braket – Dirac bra-ket and set no­ta­tions

Pro­vides macros to type­set bra-ket no­ta­tion, as well as set spec­i­fiers, with a sin­gle (“|”) or a dou­ble (“||” or (“\|”) ver­ti­cal bar spec­i­fier in be­tween two brack­eted parts. Each macro comes in a fixed-size ver­sion and an ex­pand­ing ver­sion.
If the pack­age finds it­self op­er­at­ing un­der e-tex, it uses the ex­tended prim­i­tive \mid­dle for more re­li­able re­sults