SCALE codec implementation in Go compatible with a Tinygo based toolchain

The SCALE types in Go are represented by a set of custom-defined types that implement the Encodable interface. Each type also has a corresponding decode function using the convention Decode<TypeName>. Note that the type to which data should be decoded is inferred from the context and is not self-contained in the SCALE-encoded data.

One exception is the Tuple type. It doesn't have methods attached. Instead, there are EncodeTuple and DecodeTuple functions that can be invoked with any custom struct that embeds the Tuple interface.

Some quirks deserve mention. For example, the FixedSequence type, which has the same representation as the Sequence type, facilitates the encoding of arrays. As arrays are fixed-size sequences, they cannot be encoded as the Sequence type. Note that there are no type checks on the size.

The use of custom-defined types and generics reduces reliance on reflection, which isn't fully supported by TinyGo.

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Boolean

SCALE/Rust	Go
bool	goscale.Bool

Fixed Length Integers

SCALE/Rust	Go
i8	goscale.I8
u8	goscale.U8
i16	goscale.I16
u16	goscale.U16
i32	goscale.I32
u32	goscale.U32
i64	goscale.I64
u64	goscale.U64
i128	goscale.I128
u128	goscale.U128

Length and Compact (Variable Width Integers)

SCALE/Rust	Go
Compact<u8>	goscale.Compact
Compact<u16>	goscale.Compact
Compact<u32>	goscale.Compact
Compact<u64>	goscale.Compact
Compact<u128>	goscale.Compact

Sequence

SCALE/Rust	Go
bytes	goscale.Sequence[U8]
[u8; u8]	goscale.FixedSequence[U8]
string	goscale.Str

Dictionary

SCALE/Rust	Go
	goscale.Dictionary[K, V]

Empty

SCALE/Rust	Go
	goscale.Empty

VaryingData

SCALE/Rust	Go
Enumeration(tagged-union)	goscale.VaryingData

Option

SCALE/Rust	Go
Option<bool>	Option[goscale.Bool]
Option<i8>	Option[goscale.I8]
Option<u8>	Option[goscale.U8]
Option<i16>	Option[goscale.I16]
Option<u16>	Option[goscale.U16]
Option<i32>	Option[goscale.I32]
Option<u32>	Option[goscale.U32]
Option<i64>	Option[goscale.I64]
Option<u64>	Option[goscale.U64]
Option<i128>	Option[goscale.I128]
Option<u128>	Option[goscale.U128]
Option<bytes>	Option[Sequence[U8]]
OptionBool	OptionBool
None	nil

Result

SCALE/Rust	Go
Result<EncodeLike, EncodeLike>	goscale.Result[goscale.Encodable]

Tuple

Go structs are encoded as SCALE Tuple, where each struct field is encoded in a sequence containing all the fields. To decode SCALE encoded structs, it is required to have prior knowledge of the destination data type.

SCALE	Go
struct	goscale.Tuple

Run Tests

go test -v