The docgenerator-gem create documents with export feature as LaTeX, HTML, Creole (a common wiki markup, see http://www.wikicreole.org ), conTeXt (only rudimentory), plain text (not very good supported) and

The docgenerator-gem create documents with export feature as LaTeX, HTML, Creole (a common wiki markup, see http://www.wikicreole.org ), conTeXt (only rudimentory), plain text (not very good supported) and Wiki-markup like Wikimedia (no support any longer). This gem extends the docgenerator-gem ...

texlab a toolkit based on erb that for creating documents and doing calculations at the same time. It is capable to output the proper number of significant digits, generate tables and plots using gnuplot. It has a simple DSL.