Remove TranslatePk trait and clean up Translator trait

bitcoind-tests/tests/setup/test_util.rs

@@ -26,7 +26,7 @@ use bitcoin::secp256k1;
 use miniscript::descriptor::{SinglePub, SinglePubKey};
 use miniscript::{
     bitcoin, hash256, Descriptor, DescriptorPublicKey, Error, Miniscript, ScriptContext,
-    TranslatePk, Translator,
+    Translator,
 };
 use rand::RngCore;
 use secp256k1::XOnlyPublicKey;
@@ -155,8 +155,11 @@ pub fn parse_insane_ms<Ctx: ScriptContext>(
 #[derive(Debug, Clone)]
 struct StrDescPubKeyTranslator<'a>(usize, &'a PubData);
 
-impl<'a> Translator<String, DescriptorPublicKey, ()> for StrDescPubKeyTranslator<'a> {
-    fn pk(&mut self, pk_str: &String) -> Result<DescriptorPublicKey, ()> {
+impl<'a> Translator<String> for StrDescPubKeyTranslator<'a> {
+    type TargetPk = DescriptorPublicKey;
+    type Error = core::convert::Infallible;
+
+    fn pk(&mut self, pk_str: &String) -> Result<Self::TargetPk, Self::Error> {
         let avail = !pk_str.ends_with('!');
         if avail {
             self.0 += 1;
@@ -181,22 +184,22 @@ impl<'a> Translator<String, DescriptorPublicKey, ()> for StrDescPubKeyTranslator
         }
     }
 
-    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, Self::Error> {
         let sha = sha256::Hash::from_str(sha256).unwrap();
         Ok(sha)
     }
 
-    fn hash256(&mut self, hash256: &String) -> Result<hash256::Hash, ()> {
+    fn hash256(&mut self, hash256: &String) -> Result<hash256::Hash, Self::Error> {
         let hash256 = hash256::Hash::from_str(hash256).unwrap();
         Ok(hash256)
     }
 
-    fn ripemd160(&mut self, ripemd160: &String) -> Result<ripemd160::Hash, ()> {
+    fn ripemd160(&mut self, ripemd160: &String) -> Result<ripemd160::Hash, Self::Error> {
         let ripemd160 = ripemd160::Hash::from_str(ripemd160).unwrap();
         Ok(ripemd160)
     }
 
-    fn hash160(&mut self, hash160: &String) -> Result<hash160::Hash, ()> {
+    fn hash160(&mut self, hash160: &String) -> Result<hash160::Hash, Self::Error> {
         let hash160 = hash160::Hash::from_str(hash160).unwrap();
         Ok(hash160)
     }
@@ -208,8 +211,11 @@ impl<'a> Translator<String, DescriptorPublicKey, ()> for StrDescPubKeyTranslator
 #[derive(Debug, Clone)]
 struct StrTranslatorLoose<'a>(usize, &'a PubData);
 
-impl<'a> Translator<String, DescriptorPublicKey, ()> for StrTranslatorLoose<'a> {
-    fn pk(&mut self, pk_str: &String) -> Result<DescriptorPublicKey, ()> {
+impl<'a> Translator<String> for StrTranslatorLoose<'a> {
+    type TargetPk = DescriptorPublicKey;
+    type Error = core::convert::Infallible;
+
+    fn pk(&mut self, pk_str: &String) -> Result<Self::TargetPk, Self::Error> {
         let avail = !pk_str.ends_with('!');
         if avail {
             self.0 += 1;
@@ -238,22 +244,22 @@ impl<'a> Translator<String, DescriptorPublicKey, ()> for StrTranslatorLoose<'a>
         }
     }
 
-    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, ()> {
+    fn sha256(&mut self, sha256: &String) -> Result<sha256::Hash, Self::Error> {
         let sha = sha256::Hash::from_str(sha256).unwrap();
         Ok(sha)
     }
 
-    fn hash256(&mut self, hash256: &String) -> Result<hash256::Hash, ()> {
+    fn hash256(&mut self, hash256: &String) -> Result<hash256::Hash, Self::Error> {
         let hash256 = hash256::Hash::from_str(hash256).unwrap();
         Ok(hash256)
     }
 
