flow::traversible

src/flow.rs

@@ -0,0 +1 @@
+pub mod traversible;

src/flow/traversible.rs

@@ -0,0 +1,164 @@
+use std::rc::Rc;
+
+use crate::func::*;
+
+pub enum Comparison {
+    L,
+    E,
+    R,
+}
+
+fn and(left: bool, right: bool) -> bool {
+    left && right
+}
+
+pub trait Comparator<A> {
+    fn pick_smaller(&self, kl: &A, kr: &A) -> Comparison;
+}
+
+pub type Split<'a, T, A, D> = (
+    Rc<dyn TraversibleBinaryTree<'a, T, A, D>>,
+    Rc<dyn TraversibleBinaryTree<'a, T, A, D>>,
+    Rc<A>,
+);
+
+pub trait TraversibleBinaryNode<'a, T: Monad, A, D: 'a + PartialEq>: 'a {
+    fn split(&self) -> Split<'a, T, A, D>;
+
+    fn to_tree(self: Rc<Self>) -> Rc<dyn TraversibleBinaryTree<'a, T, A, D>>;
+}
+
+pub trait TraversibleBinaryReference<'a, T: Monad, A, D: 'a + PartialEq>: 'a {
+    fn resolve(&self) -> <T as WeakFunctor>::F<'a, Rc<dyn TraversibleBinaryNode<'a, T, A, D>>>;
+
+    /// This should be enough to compare reference for equality.
+    fn data(&self) -> D;
+}
+
+pub trait TraversibleBinaryTree<'a, T: Monad, A, D: 'a + PartialEq>: 'a {
+    fn refer(&self) -> Option<Rc<dyn TraversibleBinaryReference<'a, T, A, D>>>;
+}
+
+pub fn n_contains<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    n_set: Rc<dyn TraversibleBinaryNode<'a, T, A, D>>,
+    key: Rc<A>,
+) -> T::F<'a, bool> {
+    let (t_setl, t_setr, k_set) = n_set.split();
+    match comparator.pick_smaller(key.as_ref(), k_set.as_ref()) {
+        Comparison::L => t_contains(comparator, t_setl, key),
+        Comparison::E => T::pure(true),
+        Comparison::R => t_contains(comparator, t_setr, key),
+    }
+}
+
+pub fn r_contains<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    r_set: Rc<dyn TraversibleBinaryReference<'a, T, A, D>>,
+    key: Rc<A>,
+) -> T::F<'a, bool> {
+    T::bind(r_set.resolve(), |n_set| n_contains(comparator, n_set, key))
+}
+
+pub fn t_contains<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    t_set: Rc<dyn TraversibleBinaryTree<'a, T, A, D>>,
+    key: Rc<A>,
+) -> T::F<'a, bool> {
+    match t_set.refer() {
+        Some(r_set) => r_contains(comparator, r_set, key),
+        None => T::pure(false),
+    }
+}
+
+pub fn n_subset_of_n<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    n_subset: Rc<dyn TraversibleBinaryNode<'a, T, A, D>>,
+    n_superset: Rc<dyn TraversibleBinaryNode<'a, T, A, D>>,
+    k_l: Option<Rc<A>>,
+    k_r: Option<Rc<A>>,
+) -> T::F<'a, bool> {
+    let (t_superl, t_superr, k_super) = n_superset.split();
+    if let Some(ref a_l) = k_l {
+        if let Comparison::R = comparator.pick_smaller(a_l.as_ref(), k_super.as_ref()) {
+            return t_subset_of_t(comparator, n_subset.to_tree(), t_superr, k_l, k_r);
+        }
+    }
+    if let Some(ref a_r) = k_r {
+        if let Comparison::L = comparator.pick_smaller(a_r.as_ref(), k_super.as_ref()) {
+            return t_subset_of_t(comparator, n_subset.to_tree(), t_superl, k_l, k_r);
+        }
+    }
+    let (t_subl, t_subr, k_sub) = n_subset.split();
+    match comparator.pick_smaller(k_sub.as_ref(), k_super.as_ref()) {
+        Comparison::L => T::la2(
+            and,
+            t_contains(comparator, t_superl.clone(), k_sub.clone()),
+            T::la2(
+                and,
+                t_subset_of_t(comparator, t_subl, t_superl, k_l, Some(k_sub.clone())),
+                t_subset_of_t(
+                    comparator,
+                    t_subr,
+                    n_subset.to_tree(),
+                    Some(k_sub.clone()),
+                    k_r,
+                ),
+            ),
+        ),
+        Comparison::E => T::la2(
+            and,
+            t_subset_of_t(comparator, t_subl, t_superl, k_l, Some(k_sub.clone())),
+            t_subset_of_t(comparator, t_subr, t_superr, Some(k_sub.clone()), k_r),
+        ),
+        Comparison::R => T::la2(
+            and,
+            t_contains(comparator, t_superr.clone(), k_sub.clone()),
+            T::la2(
+                and,
+                t_subset_of_t(
+                    comparator,
+                    t_subl,
+                    n_subset.to_tree(),
+                    k_l,
+                    Some(k_sub.clone()),
+                ),
+                t_subset_of_t(comparator, t_subr, t_superr, Some(k_sub.clone()), k_r),
+            ),
+        ),
+    }
+}
+
+pub fn r_subset_of_r<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    r_subset: Rc<dyn TraversibleBinaryReference<'a, T, A, D>>,
+    r_superset: Rc<dyn TraversibleBinaryReference<'a, T, A, D>>,
+    k_l: Option<Rc<A>>,
+    k_r: Option<Rc<A>>,
+) -> T::F<'a, bool> {
+    T::join(T::la2(
+        move |n_subset, n_superset| n_subset_of_n(comparator, n_subset, n_superset, k_l, k_r),
+        r_subset.resolve(),
+        r_superset.resolve(),
+    ))
+}
+
+pub fn t_subset_of_t<'a, T: Monad, A, D: 'a + PartialEq>(
+    comparator: &'a dyn Comparator<A>,
+    t_subset: Rc<dyn TraversibleBinaryTree<'a, T, A, D>>,
+    t_superset: Rc<dyn TraversibleBinaryTree<'a, T, A, D>>,
+    k_l: Option<Rc<A>>,
+    k_r: Option<Rc<A>>,
+) -> T::F<'a, bool> {
+    match (t_subset.refer(), t_superset.refer()) {
+        (None, _) => T::pure(true),
+        (Some(_), None) => T::pure(false),
+        (Some(r_subset), Some(r_superset)) => {
+            if r_subset.data() == r_superset.data() {
+                T::pure(true)
+            } else {
+                r_subset_of_r(comparator, r_subset, r_superset, k_l, k_r)
+            }
+        }
+    }
+}

