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. There is also a Decode function for each type. Note that the type to which data should be decoded is inferred by the context, it is not self-contained in the SCALE encoded data.

One exception is the Tuple type, which does not have methods attached, but instead, there are EncodeTuple / DecodeTuple functions that can be called with any custom struct that embeds the Tuple interface.

Implementation Notes

custom defined types and usage of generics help to minimize the reflection usage.
there is a FixedSequence type (with the same representation as the Sequence type), but it makes possible encoding of arrays (which are fixed-size sequences) that can not be represented by the Sequence type. Note that there are no type checks on the size

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

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

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

radkomih / goscale