-    fn ripemd160(&mut self, ripemd160: &String) -> Result<ripemd160::Hash, ()> {
+    fn ripemd160(&mut self, ripemd160: &String) -> Result<ripemd160::Hash, Self::Error> {
         let ripemd160 = ripemd160::Hash::from_str(ripemd160).unwrap();
         Ok(ripemd160)
     }
 
-    fn hash160(&mut self, hash160: &String) -> Result<hash160::Hash, ()> {
+    fn hash160(&mut self, hash160: &String) -> Result<hash160::Hash, Self::Error> {
         let hash160 = hash160::Hash::from_str(hash160).unwrap();
         Ok(hash160)
     }

examples/big.rs

@@ -18,7 +18,7 @@ use miniscript::policy::{Concrete, Liftable};
 use miniscript::psbt::PsbtExt;
 use miniscript::{
     translate_hash_fail, DefiniteDescriptorKey, Descriptor, DescriptorPublicKey, MiniscriptKey,
-    TranslatePk, Translator,
+    Translator,
 };
 use secp256k1::Secp256k1;
 fn main() {
@@ -82,12 +82,15 @@ struct StrPkTranslator {
     pk_map: HashMap<String, XOnlyPublicKey>,
 }
 
-impl Translator<String, XOnlyPublicKey, ()> for StrPkTranslator {
-    fn pk(&mut self, pk: &String) -> Result<XOnlyPublicKey, ()> {
+impl Translator<String> for StrPkTranslator {
+    type TargetPk = XOnlyPublicKey;
+    type Error = ();
+
+    fn pk(&mut self, pk: &String) -> Result<XOnlyPublicKey, Self::Error> {
         self.pk_map.get(pk).copied().ok_or(())
     }
 
     // We don't need to implement these methods as we are not using them in the policy.
     // Fail if we encounter any hash fragments. See also translate_hash_clone! macro.
-    translate_hash_fail!(String, XOnlyPublicKey, ());
+    translate_hash_fail!(String, XOnlyPublicKey, Self::Error);
 }

examples/taproot.rs

@@ -8,7 +8,7 @@ use miniscript::bitcoin::secp256k1::rand;
 use miniscript::bitcoin::{Network, WitnessVersion};
 use miniscript::descriptor::DescriptorType;
 use miniscript::policy::Concrete;
-use miniscript::{translate_hash_fail, Descriptor, Miniscript, Tap, TranslatePk, Translator};
+use miniscript::{translate_hash_fail, Descriptor, Miniscript, Tap, Translator};
 
 // Refer to https://github.com/sanket1729/adv_btc_workshop/blob/master/workshop.md#creating-a-taproot-descriptor
 // for a detailed explanation of the policy and it's compilation
@@ -17,14 +17,17 @@ struct StrPkTranslator {
     pk_map: HashMap<String, XOnlyPublicKey>,
 }
 
-impl Translator<String, XOnlyPublicKey, ()> for StrPkTranslator {
-    fn pk(&mut self, pk: &String) -> Result<XOnlyPublicKey, ()> {
+impl Translator<String> for StrPkTranslator {
+    type TargetPk = XOnlyPublicKey;
+    type Error = ();
+
+    fn pk(&mut self, pk: &String) -> Result<XOnlyPublicKey, Self::Error> {
         self.pk_map.get(pk).copied().ok_or(())
     }
 
     // We don't need to implement these methods as we are not using them in the policy.
     // Fail if we encounter any hash fragments. See also translate_hash_clone! macro.
-    translate_hash_fail!(String, XOnlyPublicKey, ());
+    translate_hash_fail!(String, XOnlyPublicKey, Self::Error);
 }
 
 fn main() {

src/descriptor/bare.rs

@@ -23,7 +23,7 @@ use crate::prelude::*;
 use crate::util::{varint_len, witness_to_scriptsig};
 use crate::{
     BareCtx, Error, ForEachKey, FromStrKey, Miniscript, MiniscriptKey, Satisfier, ToPublicKey,
-    TranslateErr, TranslatePk, Translator,
+    TranslateErr, Translator,
 };
 
