bitelist – Split list, in TeX's mouth

The pack­age pro­vides com­mands for “split­ting” a to­ken list at the first oc­cur­rence of an­other (spec­i­fied) to­ken list. I.e., for given to­ken lists s, t re­turn b and the short­est a, such that t = a s b.
The pack­age’s mech­a­nism dif­fers from those of pack­ages pro­vid­ing sim­i­lar fea­tures, in the fol­low­ing ways: – the method uses TeX’s mech­a­nism of read­ing de­lim­ited macro pa­ram­e­ters; – the split­ting macros work by pure ex­pan­sion, with­out as­sign­ments; – the op­er­a­tion is car­ried out in a sin­gle macro call.
A vari­ant of the op­er­a­tion is pro­vided, that re­tains outer braces.