failed again. just fucking use eyre or color-eyre ffs

src/error.rs

@@ -4,133 +4,320 @@ use std::{
     fmt,
 };
 
-pub trait Context
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, Default)]
+pub struct Context
 {
-    fn line(&self) -> Option<u32>;
-    fn column(&self) -> Option<u32>;
-    fn file(&self) -> Option<&str>;
+    file: Option<&'static str>,
+    line: Option<u32>,
+    column: Option<u32>,
 }
 
-pub trait Reporter
+impl Context
 {
-    type Error: error::Error + ?Sized;
+    pub fn with_all(file: &'static str, line: u32, column: u32) -> Self
+    {
+	Self {
+	    file: Some(file),
+	    line: Some(line),
+	    column: Some(column)
+	}
+    }
+}
 
-    #[inline] fn context(&self) -> Option<&dyn Context>
+impl fmt::Display for Context
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	None
+	if let Some(file) = self.file {
+	    write!(f, "{} ", file)
+	} else {
+	    write!(f, "? ")
+	}?;
+	if let Some(line) = self.line {
+	    write!(f, "{}:", line)
+	} else {
+	    write!(f, "?:")
+	}?;
+	if let Some(column) = self.column {
+	    write!(f, "{}", column)
+	} else {
+	    write!(f, "?")
+	}
     }
-    fn source(&self) -> &Self::Error;
-    
-    fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result;
-    #[inline] fn long_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+}
+
+#[macro_export] macro_rules! context {
+    () => ($crate::error::Context::with_all(file!(), line!(), column!()));
+}
+
+#[derive(Debug)]
+pub struct ContextError<E>(E, Context)
+where E: error::Error;
+
+impl<E> ContextError<E>
+where E: error::Error
+{
+    pub fn with_context(from: E, ctx: Context) -> Self
     {
-	self.short_message(f)
+	Self(from, ctx)
     }
 }
 
-pub struct ShortMessage<R>(R)
-where R: Reporter;
+impl<E> error::Error for ContextError<E>
+where E: error::Error + 'static
+{
+    fn source(&self) -> Option<&(dyn error::Error + 'static)>
+    {
+	Some(&self.0)
+    }
+}
 
-impl<R> fmt::Display for ShortMessage<R>
-where R: Reporter
+impl<E> fmt::Display for ContextError<E>
+where E: error::Error
 {
-    #[inline] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	self.0.short_message(f)
+	write!(f, "{}: {}", self.1, self.0)
     }
 }
 
-pub struct LongMessage<R>(R)
-where R: Reporter;
+#[macro_export] macro_rules! error {
+    ($msg:expr) => {
+	{
+	    pub struct DisplayError<D>(D) where D: fmt::Display;
+	    impl<D> fmt::Debug for DisplayError<D>
+	    where D: fmt::Display
+	    {
+		#[inline] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+		{
+		    write!(f, "{}", std::any::type_name::<Self>())
+		}
+	    }
+	    impl<D> fmt::Display for DisplayError<D>
+	    where D: fmt::Display
+	    {
+		#[inline] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+		{
+		    self.0.fmt(f)
+		}
+	    }
+	    impl<D> error::Error for DisplayError<D>
+	    where D: fmt::Display{}
 
-impl<R> fmt::Display for LongMessage<R>
-where R: Reporter
+		  $crate::error::ContextError::with_context(DisplayError($msg), context!())
+	}
+    };
+    (&fmt:literal $($tt:tt)*) => ($crate::error!(format!($literal $($tt)*)));
+}
+
+pub struct Wrap<E,D>(E,D);
+
+
+impl<E,D> Wrap<E,D>
+where E: error::Error + 'static,
+      D: fmt::Display
 {
-    #[inline] fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    pub fn long_message(&self) -> impl fmt::Display + '_
     {
-	self.0.long_message(f)
+	
+	pub struct LongMessage<'a, E,D>(&'a Wrap<E,D>);
+
+	impl<'a, E,D> fmt::Display for LongMessage<'a,E,D>
+	where E: error::Error + 'static,
+	      D: fmt::Display
+	{
+	    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+	    {
+		use error::Error;
+		for (num, next) in (1..).zip(std::iter::successors(self.0.source(), |e| e.source()))
+		{
+		    writeln!(f, " [{}] -> {}", num, next)?;
+		}
+		Ok(())
+	    }
+	}
+
+	LongMessage(self)
     }
 }
 
-impl<E> Reporter for Box<E>
-where E: error::Error + ?Sized
+impl<E,D> fmt::Display for Wrap<E,D>
+where D: fmt::Display
 {
-    type Error = E;
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	write!(f, "{}", self.1)
+    }
+}
 
-    fn source(&self) -> &Self::Error
+impl<E,D> fmt::Debug for Wrap<E,D>
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	&self
+	write!(f, "{}", std::any::type_name::<Self>())
     }
-    
-    fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+}
+
+
+impl<E,D> error::Error for Wrap<E,D>
+where E: error::Error + 'static,
+      D: fmt::Display
+{
+    fn source(&self) -> Option<&(dyn error::Error + 'static)>
     {
-	write!(f, "{}", &self)
+	Some(&self.0)
     }
 }
 
