sequences / collections with units

[erikerlandson]

CoulombVector, CoulombList, etc. It is straightforward to declare Vector[Quantity[...]] but more efficient to abstract out the unit types

[erikerlandson]

for scala 3 collection design and implementations

• https://docs.scala-lang.org/overviews/core/custom-collections.html
• https://docs.scala-lang.org/overviews/core/architecture-of-scala-213-collections.html