in­ter­preter – Trans­late in­put files on the fly

The pack­age pre­pro­cesses in­put files to a Lua(La)TeX run, on the fly.
The user de­fines Lua reg­u­lar ex­pres­sions to search for pat­terns and mod­ify in­put lines (or en­tire para­graphs) ac­cord­ingly, be­fore TeX reads the ma­te­rial. In this way, doc­u­ments may be pre­pared in a non-TeX lan­guage (e.g., some lightweight markup lan­guage) and turned into ‘proper’ TeX for pro­cess­ing.
The source of the doc­u­men­ta­tion is typed in such a lightweight lan­guage and is thus eas­ily read­able in a text ed­i­tor (the PDF file is also avail­able, of course); the trans­for­ma­tion to TeX syn­tax via In­ter­preter's func­tions is ex­plained in the doc­u­men­ta­tion it­self.
In­ter­preter is im­ple­mented us­ing the au­thor’s gates (lua ver­sion), and works for plain TeX and LaTeX, but not ConTeXt.