts, like the Substrate runtime. It is not self-describing in any way and assumes the decoding context has all type knowledge about the encoded data.

Documentation

encode :: (Encode a, ByteArray ba) => a -> ba

Encode datatype to SCALE format.

decode :: (ByteArrayAccess ba, Decode a) => ba -> Either String a

Decode datatype from SCALE format.

encode' :: (Generic a, Rep a ~ rep, GEncode rep, ByteArray ba) => a -> ba

Generic driven version of encode

decode' :: (Generic a, Rep a ~ rep, GDecode rep, ByteArrayAccess ba) => ba -> Either String a

Generic driven version of decode

class Encode a

A class for encoding datatypes to SCALE format.

If your compiler has support for the DeriveGeneric and DefaultSignatures language extensions (ghc >= 7.2.1), the put method will have default generic implementations.

To use this option, simply add a deriving Generic clause to your datatype and declare a Encode instance for it without giving a definition for put.

Instances

Encode Bool

Defined in Codec.Scale.Core

Methods

put :: Putter Bool

Encode Int8

Defined in Codec.Scale.Core

Methods

put :: Putter Int8

Encode Int16

Defined in Codec.Scale.Core

Methods

put :: Putter Int16

Encode Int32

Defined in Codec.Scale.Core

Methods

put :: Putter Int32

Encode Int64

Defined in Codec.Scale.Core

Methods

put :: Putter Int64

Encode Word8

Defined in Codec.Scale.Core

Methods

put :: Putter Word8

Encode Word16

Defined in Codec.Scale.Core

Methods

put :: Putter Word16

Encode Word32

Defined in Codec.Scale.Core

Methods

put :: Putter Word32

Encode Word64

Defined in Codec.Scale.Core

Methods

put :: Putter Word64

Encode ()

Defined in Codec.Scale.Core

Methods

put :: Putter ()

Encode ByteString

Defined in Codec.Scale.Core

Methods

put :: Putter ByteString

Encode Text

Defined in Codec.Scale.Core

Methods

put :: Putter Text

Encode a => Encode [a]

Defined in Codec.Scale.Core

Methods

put :: Putter [a]

Encode (Maybe Bool)

Defined in Codec.Scale.Core

Methods

put :: Putter (Maybe Bool)

Encode a => Encode (Maybe a)

Defined in Codec.Scale.Core

Methods

put :: Putter (Maybe a)

(Encode a, Unbox a) => Encode (Vector a)

Defined in Codec.Scale.Core

Methods

put :: Putter (Vector a)

Encode (Vector Bit)

Defined in Codec.Scale.Core

Methods

put :: Putter (Vector Bit)

Integral a => Encode (Compact a)

Defined in Codec.Scale.Compact

Methods

put :: Putter (Compact a)

Encode a => Encode (SingletonEnum a)

Defined in Codec.Scale.SingletonEnum

Methods

put :: Putter (SingletonEnum a)

Encode (Skip a)

Defined in Codec.Scale.Skip

Methods

put :: Putter (Skip a)

(Encode a, Encode b) => Encode (Either a b)

Defined in Codec.Scale.Core

Methods

put :: Putter (Either a b)

(Encode a1, Encode a2) => Encode (a1, a2)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2)

(Encode a1, Encode a2, Encode a3) => Encode (a1, a2, a3)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3)

(Encode a1, Encode a2, Encode a3, Encode a4) => Encode (a1, a2, a3, a4)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5) => Encode (a1, a2, a3, a4, a5)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6) => Encode (a1, a2, a3, a4, a5, a6)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7) => Encode (a1, a2, a3, a4, a5, a6, a7)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8) => Encode (a1, a2, a3, a4, a5, a6, a7, a8)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15, Encode a16) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15, Encode a16, Encode a17) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15, Encode a16, Encode a17, Encode a18) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15, Encode a16, Encode a17, Encode a18, Encode a19) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19)

(Encode a1, Encode a2, Encode a3, Encode a4, Encode a5, Encode a6, Encode a7, Encode a8, Encode a9, Encode a10, Encode a11, Encode a12, Encode a13, Encode a14, Encode a15, Encode a16, Encode a17, Encode a18, Encode a19, Encode a20) => Encode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)

Defined in Codec.Scale.Core

Methods

put :: Putter (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)

class Decode a

A class for decoding datatypes from SCALE format.

If your compiler has support for the DeriveGeneric and DefaultSignatures language extensions (ghc >= 7.2.1), the get method will have default generic implementations.

To use this option, simply add a deriving Generic clause to your datatype and declare a Decode instance for it without giving a definition for get.

