diff --git a/src/rstd/collections/tree.rs b/src/rstd/collections/tree.rs
index 61c1826..f0bdb14 100644
--- a/src/rstd/collections/tree.rs
+++ b/src/rstd/collections/tree.rs
@@ -1,3 +1,5 @@
+pub mod context;
+
 use std::{error::Error, fmt::Display, rc::Rc};
 
 use crate::{
@@ -190,3 +192,22 @@ impl<'a, Ctx: Context<'a>, F: Factory<'a, Ctx>> Factory<'a, Ctx> for TreeFactory
         Ok(mentionable)
     }
 }
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone> Clone for Node<'a, Ctx, A> {
+    fn clone(&self) -> Self {
+        Self {
+            l: self.l.clone(),
+            r: self.r.clone(),
+            key: self.key.clone(),
+        }
+    }
+}
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone> Clone for Tree<'a, Ctx, A> {
+    fn clone(&self) -> Self {
+        Self {
+            node: self.node.clone(),
+            height: self.height,
+        }
+    }
+}
diff --git a/src/rstd/collections/tree/context.rs b/src/rstd/collections/tree/context.rs
new file mode 100644
index 0000000..1e109fa
--- /dev/null
+++ b/src/rstd/collections/tree/context.rs
@@ -0,0 +1,75 @@
+use std::{marker::PhantomData, rc::Rc};
+
+use crate::{
+    flow::{binary::*, comparator::*},
+    func::context::*,
+    rcore::*,
+    rstd::fallible::*,
+};
+
+use super::*;
+
+struct TreeContext<C, T>(Rc<C>, PhantomData<T>);
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>, E: 'a>
+    TreeContext<C, (Ctx, A, E)>
+{
+    fn new(comparator: Rc<C>) -> Self {
+        Self(comparator, PhantomData)
+    }
+}
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>, E: 'a> Clone
+    for TreeContext<C, (Ctx, A, E)>
+{
+    fn clone(&self) -> Self {
+        Self::new(self.0.clone())
+    }
+}
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>, E: 'a>
+    FunctorContext<'a> for TreeContext<C, (Ctx, A, E)>
+{
+    type T = FallibleMonad<'a, Ctx, Result<ResolutionFailure<'a, Ctx, Node<'a, Ctx, A>>, E>>;
+}
+
+impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx> + Clone, C: 'a + Comparator<A>, E: 'a>
+    BinaryTrees<'a> for TreeContext<C, (Ctx, A, E)>
+{
+    type Node = Node<'a, Ctx, A>;
+
+    type Reference = Point<'a, Ctx, Self::Node>;
+
+    type Tree = Tree<'a, Ctx, A>;
+
+    type Key = A;
+
+    type Comparator = C;
+
+    type _Tm = Self::T;
+
+    fn comparator(&self) -> &Self::Comparator {
+        &self.0
+    }
+
+    fn split(&self, node: &Self::Node) -> crate::flow::binary::Split<'a, Self> {
+        (node.l.clone(), node.r.clone(), node.key.clone())
+    }
+
+    fn resolve(
+        &self,
+        reference: &Self::Reference,
+    ) -> crate::flow::binary::BTWrap<'a, Self, Self::Node> {
+        Ctx::stuff(Ctx::fmap(reference.resolve(), |resolved| {
+            resolved.map(|rc| rc.as_ref().clone()).map_err(Ok)
+        }))
+    }
+
+    fn equal(&self, rl: &Self::Reference, rr: &Self::Reference) -> bool {
+        rl == rr
+    }
+
+    fn refer(&self, tree: &Self::Tree) -> Option<Self::Reference> {
+        tree.node.as_ref().cloned()
+    }
+}
diff --git a/src/rstd/nullable.rs b/src/rstd/nullable.rs
index 78257d3..2012e9f 100644
--- a/src/rstd/nullable.rs
+++ b/src/rstd/nullable.rs
@@ -96,6 +96,13 @@ impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx>> Nullable<'a, Ctx, A> {
     fn from_mentionable(mentionable: Rc<A>) -> Self {
         Self::NotNull(mentionable.into())
     }
+
+    pub fn as_ref(&self) -> Option<&Point<'a, Ctx, A>> {
+        match self {
+            Nullable::Null(_) => None,
+            Nullable::NotNull(point) => Some(point),
+        }
+    }
 }
 
 impl<F> NullableFactory<F> {