crossterm | Cross platform terminal library rust | Command Line Interface library

The behaviour of the panic! macro changed a bit with the Rust 2021 edition, to make it more consistent with other format family macros. An entire chapter of the migration guide is dedicated to this.

The fix, and the link with the detailed information is also indicated in the error message you get:

To my knowledge, there's neither a crate to do this parsing from a string to a crossterm key, nor even a normalized format.

You'll also have to deal with specifics of both Crossterm and your application. It especially depends on how you want to use the key. For example, if you want to parameterize a mapping from an event to an action, you may want to transform the key a little so that it matches what Crossterm may produce.

You might use a function like this one:

In main:

I am going to answer my own question because I went through a lot of discovery here and I am sure other will find it useful.

BTW - the original question got derailed in the comments section explaining why my c++ equivalent (without flush) worked / didnt work / shouldnt work / might work. Lets ignore that - I added flush.

Firstly Debuggers

vscode and Vs2019 do stuff with stdout in order to try to be helpful. Most of the time it is helpful but not in this case

vscode steals stdout to make it appear in the terminal window. Normally this would be directed to a console window. It also imposes its own buffering regardless of what you do with flushing etc.

The real end for my rust code is a c# gui application calling the rust code as a cdylib. Originally this dll was written in c++. When running a GUI app vs2019 also steals stdout (not the case for console apps, nothing to do with my mini c++ code above) so that it can display it the 'output' window.

Both these behaviors disappear if the app is run outside the debugger of course. But that makes debugging tough.

This of course confused a lot of my investigation because I was not seeing output in various cases because I was looking in the wrong place.

Solution 1

The original code in my question actually works fine if you run it via cargo run from a console window. Excellent. vscode buffers it all up if ran from inside it - so dont do that.

Problem 2, no console window

Windows gui app launch 'knows' that this program doesnt need a console window so stdout is piped to a bitbucket. I had the same issue in the c# -> c++ version. The secret here is to create a console window and reattach stdout to it.

solution 2

Reaches for winapi crate.