ktv-texdata – Extract subsets of documents

The pack­age de­fines an ex­er­cice en­vi­ron­ment which num­bers ev­ery ex­er­cise, and a com­mand \get to ex­tract a col­lec­tion whose ar­gu­ment is a comma-sep­a­rated set of ex­er­cise in­dex num­bers.
While the pack­age was de­signed for teach­ers con­struct­ing ta­bles of ex­er­cises, it plainly has more gen­eral ap­pli­ca­tion.