The building blocks of YODL's functionality are its em(builtin
functions). Builtin functions exists to manipulate all of YODL's builtin types
(character tables, counters, macros and symbols) and to do basic bookkeeping
and flow-control: it is possible to test values of counters and symbols, to
include other input files, to generate warning and error messages, and to
start child- or subprocesses. Each builtin function is described in a separate
subsection of section lref(BUILTIN)(BUILTIN).
