From 634614a2a152835742078120b5c102c759f657e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ja=C5=ADhien=20Piatlicki?=
 <jauhien.piatlicki@asynchronics.com>
Date: Thu, 31 Oct 2024 14:11:25 +0100
Subject: [PATCH 1/3] Add observable states utility

---
 Cargo.toml                          |  2 +-
 asynchronix-util/Cargo.toml         |  7 +++
 asynchronix-util/src/lib.rs         |  1 +
 asynchronix-util/src/observables.rs | 85 +++++++++++++++++++++++++++++
 asynchronix/Cargo.toml              |  2 +
 5 files changed, 96 insertions(+), 1 deletion(-)
 create mode 100644 asynchronix-util/Cargo.toml
 create mode 100644 asynchronix-util/src/lib.rs
 create mode 100644 asynchronix-util/src/observables.rs

diff --git a/Cargo.toml b/Cargo.toml
index c24bd10..6894a12 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,3 +1,3 @@
 [workspace]
-members = ["asynchronix"]
+members = ["asynchronix", "asynchronix-util"]
 resolver = "2"
diff --git a/asynchronix-util/Cargo.toml b/asynchronix-util/Cargo.toml
new file mode 100644
index 0000000..af5f158
--- /dev/null
+++ b/asynchronix-util/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "asynchronix-util"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+asynchronix = {version = "0.2.2", path = "../asynchronix"}
diff --git a/asynchronix-util/src/lib.rs b/asynchronix-util/src/lib.rs
new file mode 100644
index 0000000..4010ef7
--- /dev/null
+++ b/asynchronix-util/src/lib.rs
@@ -0,0 +1 @@
+pub mod observables;
diff --git a/asynchronix-util/src/observables.rs b/asynchronix-util/src/observables.rs
new file mode 100644
index 0000000..1adefa0
--- /dev/null
+++ b/asynchronix-util/src/observables.rs
@@ -0,0 +1,85 @@
+use std::ops::Deref;
+
+use asynchronix::ports::Output;
+
+/// Observability trait.
+pub trait Observable<T> {
+    /// Observe the value.
+    fn observe(&self) -> T;
+}
+
+impl<T> Observable<T> for T
+where
+    T: Clone,
+{
+    fn observe(&self) -> Self {
+        self.clone()
+    }
+}
+
+/// Observable state.
+///
+/// This struct incapsulates state. Every state change is propagated to the
+/// output.
+#[derive(Debug)]
+pub struct ObservableState<S, T>
+where
+    S: Observable<T> + Default,
+    T: Clone + Send + 'static,
+{
+    /// State.
+    state: S,
+
+    /// Output used for observation.
+    out: Output<T>,
+}
+
+impl<S, T> ObservableState<S, T>
+where
+    S: Observable<T> + Default,
+    T: Clone + Send + 'static,
+{
+    /// New default state.
+    pub fn new(out: Output<T>) -> Self {
+        Self {
+            state: S::default(),
+            out,
+        }
+    }
+
+    /// Get state.
+    pub fn get(&self) -> &S {
+        &self.state
+    }
+
+    /// Set state.
+    pub async fn set(&mut self, value: S) {
+        self.state = value;
+        self.out.send(self.state.observe()).await;
+    }
+
+    /// Modify state using mutable reference.
+    pub async fn modify<F, R>(&mut self, f: F) -> R
+    where
+        F: FnOnce(&mut S) -> R,
+    {
+        let r = f(&mut self.state);
+        self.out.send(self.state.observe()).await;
+        r
+    }
+}
+
+impl<S, T> Deref for ObservableState<S, T>
+where
+    S: Observable<T> + Default,
+    T: Clone + Send + 'static,
+{
+    type Target = S;
+
+    fn deref(&self) -> &S {
+        &self.state
+    }
+}
+
+/// Observable value.
+pub type ObservableValue<T> = ObservableState<T, T>;
diff --git a/asynchronix/Cargo.toml b/asynchronix/Cargo.toml
index 5f30507..a5eee42 100644
--- a/asynchronix/Cargo.toml
+++ b/asynchronix/Cargo.toml
@@ -4,6 +4,8 @@ name = "asynchronix"
 # - Update crate version in this Cargo.toml
 # - Update crate version in README.md
 # - Update crate version in the lib.rs documentation of feature flags
+# - Update dependency in sibling crates
+# - Remove path dependencies
 # - Update CHANGELOG.md
 # - Update if necessary copyright notice in LICENSE-MIT
 # - Create a "vX.Y.Z" git tag

From 087f3c84cc17048e6448d1f6560ec4333a873cd0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ja=C5=ADhien=20Piatlicki?=
 <jauhien.piatlicki@asynchronics.com>
Date: Thu, 31 Oct 2024 14:51:33 +0100
Subject: [PATCH 2/3] Add README to asynchronix-util

---
 asynchronix-util/README.md | 3 +++
 1 file changed, 3 insertions(+)
 create mode 100644 asynchronix-util/README.md

diff --git a/asynchronix-util/README.md b/asynchronix-util/README.md
new file mode 100644
index 0000000..4bdbc8d
--- /dev/null
+++ b/asynchronix-util/README.md
@@ -0,0 +1,3 @@
+# Utilities for model-building
+
+TODO: add documentation

From 0732a7ef54db62194adece5eb6e9efb07b923257 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ja=C5=ADhien=20Piatlicki?=
 <jauhien.piatlicki@asynchronics.com>
Date: Thu, 31 Oct 2024 15:59:35 +0100
Subject: [PATCH 3/3] Changes after review

---
 asynchronix-util/src/observables.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/asynchronix-util/src/observables.rs b/asynchronix-util/src/observables.rs
index 1adefa0..45bb28a 100644
--- a/asynchronix-util/src/observables.rs
+++ b/asynchronix-util/src/observables.rs
@@ -19,7 +19,7 @@ where
 
 /// Observable state.
 ///
-/// This struct incapsulates state. Every state change is propagated to the
+/// This object encapsulates state. Every state change is propagated to the
 /// output.
 #[derive(Debug)]
 pub struct ObservableState<S, T>
@@ -67,6 +67,11 @@ where
         self.out.send(self.state.observe()).await;
         r
     }
+
+    /// Propagate value.
+    pub async fn propagate(&mut self) {
+        self.out.send(self.state.observe()).await;
+    }
 }
 
 impl<S, T> Deref for ObservableState<S, T>