How key_hash can be coerced to address, or vice versa?

Question

I try to convert a "key_hash" to "address" data type.

In OCaml syntax like: let key_h = (addr : key_hash) in

and ReasonML syntax like: let key_h = (addr : key_hash);

have the same error:

Type error:  Unexpected type in annotated expression.
Expected type:
    address
Actual type:
    key_hash

I found this advice, but it doesn't solve my problem...

Can I solve this directly? Or only work around?

Thanks in advance!

Answer 1

To convert a key_hash to an address, you can use:

# Liquidity
Contract.address (Account.default k)

# Michelson
IMPLICIT_ACCOUNT; ADDRESS

To convert an address to a key_hash is more difficult. Michelson does not expose any nice way to do this.

Hopefully, a future protocol change will add an operation for this.

For now, it might be best to work around it. Have someone pass a key or key_hash in the parameter instead. If you need to, you can convert to address as above and compare for equality, e.g. to check that a given key_hash matches a SENDER.

If you really want it today, it should be possible to hack it, using Bytes.pack to convert the address to bytes, modifying the bytes a bit, and then using Bytes.unpack to get a key_hash. However, I don't recommend this, so I won't share code for it...