This package provides macros for measuring alphabet lengths
(i.e. the length occupied by the characters "abcd...xyz"), em-
widths and ex-heights, which may help in making typesetting
decisions. The package is compatible with pdfLaTeX, LuaLaTeX,
and XeLaTeX, and will accept font family switches defined via
the fontspec package. The plan is that future versions shall be
able to provide even more diagnostic tools, and some LuaTeX-
specific special commands, too. The package relies on the
following other LaTeX packages: expl3, array, booktabs, and
siunitx.