Macro miniscript::translate_hash_fail

macro_rules! translate_hash_fail {
    ($source: ty, $target:ty, $error_ty: ty) => { ... };
}

Macro for failing translation for other associated types. Handy for testing String -> concrete keys as we don’t want to specify these functions repeatedly.

This macro is handy when dealing with scripts that are only contain keys. See also crate::translate_hash_clone

use miniscript::{bitcoin::PublicKey, policy::concrete::Policy, Translator, hash256};
use std::str::FromStr;
use miniscript::translate_hash_fail;
use std::collections::HashMap;
use miniscript::bitcoin::hashes::{sha256, hash160, ripemd160};
let alice_key = "0270cf3c71f65a3d93d285d9149fddeeb638f87a2d4d8cf16c525f71c417439777";
let bob_key = "02f43b15c50a436f5335dbea8a64dd3b4e63e34c3b50c42598acb5f4f336b5d2fb";
let placeholder_policy = Policy::<String>::from_str("and(pk(alice_key),pk(bob_key))").unwrap();

// Information to translator abstract String type keys to concrete bitcoin::PublicKey.
// In practice, wallets would map from String key names to BIP32 keys
struct StrPkTranslator {
    pk_map: HashMap<String, bitcoin::PublicKey>
}

// If we also wanted to provide mapping of other associated types(sha256, older etc),
// we would use the general Translator Trait.
impl Translator<String, bitcoin::PublicKey, ()> for StrPkTranslator {
    // Provides the translation public keys P -> Q
    fn pk(&mut self, pk: &String) -> Result<bitcoin::PublicKey, ()> {
        self.pk_map.get(pk).copied().ok_or(()) // Dummy Err
    }

    // Fail for hash types
    translate_hash_fail!(String, bitcoin::PublicKey, ());
}

let mut pk_map = HashMap::new();
pk_map.insert(String::from("alice_key"), bitcoin::PublicKey::from_str(alice_key).unwrap());
pk_map.insert(String::from("bob_key"), bitcoin::PublicKey::from_str(bob_key).unwrap());
let mut t = StrPkTranslator { pk_map: pk_map };