error: implement an Error instance for ConfigError

src/error.rs

@@ -1,5 +1,6 @@
 //! Errors that can occur while parsing a configuration
 
+use std::error::Error;
 use std::fmt;
 use std::io::Error as IoError;
 use parser::ParseError;
@@ -12,7 +13,9 @@ pub struct ConfigError {
  /// A descriptive message about the error
  pub desc: &'static str,
  /// Error details, if available
- pub detail: Option<String>
+ pub detail: Option<String>,
+
+ err_desc: String
 }
 
 /// Possible error kinds
@@ -26,10 +29,13 @@ pub enum ConfigErrorKind {
 }
 
 fn mk_error<E: fmt::Display>(kind: ConfigErrorKind, desc: &'static str, err: E) -> ConfigError {
+ let err_desc = format!("{:?} {}: {}", kind, desc, err);
  ConfigError {
  kind: kind,
  desc: desc,
- detail: Some(format!("{}", err))
+ detail: Some(format!("{}", err)),
+
+ err_desc: err_desc
  }
 }
 
@@ -42,3 +48,16 @@ pub fn from_io_err(err: IoError) -> ConfigError {
 pub fn from_parse_err(err: ParseError) -> ConfigError {
  mk_error(ConfigErrorKind::ParseError, "Syntax error", err)
 }
+
+impl fmt::Display for ConfigError {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ try!(write!(f, "{}", self.description()));
+ Ok(())
+ }
+}
+
+impl Error for ConfigError {
+ fn description(&self) -> &str {
+ &self.err_desc[..]
+ }
+}