It would be nice if the code examples could be edited in-place

[TobiasWehrum]

One thing that I really like about https://doc.rust-lang.org/stable/rust-by-example is that all code can be edited and run right in the browser. While The Book obviously has a different focus, sometimes I feel like it would be nice to make little changes to example code just to see what the result would be. (That applies to almost all code examples, but it's especially true e.g. in listing 7-11 - it would've been great if I could've just uncommented the code and see what happens.)

[TobiasWehrum]

I tried to do that myself to see how hard it would be, and it seems that the main problem is that mdBook doesn't support both hidden code and editable code at the same time. Allowing code to be edited disables the automatic addition of #![allow(unused_variables)] fn main() { } which also means that the code is editable, but doesn't compile. Manually adding those lines with the syntax described here didn't work either - the playpen sections just displayed those lines as they are, with a # in front of them.

By the way, how does the automatic addition of the boilerplate work anyway? I didn't find any mechanism that decides whether to add it or not, nor did I find anything in the mdBook documentation. (edit: Okay, found it. Apparently it's done via some pre-processing magic in rustdoc that is also used in mdBook.)

[carols10cents]

This sounds like there's an issue with mdBook that's blocking this; labeling appropriately.

[carols10cents]

I've decided to close this; if mdbook gets this support, we'll upgrade.