Data::Locations is a virtual file manager which allows you to write and read data (text and binary) to and from virtual files (think of bubbles). Moreover, this manager allows you to (recursively) define "magic" insertion points in these virtual files (bubbles inside other bubbles) which can be filled in (inflated) later (through a "straw", i.e., the object's reference), at any convenient time and in any order you like. Since this software acts purely in memory, there is no slowing down through costly file input/output (i.e., no temporary files).
XML-Lit is a simple program to perform very basic literate programming with any XML-based markup language. It uses James Clark's Expat XML parser to weave (convert to a form suitable for processing) and tangle (extract the source code from) your XML documents. It has only been tested with DocBook at the moment, but there is no reason why it should not work with any arbitrary XML markup.
GNU Source-highlight produces a document with syntax highlighting when given a source file. It handles many languages, e.g., Java, C/C++, Prolog, Perl, PHP3, Python, Flex, HTML, and other formats, e.g., ChangeLog and log files, as source languages and HTML, XHTML, DocBook, ANSI color escapes, LaTeX, and Texinfo as output formats. Input and output formats can be specified with a regular expression-oriented syntax.
Txt2tags converts a text file with minimal markup to HTML, XHTML, SGML, DocBook, LaTeX, Lout, Man page, Creole, Wikipedia, Google Code Wiki, PmWiki, DokuWiki, MoinMoin, MagicPoint, PageMaker, AsciiDoc, or ASCII Art. It is simple and fast and features automatic TOC, macros, filters, include, tools, GUI, CLI, and Web interfaces, translations, and extensive documentation.