Separate taptree in identifiers and docs

We use `TapTree` therefore the all lowercase version should be
`tap_tree` not `taptree`.

Author: tcharding

examples/taproot.rs

@@ -101,7 +101,7 @@ fn main() {
     let real_desc = desc.translate_pk(&mut t).unwrap();
 
     // Max satisfaction weight for compilation, corresponding to the script-path spend
-    // `multi_a(2,PUBKEY_1,PUBKEY_2) at taptree depth 1, having:
+    // `multi_a(2,PUBKEY_1,PUBKEY_2) at tap tree depth 1, having:
     //
     //     max_witness_size = varint(control_block_size) + control_block size +
     //                        varint(script_size) + script_size + max_satisfaction_size

src/descriptor/tr.rs

@@ -110,11 +110,11 @@ impl<Pk: MiniscriptKey> hash::Hash for Tr<Pk> {
 impl<Pk: MiniscriptKey> TapTree<Pk> {
     // Helper function to compute height
     // TODO: Instead of computing this every time we add a new leaf, we should
-    // add height as a separate field in taptree
-    fn taptree_height(&self) -> usize {
+    // add height as a separate field in tap tree
+    fn tap_tree_height(&self) -> usize {
         match *self {
             TapTree::Tree(ref left_tree, ref right_tree) => {
-                1 + max(left_tree.taptree_height(), right_tree.taptree_height())
+                1 + max(left_tree.tap_tree_height(), right_tree.tap_tree_height())
             }
             TapTree::Leaf(..) => 0,
         }
@@ -167,7 +167,7 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
     /// Create a new [`Tr`] descriptor from internal key and [`TapTree`]
     pub fn new(internal_key: Pk, tree: Option<TapTree<Pk>>) -> Result<Self, Error> {
         Tap::check_pk(&internal_key)?;
-        let nodes = tree.as_ref().map(|t| t.taptree_height()).unwrap_or(0);
+        let nodes = tree.as_ref().map(|t| t.tap_tree_height()).unwrap_or(0);
 
         if nodes <= TAPROOT_CONTROL_MAX_NODE_COUNT {
             Ok(Self {
@@ -186,7 +186,7 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
     }
 
     /// Obtain the [`TapTree`] of the [`Tr`] descriptor
-    pub fn taptree(&self) -> &Option<TapTree<Pk>> {
+    pub fn tap_tree(&self) -> &Option<TapTree<Pk>> {
         &self.tree
     }
 
@@ -258,7 +258,7 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
     /// # Errors
     /// When the descriptor is impossible to safisfy (ex: sh(OP_FALSE)).
     pub fn max_weight_to_satisfy(&self) -> Result<usize, Error> {
-        let tree = match self.taptree() {
+        let tree = match self.tap_tree() {
             None => {
                 // key spend path
                 // item: varint(sig+sigHash) + <sig(64)+sigHash(1)>
@@ -309,7 +309,7 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
     /// When the descriptor is impossible to safisfy (ex: sh(OP_FALSE)).
     #[deprecated(note = "use max_weight_to_satisfy instead")]
     pub fn max_satisfaction_weight(&self) -> Result<usize, Error> {
-        let tree = match self.taptree() {
+        let tree = match self.tap_tree() {
             // key spend path:
             // scriptSigLen(4) + stackLen(1) + stack[Sig]Len(1) + stack[Sig](65)
             None => return Ok(4 + 1 + 1 + 65),

src/policy/concrete.rs

@@ -387,7 +387,7 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
             _ => {
                 let (internal_key, policy) = self.clone().extract_key(unspendable_key)?;
                 policy.check_num_tapleaves()?;
-                let tree = Descriptor::new_tr(
+                let tap_tree = Descriptor::new_tr(
                     internal_key,
                     match policy {
                         Policy::Trivial => None,
@@ -403,12 +403,12 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
                                 compilation.sanity_check()?;
                                 leaf_compilations.push((OrdF64(prob), compilation));
                             }
-                            let taptree = with_huffman_tree::<Pk>(leaf_compilations)?;
-                            Some(taptree)
+                            let tree = with_huffman_tree::<Pk>(leaf_compilations)?;
+                            Some(tree)
                         }
                     },
                 )?;
-                Ok(tree)
+                Ok(tap_tree)
             }
         }
     }
@@ -444,7 +444,7 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
             )),
             _ => {
                 let (internal_key, policy) = self.clone().extract_key(unspendable_key)?;
-                let tree = Descriptor::new_tr(
+                let tap_tree = Descriptor::new_tr(
                     internal_key,
                     match policy {
                         Policy::Trivial => None,
@@ -462,12 +462,12 @@ impl<Pk: MiniscriptKey> Policy<Pk> {
                                     )
                                 })
                                 .collect();
-                            let taptree = with_huffman_tree::<Pk>(leaf_compilations).unwrap();
-                            Some(taptree)
+                            let tree = with_huffman_tree::<Pk>(leaf_compilations).unwrap();
+                            Some(tree)
                         }
                     },
                 )?;
-                Ok(tree)
+                Ok(tap_tree)
             }
         }
     }

src/psbt/mod.rs

@@ -1222,7 +1222,7 @@ fn update_item_with_descriptor_helper<F: PsbtFields>(
             match item.tap_tree() {
                 // Only set the tap_tree if the item supports it (it's an output) and the descriptor actually
                 // contains one, otherwise it'll just be empty
-                Some(tap_tree) if tr_derived.taptree().is_some() => {
+                Some(tap_tree) if tr_derived.tap_tree().is_some() => {
                     *tap_tree = Some(
                         taproot::TapTree::try_from(builder)
                             .expect("The tree should always be valid"),