-impl<'a, R> Reporter for &'a R
-where R: Reporter
+pub trait WrapErrExt<T,E>: Sized
 {
-    type Error = <R as Reporter>::Error;
-    
-    #[inline] fn context(&self) -> Option<&dyn Context>
+    #[inline] fn wrap_err<F,D>(self, val: D) -> Result<T, Wrap<E, D>>
+    where D: fmt::Display
     {
-	(*self).context()
+	self.wrap_err_with(|| val)
     }
-    fn source(&self) -> &Self::Error
+    fn wrap_err_with<F,D>(self, func: F) -> Result<T, Wrap<E, D>>
+    where D: fmt::Display,
+	  F: FnOnce() -> D;
+}
+
+impl<T,E> WrapErrExt<T,E> for Result<T,E>
+{
+    fn wrap_err_with<F,D>(self, func: F) -> Result<T, Wrap<E, D>>
+    where D: fmt::Display,
+	  F: FnOnce() -> D
     {
-	(*self).source()
+	self.map_err(|e| Wrap(e, func()))
     }
+}
+
+
+// We can now define the reporter trait, like last time, and then out own reporter type for `Wrap<E,D>` that prints its long message properly
+
+pub trait Reporter
+{
+    type Error: error::Error + ?Sized;
+
+    #[inline] fn long_message(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	Ok(())
+    }
+    fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result;
+
+    fn source(&self) -> &Self::Error;
+}
+
+impl<E> Reporter for Box<E>
+where E: error::Error + ?Sized
+{
+    type Error = E;
     
     fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	(*self).short_message(f)
+	write!(f, "{}", self)
     }
-    #[inline] fn long_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+
+    fn source(&self) -> &Self::Error
     {
-	(*self).long_message(f)
+	self
     }
 }
 
-pub struct Wrap<E,M>(E, M);
+pub struct WrapReporter<E,D>(Wrap<E,D>);
 
-impl<E,M> Reporter for Wrap<E,M>
-where E: Reporter,
-M: fmt::Display
+impl<E,D> Reporter for WrapReporter<E,D>
+where E: error::Error + 'static,
+      D: fmt::Display
 {
-    type Error = E::Error;
+    type Error = E;
+    
+    fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	write!(f, "{}", self.0)
+    }
 
-    #[inline] fn context(&self) -> Option<&dyn Context>
+    fn long_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	self.0.context()
+	write!(f, "{}", self.0.long_message())
     }
+
     fn source(&self) -> &Self::Error
     {
-	self.0.source()
+	&self.0.0
     }
-    
+}
+
+impl<E,D> From<Wrap<E,D>> for WrapReporter<E,D>
+{
+    fn from(from: Wrap<E,D>) -> Self
+    {
+	Self(from)
+    }
+}
+
+pub struct Report<E>(Box<E>) where E: ?Sized;
+
+impl<E> From<E> for Report<E>
+where E: error::Error 
+{
+    fn from(from: E) -> Self
+    {
+	Self(Box::new(from))
+    }
+}
+impl<E> From<Box<E>> for Report<E>
+where E: error::Error + 'static + ?Sized
+{
+    fn from(from: Box<E>) -> Self
+    {
+	Self(from)
+    }
+}
+
+impl<E> Reporter for Report<E>
+where E: error::Error + ?Sized
+{
+    type Error = E;
+
     fn short_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	write!(f, "{}", self.1)
+	write!(f, "{}", self.0)
     }
-    #[inline] fn long_message(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+
+    fn source(&self) -> &Self::Error
     {
-	write!(f, "{}", self.1)?;
-	self.0.long_message(f) //ehh, also failed
+	&self.0
     }
 }
 
 #[cfg(test)]
-mod tests {
+mod test
+{
     use super::*;
-    fn test() -> Box<dyn error::Error>
+
+    #[test]
+    fn test()
     {
-	Box::new(std::io::Error::new(std::io::ErrorKind::UnexpectedEof, "uhhhhh"))
+	let err: Result<(), _> = Err(error!("hello world"))
+	    .wrap_err_with(|| error!("thing failed"))
+	    .wrap_err_with(|| error!("top level failed again"));
+
+	if let Err(err) = err
+	{
+	    panic!("{}\n\n{}", err, err.long_message());
+	}
     }
+    
     #[test]
-    fn atest()
+    fn report()
     {
-	let bx = test();
-	assert_eq!(format!("{}", LongMessage(&bx)), format!("{}", bx));
+	fn one() -> Result<(), Report<dyn error::Error>>
+	{
+	    let err: Result<(), _> = Err(error!("hello world"))
+		.wrap_err_with(|| error!("thing failed"))
+		.wrap_err_with(|| error!("top level failed again"));
+	    Ok(err?) //failed again. just fucking use eyre
+	}
+
     }
 }