Instances

Decode Bool

Defined in Codec.Scale.Core

Methods

get :: Get Bool

Decode Int8

Defined in Codec.Scale.Core

Methods

get :: Get Int8

Decode Int16

Defined in Codec.Scale.Core

Methods

get :: Get Int16

Decode Int32

Defined in Codec.Scale.Core

Methods

get :: Get Int32

Decode Int64

Defined in Codec.Scale.Core

Methods

get :: Get Int64

Decode Word8

Defined in Codec.Scale.Core

Methods

get :: Get Word8

Decode Word16

Defined in Codec.Scale.Core

Methods

get :: Get Word16

Decode Word32

Defined in Codec.Scale.Core

Methods

get :: Get Word32

Decode Word64

Defined in Codec.Scale.Core

Methods

get :: Get Word64

Decode ()

Defined in Codec.Scale.Core

Methods

get :: Get ()

Decode ByteString

Defined in Codec.Scale.Core

Methods

get :: Get ByteString

Decode Text

Defined in Codec.Scale.Core

Methods

get :: Get Text

Decode a => Decode [a]

Defined in Codec.Scale.Core

Methods

get :: Get [a]

Decode (Maybe Bool)

Defined in Codec.Scale.Core

Methods

get :: Get (Maybe Bool)

Decode a => Decode (Maybe a)

Defined in Codec.Scale.Core

Methods

get :: Get (Maybe a)

(Decode a, Unbox a) => Decode (Vector a)

Defined in Codec.Scale.Core

Methods

get :: Get (Vector a)

Decode (Vector Bit)

Defined in Codec.Scale.Core

Methods

get :: Get (Vector Bit)

Integral a => Decode (Compact a)

Defined in Codec.Scale.Compact

Methods

get :: Get (Compact a)

Decode a => Decode (SingletonEnum a)

Defined in Codec.Scale.SingletonEnum

Methods

get :: Get (SingletonEnum a)

Default a => Decode (Skip a)

Defined in Codec.Scale.Skip

Methods

get :: Get (Skip a)

(Decode a, Decode b) => Decode (Either a b)

Defined in Codec.Scale.Core

Methods

get :: Get (Either a b)

(Decode a1, Decode a2) => Decode (a1, a2)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2)

(Decode a1, Decode a2, Decode a3) => Decode (a1, a2, a3)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3)

(Decode a1, Decode a2, Decode a3, Decode a4) => Decode (a1, a2, a3, a4)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5) => Decode (a1, a2, a3, a4, a5)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6) => Decode (a1, a2, a3, a4, a5, a6)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7) => Decode (a1, a2, a3, a4, a5, a6, a7)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8) => Decode (a1, a2, a3, a4, a5, a6, a7, a8)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15, Decode a16) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15, Decode a16, Decode a17) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15, Decode a16, Decode a17, Decode a18) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15, Decode a16, Decode a17, Decode a18, Decode a19) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19)

(Decode a1, Decode a2, Decode a3, Decode a4, Decode a5, Decode a6, Decode a7, Decode a8, Decode a9, Decode a10, Decode a11, Decode a12, Decode a13, Decode a14, Decode a15, Decode a16, Decode a17, Decode a18, Decode a19, Decode a20) => Decode (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)

Defined in Codec.Scale.Core

Methods

get :: Get (a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20)

class All (SListI :: [Type] -> Constraint) (Code a) => Generic a

The class of representable datatypes.

The SOP approach to generic programming is based on viewing datatypes as a representation (Rep) built from the sum of products of its components. The components of a datatype are specified using the Code type family.

The isomorphism between the original Haskell datatype and its representation is witnessed by the methods of this class, from and to. So for instances of this class, the following laws should (in general) hold:

to . from === id :: a -> a
from . to === id :: Rep a -> Rep a

You typically don't define instances of this class by hand, but rather derive the class instance automatically.

Option 1: Derive via the built-in GHC-generics. For this, you need to use the DeriveGeneric extension to first derive an instance of the Generic class from module GHC.Generics. With this, you can then give an empty instance for Generic, and the default definitions will just work. The pattern looks as follows:

import qualified GHC.Generics as GHC
import Generics.SOP

...

data T = ... deriving (GHC.Generic, ...)

instance Generic T -- empty
instance HasDatatypeInfo T -- empty, if you want/need metadata

Option 2: Derive via Template Haskell. For this, you need to enable the TemplateHaskell extension. You can then use deriveGeneric from module Generics.SOP.TH to have the instance generated for you. The pattern looks as follows:

import Generics.SOP
import Generics.SOP.TH

...

data T = ...

deriveGeneric ''T -- derives HasDatatypeInfo as well

Tradeoffs: Whether to use Option 1 or 2 is mainly a matter of personal taste. The version based on Template Haskell probably has less run-time overhead.

Non-standard instances: It is possible to give Generic instances manually that deviate from the standard scheme, as long as at least

to . from === id :: a -> a

still holds.

module Codec.Scale.Core