make tree ops public

src/formula.rs

@@ -25,9 +25,6 @@ use crate::scopeck::Hyp;
 use crate::segment_set::SegmentSet;
 use crate::statement::SymbolType;
 use crate::statement::TokenIter;
-use crate::tree::NodeId;
-use crate::tree::SiblingIter;
-use crate::tree::Tree;
 use crate::util::fast_extend;
 use crate::util::HashMap;
 use crate::verify::ProofBuilder;
@@ -40,6 +37,10 @@ use std::iter::FromIterator;
 use std::ops::Range;
 use std::sync::Arc;
 
+pub use crate::tree::NodeId;
+pub use crate::tree::SiblingIter;
+pub use crate::tree::Tree;
+
 /// An atom representing a typecode (for "set.mm", that's one of 'wff', 'class', 'setvar' or '|-')
 pub type TypeCode = Atom;
 
@@ -163,8 +164,10 @@ impl<'a> Debug for SubstitutionsRef<'a> {
 #[derive(Clone, Default, Debug)]
 pub struct Formula {
     typecode: TypeCode,
-    tree: Arc<Tree<Label>>,
-    root: NodeId,
+    /// The underlying tree structure.
+    pub tree: Arc<Tree<Label>>,
+    /// The root of the tree
+    pub root: NodeId,
     variables: Bitset,
 }
 

src/tree.rs

@@ -3,7 +3,8 @@
 use core::ops::Index;
 use core::ops::IndexMut;
 
-pub(crate) type NodeId = usize;
+/// An index into the tree.
+pub type NodeId = usize;
 
 #[derive(Debug)]
 struct TreeNode<TreeItem> {
@@ -14,7 +15,7 @@ struct TreeNode<TreeItem> {
 
 /// A tree implementation, hopefully efficient for representing formulas
 #[derive(Debug)]
-pub(crate) struct Tree<TreeItem> {
+pub struct Tree<TreeItem> {
     nodes: Vec<TreeNode<TreeItem>>,
 }
 
@@ -50,7 +51,7 @@ impl<TreeItem> Tree<TreeItem> {
 
     /// Checked accessor to a tree node
     #[inline]
-    fn node(&self, node_id: NodeId) -> &'_ TreeNode<TreeItem> {
+    fn node(&self, node_id: NodeId) -> &TreeNode<TreeItem> {
         assert!(node_id > 0, "Cannot index null node!");
         assert!(node_id <= self.nodes.len(), "Cannot index outside of tree!");
         &self.nodes[node_id - 1]
@@ -65,7 +66,8 @@ impl<TreeItem> Tree<TreeItem> {
     }
 
     /// iterator through the children of the given node
-    pub(crate) fn children_iter(&self, node_id: NodeId) -> SiblingIter<'_, TreeItem> {
+    #[must_use]
+    pub fn children_iter(&self, node_id: NodeId) -> SiblingIter<'_, TreeItem> {
         SiblingIter {
             tree: self,
             current_id: self.first_child(node_id),
@@ -74,15 +76,17 @@ impl<TreeItem> Tree<TreeItem> {
 
     /// returns the next sibling node id, or `None` if this is the last sibling.
     /// This executes in O(1)
-    pub(crate) fn next_sibling(&self, node_id: NodeId) -> Option<NodeId> {
+    #[must_use]
+    pub fn next_sibling(&self, node_id: NodeId) -> Option<NodeId> {
         match self.node(node_id).next_sibling {
             0 => None,
             node_id => Some(node_id),
         }
     }
 
     /// returns the first child node, if any
-    pub(crate) fn first_child(&self, node_id: NodeId) -> Option<NodeId> {
+    #[must_use]
+    pub fn first_child(&self, node_id: NodeId) -> Option<NodeId> {
         match self.node(node_id).first_child {
             0 => None,
             node_id => Some(node_id),
@@ -92,12 +96,14 @@ impl<TreeItem> Tree<TreeItem> {
     /// returns the child node with the given index among children nodes
     /// Indices starts with 0, so querying index 0 will return the first child node, if any.
     /// This executes in O(n)
-    pub(crate) fn nth_child(&self, node_id: NodeId, index: usize) -> Option<NodeId> {
+    #[must_use]
+    pub fn nth_child(&self, node_id: NodeId, index: usize) -> Option<NodeId> {
         self.children_iter(node_id).nth(index)
     }
 
     /// returns whether the given node has children or not
-    pub(crate) fn has_children(&self, node_id: NodeId) -> bool {
+    #[must_use]
+    pub fn has_children(&self, node_id: NodeId) -> bool {
         self.node(node_id).first_child != 0
     }
 
@@ -153,7 +159,7 @@ impl<TreeItem: Clone> Clone for Tree<TreeItem> {
 
 /// An iterator through sibling nodes
 #[derive(Debug)]
-pub(crate) struct SiblingIter<'a, TreeItem> {
+pub struct SiblingIter<'a, TreeItem> {
     tree: &'a Tree<TreeItem>,
     current_id: Option<NodeId>,
 }