I want in an application with a simple text input, enriched with some marks to include formatting or semantic labeling. I want the syntax as easy as possible and I want to include self-defined labels.
Example: [bold]Stackoverflow[/bold] is a [tag]good[/tag] resource for programmers.
Tables would be needed too.
HTML/XML and LaTeX are mighty enough to allow this, but too complicated. Wiki-Syntax seems simple, but uses another symbol for each markup, has unclear quoting and every Wiki seems to have another syntax. For tables and similar stuff Wiki becomes very complicated.
Exists a language/syntax, that matches my needs or can be slightly changed to do so? Or do I have to invent something myself? In that case, do you have suggestions?
Definitely do NOT invent your own. There are plenty of simple markup languages already, and users HATE learning new ones. Trust me on this!
I would suggest using one of the following:
Make your decision based on your userbase, as well as what tools and parsers are available in your chosen language. For my site, we went with Textile, but I've found that BBCode tends to be the language that most people already know. However, this will vary with different user demographics.