BFFB

BFFB (Brainfuck fucks brains) is a joke language (devised by User:Feuermonster, 2012) whose acronym incidentally is a palindrome. BFFB programs are essentially brainfuck programs with just one little restriction. Due to popular request BFB is an abbreviation for BFFB, incidentally both are palindromic. BFB is the official file extension for BFFB programs.

Restriction

Any given program P consisting of a list of instructions L is a valid prorgam

 iff P ∈ BF where BF is the set of all valid brainfuck programs.
and
 iff L = mirror(L)

Where mirror is a function "mirroring" characters

[ → ]
] → [
> → <
< → >
+ → +
- → -
. → .
, → ,

Example:

[><] | [><] 

Examples

[-]

is a perfectly valid BFFB program.

[>]

is not a valid BFFB program.