VIP: Allow list of byte arrays

[ElianaTroper]

Preamble

VIP: 728
Title: Allow list of byte arrays
Author: Samuel Troper, [email protected]
Type: Standard Track
Status: Draft
Created: 2018-03-29

Simple Summary

Allow list of byte arrays.

Abstract

Currently, lists are not allowed for byte arrays. Say you wanted to represent 3 two byte pieces of data, you could use aByteArray: bytes <= 6 and use bytes 1 & 2, 3 & 4, and 5 & 6 as pairs to represent each of these pieces of data, but this is less intuitive to code, less readable, and requires good documentation to allow contracts to be easily readable.

Motivation

This is a limitation of the language, particularly in a space where storage limitations are important, that could easily be addressed. It would also greatly enhance audibility.

Specification

With #714:
someBytes: bytes[2][3]

Backwards Compatibility

Backwards compatible. The old workaround would continue to function, the new implementation would be new.

Copyright

Copyright and related rights waived via CC0

[jamesray1]

I think it's better to just stick to someBytes: bytes[3] rather than someBytes: bytes <= 3. Less overhead, better performance. Note also: #714.

[jacqueswww]

bytes[2][3] does seem ambiguous. The first [] sets the byte length and the second [] set the number of items in the list, but this is a rarer case, and therefore I am OK with it ;)

[jacqueswww]

Tested; works now 👍