We want to go towards unsorted configurations, i.e. where no ordering of the orbitals is enforced, and concatenation of two configurations then become an illdefined operation, c.f. c"1s 2s" + c"1s 2p" vs c"1s 2p" + c"1s 2s". If no canonical ordering is enforced, the results would be different between these two operations, which would make the + operator non-commutative. To reduce confusion, the idea is to replace concatenation with + by *. This would also be more in line with Julia's string concatenation.
We want to go towards unsorted configurations, i.e. where no ordering of the orbitals is enforced, and concatenation of two configurations then become an illdefined operation, c.f.
c"1s 2s" + c"1s 2p"vsc"1s 2p" + c"1s 2s". If no canonical ordering is enforced, the results would be different between these two operations, which would make the+operator non-commutative. To reduce confusion, the idea is to replace concatenation with+by*. This would also be more in line with Julia's string concatenation.