Question

I need to implement something similar to wikilinks on my site. The user is entering plain text and will enter [[asdf]] wherever there is an internal link. Only the first five examples are really applicable in the implementation I need.

Would you use regex, what expression would do this? Is there a library out there somewhere that already does this in C#?

Answer 1

On the pure regexp side, the expression would rather be:

\[\[([^\]\|\r\n]+?)\|([^\]\|\r\n]+?)\]\]([^\] ]\S*) \[\[([^\]\|\r\n]+?)\]\]([^\] ]\S*) 

By replacing the (.+?) suggested by David with ([^\]\|\r\n]+?), you ensure to only capture legitimate wiki links texts, without closing square brackets or newline characters.

([^\] ]\S+) at the end ensures the wiki link expression is not followed by a closing square bracket either.

I am note sure if there is C# libraries already implementing this kind of detection.

However, to make that kind of detection really full-proof with regexp, you should use the pushdown automaton present in the C# regexp engine, as illustrated here.