src/lib.rs

@@ -1,4 +1,5 @@
 pub mod core;
+pub mod flow;
 pub mod func;
 pub mod std;
 #[cfg(test)]

src/std/local_origin.rs

@@ -19,7 +19,7 @@ impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> Point<'a, Ctx, A> {
         Self::from_fields(point, Rc::new(origin))
     }
 
-    fn from_mentionable(mentionable: A) -> Self {
+    fn from_mentionable(mentionable: Rc<A>) -> Self {
         Self::from_values(
             Ctx::hash(&Self::prepare_bytes_for_hashing(&mentionable)),
             LocalOrigin::from(mentionable),
@@ -41,14 +41,20 @@ impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> Origin<'a, Ctx> for LocalOr
     }
 }
 
-impl<A> From<A> for LocalOrigin<A> {
-    fn from(value: A) -> Self {
-        LocalOrigin(value.into())
+impl<A> From<Rc<A>> for LocalOrigin<A> {
+    fn from(value: Rc<A>) -> Self {
+        LocalOrigin(value)
+    }
+}
+
+impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> From<Rc<A>> for Point<'a, Ctx, A> {
+    fn from(value: Rc<A>) -> Self {
+        Self::from_mentionable(value)
     }
 }
 
 impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> From<A> for Point<'a, Ctx, A> {
     fn from(value: A) -> Self {
-        Self::from_mentionable(value)
+        Self::from_mentionable(value.into())
     }
 }

src/std/nullable.rs

@@ -78,15 +78,21 @@ impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> Nullable<'a, Ctx, Nullable<
     /// Reduce [Nullable] nesting.
     pub fn join(&self) -> Resolution<'a, Ctx, Nullable<'a, Ctx, A>> {
         match self {
-            Nullable::Null(nullable_factory) => {
+            Self::Null(nullable_factory) => {
                 let NullableFactory { factory } = nullable_factory;
                 Ctx::T::pure(Ok(Rc::new(Nullable::Null(factory.clone()))))
             }
-            Nullable::NotNull(point) => point.resolve(),
+            Self::NotNull(point) => point.resolve(),
         }
     }
 }
 
+impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> Nullable<'a, Ctx, A> {
+    fn from_mentionable(mentionable: Rc<A>) -> Self {
+        Self::NotNull(mentionable.into())
+    }
+}
+
 impl<F> NullableFactory<F> {
     pub fn new(factory: F) -> Self {
         Self { factory }
@@ -105,3 +111,15 @@ impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> Clone for Nullable<'a, Ctx,
 impl<F> AlwaysConstSize for NullableFactory<F> {
     const _SIZE: usize = HASH_SIZE;
 }
+
+impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> From<Rc<A>> for Nullable<'a, Ctx, A> {
+    fn from(value: Rc<A>) -> Self {
+        Self::from_mentionable(value)
+    }
+}
+
+impl<'a, Ctx: 'a + Context, A: Mentionable<'a, Ctx>> From<A> for Nullable<'a, Ctx, A> {
+    fn from(value: A) -> Self {
+        Self::from_mentionable(value.into())
+    }
+}