This is useful, and Ruby also has this. Give us some time to review it with @waj, and also check #1641, and we'll probably merge it.

@jreinert Do you want to rebase this? Then we'll merge it.

@asterite done!

#triage
@jreinert It seems like there's a need for a syntax update, as pointed out by @asterite .
A rebase against master is always a good idea, as this will trigger the most current CI build/test suite.

all done

@jreinert Thanks for the rebase. As you can see, the build fails on undefined constant StringIO.

In crystal 0.9.0, StringIO was renamed to MemoryIO - could you please rename the specs and docs?

Merged in 5fa22e6 . Thank you!