Bracketext
Bracketext is a word processing system consisting of macro delimiters to be placed in a text and a stack-based programming language make it possible to define macro. The text is then evaluated by the software which generates a text as a result (in HTML for example). This allows you to create HTML pages from of a plain text.
Here is an example of a text file using current macros:
[doc]
[title|1]EXAMPLE[/title]
[p]
This is an example of text using [b] Bracketext [/b]
[/p]
[/doc]
For now, no executable file is available, but you can find the source of Bracketext on GitHub.
If you want to write your own macros, you'll need to program them in JavaScript. You can take an example from those in the macros.txt file. For now, the macros I've set are modeled on the bbcode.