tab­bing­box – Save a tab­bing en­vi­ron­ment in a box

De­fines an en­vi­ron­ment tab­bing­box, which puts tab­bing en­vi­ron­ment com­mands in a box. This is one way of get­ting a bunch of lines into a box, where the width of the box is that of the widest line.
The macros use the may­be­load and re­de­fine macro bun­dles.