Simple Is a Macro Processing Language Element. In other
words, SIMPLE is a macro preprocessor.
It can be described by the following formula: one third of
m4, one third of Scheme, one third of sgml, and one large
third of psychopathic mania. What is a macro preprocessor
exactly? A macro preprocessor is a dedicated programming
language, such as m4 or cpp, that looks partly like a
programming language and partly like ``cat''.