Poll changes

src/error.rs

@@ -1,4 +1,6 @@
-/// An error that it is likely impossible to recover. This error should only be created in
+use crate::transducer::InvalidValue;
+
+/// An error that it is likely impossible to recover from. This error should only be created in
 /// situations where attempts to recover have already been attempted and have failed. Error handling
 /// should consist of attempting to alert another system for maintenance and attempting to shut down
 /// any systems that depend on the correct functionality of the component having errors.
@@ -9,4 +11,31 @@
 pub enum CriticalError {
     /// Critical communication failed and retries are either impossible or also failed.
     Communication,
+    InvalidValue(InvalidValue),
+}
+
+impl CriticalError {
+    pub fn emergency_procedure(self, procedure: impl FnOnce(CriticalError) -> !) -> ! {
+        procedure(self);
+    }
+}
+
+/// [Result] where error type is [CriticalError].
+pub trait CriticalErrResult: Copy {
+    type Value: Copy;
+
+    /// Execute emergency procedure in the event of a critical, the emergency procedure cannot
+    /// return. It should usually terminate the program, potentially rebooting the device in some sort of recovery mode.
+    fn err_emproc(self, procedure: impl FnOnce(CriticalError) -> !) -> Self::Value;
+}
+
+impl<T: Copy> CriticalErrResult for Result<T, CriticalError> {
+    type Value = T;
+
+    fn err_emproc(self, procedure: impl FnOnce(CriticalError) -> !) -> Self::Value {
+        match self {
+            Ok(val) => val,
+            Err(error) => error.emergency_procedure(procedure),
+        }
+    }
 }

src/lib.rs

@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(async_fn_in_trait)]
+#![feature(async_fn_in_trait, never_type)]
 
 pub mod transducer;
 pub mod cell;

src/transducer/input.rs

@@ -1,7 +1,6 @@
-use crate::CriticalError;
-
 pub trait Poll {
     type Value: Copy;
+    type Error: Copy;
 
-    async fn poll(&self) -> Result<Self::Value, CriticalError>;
+    async fn poll(&self) -> Result<Self::Value, Self::Error>;
 }

src/transducer/mod.rs

@@ -51,3 +51,10 @@ impl<T: Copy> From<Cell<T>> for State<T> {
         State::new(state_cell)
     }
 }
+
+// ---------------------------------------------------------------------------------------------------------------------
+// ----- Error ------------------------
+// ---------------------------------------------------------------------------------------------------------------------
+/// Indicates the transducer value is statically known to be impossible.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub struct InvalidValue;

src/transducer/output.rs

@@ -1,9 +1,8 @@
+use crate::transducer::InvalidValue;
+
 pub trait Output {
     type Value: Copy;
 
     //TODO: Should this be maybe async?
-    fn output(&mut self, setting: Self::Value) -> Result<(), InvalidOutputSetting>;
+    fn output(&mut self, setting: Self::Value) -> Result<(), InvalidValue>;
 }
-
-/// Indicates the setting given for an [Output] is statically known to be an impossible setting to achieve.
-pub struct InvalidOutputSetting;