walk: always index

miniconf/src/impls.rs

@@ -17,7 +17,7 @@ macro_rules! impl_tuple {
             fn traverse_all<W: Walk>() -> Result<W, W::Error> {
                 let k = KeyLookup::numbered($n);
                 let mut walk = W::internal();
-                $(walk = walk.merge(&$t::traverse_all()?, Some($i), &k)?;)+
+                $(walk = walk.merge(&$t::traverse_all()?, $i, &k)?;)+
                 Ok(walk)
             }
 
@@ -114,7 +114,7 @@ impl<const L: usize, const R: usize> Assert<L, R> {
 impl<T: TreeKey, const N: usize> TreeKey for [T; N] {
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
         let () = Assert::<N, 0>::GREATER; // internal nodes must have at least one leaf
-        W::internal().merge(&T::traverse_all()?, None, &KeyLookup::homogeneous(N))
+        W::internal().merge(&T::traverse_all()?, 0, &KeyLookup::homogeneous(N))
     }
 
     fn traverse_by_key<K, F, E>(mut keys: K, mut func: F) -> Result<usize, Error<E>>
@@ -248,8 +248,8 @@ impl<T: TreeKey, E: TreeKey> TreeKey for Result<T, E> {
     #[inline]
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
         W::internal()
-            .merge(&T::traverse_all()?, Some(0), &RESULT_LOOKUP)?
-            .merge(&E::traverse_all()?, Some(1), &RESULT_LOOKUP)
+            .merge(&T::traverse_all()?, 0, &RESULT_LOOKUP)?
+            .merge(&E::traverse_all()?, 1, &RESULT_LOOKUP)
     }
 
     #[inline]
@@ -333,8 +333,8 @@ impl<T: TreeKey> TreeKey for Bound<T> {
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
         let t = T::traverse_all()?;
         W::internal()
-            .merge(&t, Some(0), &BOUND_LOOKUP)?
-            .merge(&t, Some(1), &BOUND_LOOKUP)
+            .merge(&t, 0, &BOUND_LOOKUP)?
+            .merge(&t, 1, &BOUND_LOOKUP)
     }
 
     #[inline]
@@ -417,8 +417,8 @@ impl<T: TreeKey> TreeKey for Range<T> {
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
         let t = T::traverse_all()?;
         W::internal()
-            .merge(&t, Some(0), &RANGE_LOOKUP)?
-            .merge(&t, Some(1), &RANGE_LOOKUP)
+            .merge(&t, 0, &RANGE_LOOKUP)?
+            .merge(&t, 1, &RANGE_LOOKUP)
     }
 
     #[inline]
@@ -499,8 +499,8 @@ impl<T: TreeKey> TreeKey for RangeInclusive<T> {
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
         let t = T::traverse_all()?;
         W::internal()
-            .merge(&t, Some(0), &RANGE_LOOKUP)?
-            .merge(&t, Some(1), &RANGE_LOOKUP)
+            .merge(&t, 0, &RANGE_LOOKUP)?
+            .merge(&t, 1, &RANGE_LOOKUP)
     }
 
     #[inline]
@@ -538,7 +538,7 @@ const RANGE_FROM_LOOKUP: KeyLookup = KeyLookup::Named(&["start"]);
 impl<T: TreeKey> TreeKey for RangeFrom<T> {
     #[inline]
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
-        W::internal().merge(&T::traverse_all()?, Some(0), &RANGE_FROM_LOOKUP)
+        W::internal().merge(&T::traverse_all()?, 0, &RANGE_FROM_LOOKUP)
     }
 
     #[inline]
@@ -615,7 +615,7 @@ const RANGE_TO_LOOKUP: KeyLookup = KeyLookup::Named(&["end"]);
 impl<T: TreeKey> TreeKey for RangeTo<T> {
     #[inline]
     fn traverse_all<W: Walk>() -> Result<W, W::Error> {
-        W::internal().merge(&T::traverse_all()?, Some(0), &RANGE_TO_LOOKUP)
+        W::internal().merge(&T::traverse_all()?, 0, &RANGE_TO_LOOKUP)
     }
 
