Merge pull request #133 from RalfJung/printing

Print backtraces more like libstd does

src/capture.rs

@@ -10,6 +10,9 @@ use types::c_void;
 ///
 /// This structure can be used to capture a backtrace at various points in a
 /// program and later used to inspect what the backtrace was at that time.
+///
+/// `Backtrace` supports pretty-printing of backtraces by implementing
+/// `Display` and `Debug` (which do the same thing).
 #[derive(Clone)]
 #[cfg_attr(feature = "serialize-rustc", derive(RustcDecodable, RustcEncodable))]
 #[cfg_attr(feature = "serialize-serde", derive(Deserialize, Serialize))]
@@ -230,32 +233,37 @@ impl fmt::Debug for Backtrace {
 
         for (idx, frame) in iter.enumerate() {
             let ip = frame.ip();
-            write!(fmt, "\n{:4}: {:2$?}", idx, ip, hex_width)?;
+            write!(fmt, "\n{:4}: ", idx)?;
 
             let symbols = match frame.symbols {
                 Some(ref s) => s,
                 None => {
-                    write!(fmt, " - <unresolved>")?;
+                    write!(fmt, "<unresolved> ({:?})", ip)?;
                     continue
                 }
             };
             if symbols.len() == 0 {
-                write!(fmt, " - <no info>")?;
+                write!(fmt, "<no info> ({:?})", ip)?;
+                continue;
             }
 
             for (idx, symbol) in symbols.iter().enumerate() {
                 if idx != 0 {
-                    write!(fmt, "\n      {:1$}", "", hex_width)?;
+                    write!(fmt, "\n      ")?;
                 }
 
                 if let Some(name) = symbol.name() {
-                    write!(fmt, " - {}", name)?;
+                    write!(fmt, "{}", name)?;
                 } else {
-                    write!(fmt, " - <unknown>")?;
+                    write!(fmt, "<unknown>")?;
+                }
+
+                if idx == 0 {
+                    write!(fmt, " ({:?})", ip)?;
                 }
 
                 if let (Some(file), Some(line)) = (symbol.filename(), symbol.lineno()) {
-                    write!(fmt, "\n      {:3$}at {}:{}", "", file.display(), line, hex_width)?;
+                    write!(fmt, "\n             at {}:{}", file.display(), line)?;
                 }
             }
         }
@@ -264,6 +272,12 @@ impl fmt::Debug for Backtrace {
     }
 }
 
+impl fmt::Display for Backtrace {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self, fmt)
+    }
+}
+
 impl Default for Backtrace {
     fn default() -> Backtrace {
         Backtrace::new()