No C introspection library for Token instructions

[garious]

Problem

People creating currencies with Token will want Ledger Wallet support. To get there, the Ledger Wallet app will need to parse Token instructions. It's easiest in C, though Rust is technically possible. Here's how we parse System, Stake, etc:

https://github.com/solana-labs/ledger-app-solana/tree/master/libsol

Proposed Solution

Add an equivalent to libsol for Token instructions.

cc: @jackcmay @t-nelson

[jackcmay]

@t-nelson the C bindings for Token are in (#48), how would you like these to be communicated/linked with Ledger Wallet app?

[jackcmay]

@t-nelson Ping

[t-nelson]

@t-nelson Ping

@jackcmay Whoops! Sorry, I missed your initial comment.

How do we plan on releasing the C bindings?

One thing I notice missing is some sort of versioning symbol. Is that something cbindgen can generate for us?

[jackcmay]

@t-nelson Version added in f083260

How would you like these binding to be shared with the ledger wallet?

[t-nelson]

@jackcmay are we planning to publish the bindings separately from the crate? If not and we don't have any other consumers, I'd just as soon take a copy from the crate. Welcome to suggestions though!

[jackcmay]

Copy from the crate is probably fine since they are versioned. Might also be a good idea to put in the program id of the token program that corresponds to this program

[t-nelson]

Copy from the crate is probably fine since they are versioned.

WFM! 👍

Might also be a good idea to put in the program id of the token program that corresponds to this program

💯

Can cbindgen output the byte string as a preprocessor macro? So far, I've been handling the program IDs like this to facilitate test writing

[jackcmay]

@t-nelson I don't have high hopes that we can do that given my past efforts