Investigate position-based instancing

[Shfty]

• Theory is to partition space into a set of cells using an infinitely repeatable operator (ex. modulus), assign them some unique identifier, and use that identifier to affect future calculations
  • ex. Use to conditionally pick fields by instance index, modulate position or other parameters, etc.
  • Would be ideal to make repeatable operator compositional
  • Flexible and good performance profile, with the caveat that instances are bounded to their cell and cannot overlap
  • Similar to Inigo Quilez' repetition operators, with the addition of instance index (possibly multidimensional)
  • Handy for ex. text, since a regular horizontal layout can be encoded via modulus, and instance ID can be used to index into a list of fields that are converted from an &str at codegen time

[Shfty]

Done: Opted to implement as Repeat w/vector IDs instead of a generalized compositional setup for now; easy enough to introduce new context members to account for operator-specific IDing.