Array-Like mechanism in Pancake

Currently there is no array representation in Pancake. This can be easily worked around using pointer arithmetic, however, without currently having access to multiplication and division this can be cumbersome. Having a native array representation would be a QoL improvement.

The issue proposes a native array representation in Pancake but names no files, tests, or entry points. Start by locating Pancake's representation and semantics code, then determine the required design and tests; done would mean arrays are supported without relying on pointer arithmetic.

Written by the indexing model from the issue text.