search

rust-lang / rustlings

:crab: Small exercises to get you used to reading and writing Rust code!
https://rustlings.cool
MIT License
54.33k stars 10.18k forks source link

View a specific exercise's stdout #262

Closed samaaron closed 4 years ago

samaaron commented 4 years ago

Hi there,

I'm working through rustlings on a Windows machine. It's a wonderful resource - thank-you so much for putting the effort into making it.

One thing I have yet to figure out is how to view the output of the current exercise. Currently I just see if an exercise compiles (and the compile errors if not). However, if an exercise uses println! it would be lovely to be able to see that output somewhere.

Am I doing something wrong or is this something that's yet to be implemented?

rrcobb commented 4 years ago

Hi @samaaron! I think you can get the results of a single exercise (complete with the stdout) using rustlings run <name_of_exercise>.

So, for me, 

$: rustlings run variables3
Number 3
Number 5

✅ Successfully ran exercises/variables/variables3.rs

I don't know if there's a way to get stdout with rustlings verify or with rustlings watch. Maybe getting stdout while watch is incrementally re-running would be a good feature request!

fspy commented 4 years ago

I am also unable to get the output on rustlings run. WSL2, fish/bash.

What can I do that might help diagnose this issue?

fspy commented 4 years ago

To add to my previous comment, I tried running different programs that actually have a main function, and most of them work.

Here are the ones that didn't: as_ref_mut, from_into, errors3, primitive_types1, traits1.

AbdouSeck commented 4 years ago

Hi @fspy, just because a program file has a main in it does not mean that the main function will get invoked. The info.toml file helps the commands look for programs to compile and run or test. If an exercise has a value of test for mode in the info.toml, that means that the program will get compiled and tested only. Its main function does not get invoked.

But you're probably still wondering why then the println! lines in the test cases are not showing? That is a valid question, and one whose answer lies within the rustc --test command that is used by rustlings to run target tests. We can, relatively easily, add the feature to have rustc --test generate display the printed stuff to the standard output (or error).

One solution to your problem may be to add a global flag/option to rustlings called something like --show-output which should force the run, verify and watch commands to output stuff even when the mode of the target exercise is test.

Please, everyone, feel free to chime in and let me know what you think.

Thank you!

Abdou

AbdouSeck commented 4 years ago

@rrcobb @samaaron forgot to mention you in the comment above

sturmenta commented 8 months ago

thanks @AbdouSeck, now I can see my logs using rustlings --nocapture watch