Took a very quick look at Coderay. If I'm not mistaken, it looks like a Regexp-based parser/compiler, rather than any sort of parser with an actual grammar. To

Took a very quick look at Coderay. If I'm not mistaken, it looks like a Regexp-based parser/compiler, rather than any sort of parser with an actual grammar. To be honest, while my inner nerd shudders at this, it makes a little sense as some of the languages in that list (Ruby) have only recently had formal grammars defined. That said, I think it would take me more than ten minutes to implement a scanner for F#, which I don't know, using Coderay, which I also don't know. I could probably get it done in about a day, maybe two for debugging and testing. There is no way in hell I would spend that kind of time on a job application, and as a nerd that has gone into management, I wouldn't ask an applicant to do so either. What has worked well for me in the past is to ask for either a link to their GitHub repository, a code sample, or have them solve a quick five-minute problem over Skype or IM. If the interviewee passes that bar, we then do something more in-depth during the interview as a pair, timeboxed to about half an hour. This has proven effective at weeding out the untalented and unworkable, without asking potential hires to sacrifice a huge amount of their time.