 /// Create a Bare Descriptor. That is descriptor that is
@@ -92,6 +92,14 @@ impl<Pk: MiniscriptKey> Bare<Pk> {
         let scriptsig_len = self.ms.max_satisfaction_size()?;
         Ok(4 * (varint_len(scriptsig_len) + scriptsig_len))
     }
+
+    /// Converts the keys in the script from one type to another.
+    pub fn translate_pk<T>(&self, t: &mut T) -> Result<Bare<T::TargetPk>, TranslateErr<T::Error>>
+    where
+        T: Translator<Pk>,
+    {
+        Bare::new(self.ms.translate_pk(t)?).map_err(TranslateErr::OuterError)
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Bare<Pk> {
@@ -190,21 +198,6 @@ impl<Pk: MiniscriptKey> ForEachKey<Pk> for Bare<Pk> {
     }
 }
 
-impl<P, Q> TranslatePk<P, Q> for Bare<P>
-where
-    P: MiniscriptKey,
-    Q: MiniscriptKey,
-{
-    type Output = Bare<Q>;
-
-    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Bare<Q>, TranslateErr<E>>
-    where
-        T: Translator<P, Q, E>,
-    {
-        Bare::new(self.ms.translate_pk(t)?).map_err(TranslateErr::OuterError)
-    }
-}
-
 /// A bare PkH descriptor at top level
 #[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
 pub struct Pkh<Pk: MiniscriptKey> {
@@ -260,6 +253,18 @@ impl<Pk: MiniscriptKey> Pkh<Pk> {
         note = "Use max_weight_to_satisfy instead. The method to count bytes was redesigned and the results will differ from max_weight_to_satisfy. For more details check rust-bitcoin/rust-miniscript#476."
     )]
     pub fn max_satisfaction_weight(&self) -> usize { 4 * (1 + 73 + BareCtx::pk_len(&self.pk)) }
+
+    /// Converts the keys in a script from one type to another.
+    pub fn translate_pk<T>(&self, t: &mut T) -> Result<Pkh<T::TargetPk>, TranslateErr<T::Error>>
+    where
+        T: Translator<Pk>,
+    {
+        let res = Pkh::new(t.pk(&self.pk)?);
+        match res {
+            Ok(pk) => Ok(pk),
+            Err(e) => Err(TranslateErr::OuterError(Error::from(e))),
+        }
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Pkh<Pk> {
@@ -391,22 +396,3 @@ impl<Pk: FromStrKey> core::str::FromStr for Pkh<Pk> {
 impl<Pk: MiniscriptKey> ForEachKey<Pk> for Pkh<Pk> {
     fn for_each_key<'a, F: FnMut(&'a Pk) -> bool>(&'a self, mut pred: F) -> bool { pred(&self.pk) }
 }
-
-impl<P, Q> TranslatePk<P, Q> for Pkh<P>
-where
-    P: MiniscriptKey,
-    Q: MiniscriptKey,
-{
-    type Output = Pkh<Q>;
-
-    fn translate_pk<T, E>(&self, t: &mut T) -> Result<Self::Output, TranslateErr<E>>
-    where
-        T: Translator<P, Q, E>,
-    {
-        let res = Pkh::new(t.pk(&self.pk)?);
-        match res {
-            Ok(pk) => Ok(pk),
-            Err(e) => Err(TranslateErr::OuterError(Error::from(e))),
-        }
-    }
-}

src/descriptor/key.rs

@@ -1003,9 +1003,7 @@ impl DefiniteDescriptorKey {
     /// always return a compressed key
     ///
     /// Will return an error if the descriptor key has any hardened derivation steps in its path. To
-    /// avoid this error you should replace any such public keys first with [`translate_pk`].
-    ///
-    /// [`translate_pk`]: crate::TranslatePk::translate_pk
+    /// avoid this error you should replace any such public keys first with [`crate::Descriptor::translate_pk`].
     pub fn derive_public_key<C: Verification>(
         &self,
         secp: &Secp256k1<C>,