Fix 1375: Infinite loop in interpreter

[kcsongor]

The code example in #1375 caused the REPL to get in an infinite loop, and eventually terminate in an out of memory error.

The cause of this was the way the / character was handled, or more precisely, the character following a /. Instead of peeking the next character, it was polled, and in case of a no match, was put back using the lazy stream cons, which doesn't play nicely with expressions of the form stream = n #:: stream (or I should say it can be surprising).

[smarter]

/rebuild

[smarter]

@kcsongor: Thanks for your contribution! Before we can accept your patch, you'll need to sign the Scala CLA at http://www.lightbend.com/contribute/cla/scala

[kcsongor]

@smarter: thanks, I've signed it

[felixmulder]

Since there is no immutable StringBuilder, this distinction feels slightly redundant.

[felixmulder]

Otherwise LGTM

[kcsongor]

I've made the suggested changes, not sure if/how I can squash the commits in the github web editor

[smarter]

You can't do it online, but you can do it locally with git and then push-force (git push -f): https://ariejan.net/2011/07/05/git-squash-your-latests-commits-into-one/

[kcsongor]

I wasn't near my own computer at the time, and I was hoping that I can squash them quickly, but anyway, it should be good now

[felixmulder]

Great, thanks for the contribution :)