esolangs | Collection of interpreters for esoteric programming | Interpreter library

To apply fillvalues to uneven lists, use the itertools.zip_longest function.

This program parses 332682811 as a little-endian base-9 integer and prints it in base-10.

Befunge interprets instructions on a 2D grid (or torus, depending on version), with an instruction pointer that can move freely in two dimensions. This program is a one-liner, so the instruction pointer only moves forward and backward.

9332682811 pushes those digits individually onto Befunge's value stack, and then the following instructions perform a simple loop. In a normal iteration of the loop, things look like this:

This sounds a lot like you're remembering Whirl.

probably circa 2005

Plausible, Whirl was created in 2004.

two separate 'instruction wheels'

There's an Operations Ring and a Math Ring.

a brainfuck-like array with pointer as memory

It has "An 'infinite' supply of data memory" (which is used like a BF tape). It also has a register for each ring though.

The instructions were 'rotate the given wheel' and 'execute instruction and switch wheels

Sort of, the second instruction is a bit more complicated and is really two different instructions. 0 reverses the direction of the current ring. 00 does the same but also executes the current command and switches the rings.

The only instruction common to both wheels was NOOP.

Sort of. Both wheels also have a Load and Store command, but they work with different registers.

I think the language was turing-complete (possibly by a trivial reduction to BF).

Indeed. I can't find an actual reduction anywhere, but we can easily see that <> can be implemented with DAdd, [] with PAdd and If and +- with Add and Neg (in all cases with Load and Store thrown in for good measure).

Here's a diagram for how the memory movement commands work:

The memory pointer (MP) has a position (which is an edge of the memory grid) and an orientation along that edge. In the diagram, the initial position of the MP is marked with the red arrow, so it currently points north.

The MP movement commands are always relative to the current position and orientation of the MP. I've annotated the four adjacent edges based on which command gets you there. So { moves the MP forward and to left, and ' moves it backward and to the right, for example.

To figure out its new orientation, you can think of this movement as rotating the MP by 60 degrees about one of the adjacent hexagons. So depending on the chosen command, the MP would point in the following directions for the above diagram: