Wanted: a #RustLang tool with 4 panes:
- desired generated code
- an in progress proc-macro being written
- input #Rust code where the proc-macro is being applied
- a live updating view of the actual generated code with diff annotations against what was desired
If you want to go fancier, tie things in the output to the input and provide suggestions on where things are missing pre-expansion for the output to march the expectation. I feel like 90% of this can be accomplished today with tmux+a file watcher+direct rustc invocations using -Zunpretty=expanded, but it'd be lovely to have an actual tool for this.