Added todos

Author: simonsan

anti_patterns/catch_panic.md

@@ -37,18 +37,45 @@ unexpected because they are bugs that should not happen. It would not make sense
 to handle an error for QuickSort returning an incorrectly unsorted array, as
 this should not happen.
 
-There are scenarios where using panic::catch_unwind is the correct choice, eg, a
+## Advantages
+
+There are scenarios where using `panic::catch_unwind` is the correct choice, e.g. a
 web server implementation wants to save an unwinding thread in order to send a
 valid response if the route for that request (as in: logic outside of the web server
 implementor's control) is producing a panic.
 
+## Disadvantages
+​
+`panic::catch_unwind` may not catch all panics in Rust. A panic in Rust is not always
+implemented via unwinding, but can be implemented by aborting the process as well.
+`panic::catch_unwind` only catches unwinding panics, not those that abort the process.
+
+Also note that unwinding into Rust code with a foreign exception
+(e.g. a an exception thrown from C++ code) is undefined behavior.
+
+TODO: since Result::unwrap() converts the error to a string, it's harder to distinguish
+between different kinds of errors than if we had matched the result directly.
+
+## Discussion
+
+TODO:
+?-operator to propagate errors
+explain why unwinding is bad
+other disadvantages of panic::catch_unwind
++ "The example could be improved by adding a function and which panics and catching the panic
+in the caller, then matching the Result. Describing the example you could show how by returning
+a Result, the Result-ness of the function is described in the signature."
+
 Expected errors should not result in stack unwinding. Instead, expected errors
 should be handled through the Result and Option types. [The Rust Book's chapter
 on Error Handling](https://doc.rust-lang.org/book/error-handling.html) elaborates further on this.
 
 ## See also
 
 [The Rust Book: Error Handling](https://doc.rust-lang.org/book/error-handling.html)
+
 [Rust 1.9 announcement, which contains a description of this antipattern](http://blog.rust-lang.org/2016/05/26/Rust-1.9.html)
+
 [Result documentation](http://doc.rust-lang.org/std/result/enum.Result.html)
+
 [panic::catch_unwind documentation](https://doc.rust-lang.org/std/panic/fn.catch_unwind.html)