Something inspired me to write a Brainfuck interpreter after reading this so I just put together one in Scheme with a TrollScript compatibility layer. I haven't tested it extensively but it seems to work with everything that I've thrown at it.

https://github.com/Wollw/BrainScript

I wrote it using Guile 1.8.7 and I have no idea if I'm using Guile specific features or not.

edit: Seems it's still a bit broken. The reverse string example in this thread doesn't work for example.

edit2: Well the reverse string example works now. I changed it to read the EOF as equal to 0.