programming. It supports a two-stage process, consisting of macro
interpretation (featuring inside-out evaluation if needed), followed
by a simple and powerful application of stream character filtering.
Its syntax is remindful of \it{TeX}'s, it has dictionary stacks like
\it{PostScript}, and various resemblances to \it{m4} and \it{info}.
It has interfaces to modules making life easy \- counters, references,
arithmetic, multi-dimensional data storage, input/output operations,
regular expressions, and system commands.