Implement std::error::Error (#71)

Author: andber1

.github/workflows/rust.yml

@@ -47,7 +47,7 @@ jobs:
       - name: Install thumbv7em-none-eabihf target
         run: rustup target add thumbv7em-none-eabihf
 
-      - name: Run cargo build
+      - name: Run cargo build (no_std)
         uses: actions-rs/cargo@v1
         env:
           RUSTFLAGS: -D warnings
@@ -61,7 +61,7 @@ jobs:
           RUSTFLAGS: -D warnings
         with:
           command: build
-          args: --all-features --release --target thumbv7em-none-eabihf
+          args: --all-features --release
 
   test:
     name: Test Suite

Cargo.toml

@@ -25,3 +25,4 @@ features = ["vector"]
 [features]
 default = ["orientation"]
 orientation = []
+std = []

src/error.rs

@@ -100,3 +100,25 @@ where
         Self::new_with_cause(ErrorKind::Bus, cause)
     }
 }
+
+#[cfg(feature = "std")]
+impl<E> std::error::Error for Error<E>
+where
+    E: Debug + std::error::Error + 'static,
+{
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        self.cause
+            .as_ref()
+            .map(|cause| cause as &(dyn std::error::Error + 'static))
+    }
+}
+
+#[cfg(feature = "std")]
+impl<E> Display for Error<E>
+where
+    E: Debug,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", self.kind)
+    }
+}

src/lib.rs

@@ -39,6 +39,9 @@
 #![forbid(unsafe_code)]
 #![warn(missing_docs, rust_2018_idioms, unused_qualifications)]
 
+#[cfg(feature = "std")]
+extern crate std;
+
 mod accelerometer;
 pub mod error;
 #[cfg(feature = "orientation")]