     #[inline]

miniconf/src/trees.rs

@@ -42,21 +42,16 @@ impl Walk for TreeWalk {
     fn leaf() -> Self {
         Self(Tree::new(None))
     }
-    fn merge(
-        mut self,
-        walk: &Self,
-        index: Option<usize>,
-        lookup: &KeyLookup,
-    ) -> Result<Self, Self::Error> {
+    fn merge(mut self, walk: &Self, index: usize, lookup: &KeyLookup) -> Result<Self, Self::Error> {
         if let Some(l) = self.0.root().data() {
             debug_assert_eq!(l, lookup);
         }
         self.0
             .root_mut()
             .data_mut()
             .get_or_insert_with(|| lookup.clone());
-        if let Some(index) = index {
-            debug_assert_eq!(index, self.0.root().degree());
+        if matches!(lookup, KeyLookup::Homogeneous(_)) {
+            debug_assert_eq!(index, 0);
         }
         self.0.push_back(walk.0.clone());
         Ok(self)

miniconf/src/walk.rs

@@ -52,15 +52,9 @@ pub trait Walk: Sized {
     ///
     /// # Args
     /// * `walk`: The walk of the node to merge.
-    /// * `index`: Either the node index in case of a single node
-    ///   or `None`, in case of `lookup.len` nodes of homogeneous type.
+    /// * `index`: Either the child index or zero for homogeneous.
     /// * `lookup`: The namespace the node(s) are in.
-    fn merge(
-        self,
-        walk: &Self,
-        index: Option<usize>,
-        lookup: &KeyLookup,
-    ) -> Result<Self, Self::Error>;
+    fn merge(self, walk: &Self, index: usize, lookup: &KeyLookup) -> Result<Self, Self::Error>;
 }
 
 impl Walk for Metadata {
@@ -80,25 +74,19 @@ impl Walk for Metadata {
     }
 
     #[inline]
-    fn merge(
-        mut self,
-        meta: &Self,
-        index: Option<usize>,
-        lookup: &KeyLookup,
-    ) -> Result<Self, Self::Error> {
-        let (ident_len, count) = match lookup {
-            KeyLookup::Named(names) => (names[index.unwrap()].len(), 1),
-            KeyLookup::Numbered(_len) => (
-                index.unwrap().checked_ilog10().unwrap_or_default() as usize + 1,
-                1,
-            ),
+    fn merge(mut self, meta: &Self, index: usize, lookup: &KeyLookup) -> Result<Self, Self::Error> {
+        let (len, count) = match lookup {
+            KeyLookup::Named(names) => (names[index].len(), 1),
+            KeyLookup::Numbered(_len) => {
+                (index.checked_ilog10().unwrap_or_default() as usize + 1, 1)
+            }
             KeyLookup::Homogeneous(len) => {
-                assert!(index.is_none());
-                (len.get().ilog10() as usize + 1, len.get())
+                debug_assert_eq!(index, 0);
+                (len.ilog10() as usize + 1, len.get())
             }
         };
         self.max_depth = self.max_depth.max(1 + meta.max_depth);
-        self.max_length = self.max_length.max(ident_len + meta.max_length);
+        self.max_length = self.max_length.max(len + meta.max_length);
         debug_assert_ne!(meta.count, 0);
         self.count += count * meta.count;
         self.max_bits = self

miniconf_derive/src/tree.rs

@@ -191,7 +191,7 @@ impl Tree {
             if self.flatten.is_present() {
                 quote!(walk = #w;)
             } else {
-                quote!(walk = walk.merge(&#w, Some(#i), &Self::__MINICONF_LOOKUP)?;)
+                quote!(walk = walk.merge(&#w, #i, &Self::__MINICONF_LOOKUP)?;)
             }
         });
         let traverse_arms = fields.iter().enumerate().map(|(i, f)| f.traverse_by_key(i));