diff --git a/src/libstd/error.rs b/src/libstd/error.rs index 2a2d41112ffae..1459420cdc00c 100644 --- a/src/libstd/error.rs +++ b/src/libstd/error.rs @@ -66,10 +66,80 @@ pub trait Error: Debug + Display + Reflect { /// The description should not contain newlines or sentence-ending /// punctuation, to facilitate embedding in larger user-facing /// strings. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// + /// match "xc".parse::() { + /// Err(e) => { + /// println!("Error: {}", e.description()); + /// } + /// _ => println!("No error"), + /// } + /// ``` #[stable(feature = "rust1", since = "1.0.0")] fn description(&self) -> &str; /// The lower-level cause of this error, if any. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::fmt; + /// + /// #[derive(Debug)] + /// struct SuperError { + /// side: SuperErrorSideKick, + /// } + /// + /// impl fmt::Display for SuperError { + /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + /// write!(f, "SuperError is here!") + /// } + /// } + /// + /// impl Error for SuperError { + /// fn description(&self) -> &str { + /// "I'm the superhero of errors!" + /// } + /// + /// fn cause(&self) -> Option<&Error> { + /// Some(&self.side) + /// } + /// } + /// + /// #[derive(Debug)] + /// struct SuperErrorSideKick; + /// + /// impl fmt::Display for SuperErrorSideKick { + /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + /// write!(f, "SuperErrorSideKick is here!") + /// } + /// } + /// + /// impl Error for SuperErrorSideKick { + /// fn description(&self) -> &str { + /// "I'm SuperError side kick!" + /// } + /// } + /// + /// fn get_super_error() -> Result<(), SuperError> { + /// Err(SuperError { side: SuperErrorSideKick }) + /// } + /// + /// fn main() { + /// match get_super_error() { + /// Err(e) => { + /// println!("Error: {}", e.description()); + /// println!("Caused by: {}", e.cause().unwrap()); + /// } + /// _ => println!("No error"), + /// } + /// } + /// ``` #[stable(feature = "rust1", since = "1.0.0")] fn cause(&self) -> Option<&Error> { None }