A macro/programming language with stacks
It looks like this:
\def{fib#1}{
\push{fibonacci}
\set{a}{1}
\set{b}{1}
\set{c}{0}
\while{\let{\a <= \1}}{
\setx{c}{\a}
\setx{a}{\let{\a + \b}}
\write{-}{txt}{\c\|}
\setx{b}{\c}
}
\pop{fibonacci}
}
\: need to escape newlines below, lest they ruin the prompt
\write{-}{device}{Enter a number please, then press , \@{\N>\s}}\
\setx{num}{\zinsert{-}}\
\fib{\num}
Zoem has stacks, arithmetic environment, delayed evaluation, inside-out evaluation, and a lot more features to allow abstraction, encapsulation and (lexical) scoping, as well as syntactic sugar to facilitate HTML production.
Built deeply into the zoem language is that it allows distinction between two types of scope; plain scope where text/output is assumed to carry meaning, and device scope, where text/output is assumed to be mark-up. Different filtering mechanisms exist for the two scopes. This facilitates the creation of compact DSL languages that support completely different output formats (e.g. HTML and nroff), such as Portable Unix Documentation.
For more information visit Zoem's homepage.