Semantically I think it's great. .NET has a bunch of these especially in LINQ. A parsing failure isn't necessary an error. Sometimes it is, sometimes it's not

Semantically I think it's great. .NET has a bunch of these especially in LINQ. A parsing failure isn't necessary an error. Sometimes it is, sometimes it's not. Even if exceptions weren't expensive, catching exceptions on all parsing (as you would in Java) is just ugly and, I would argue, not semantically correct. In my opinion, one should throw often but catch infrequently. Most of my large applications have a very small number of catches. It's also perfectly reasonable to move this down a layer and have Parse return an Option type and choose to handle did-not-parse case or don't and let that trigger an exception.