I'm not going to claim that there are no legitimate reasons to hire people who are narrow experts in Blub (and only Blub), but I'm having a hard time thinking of any.
At an established company, you've got the luxury of time -- there's rarely a good reason to "need an expert right now" that isn't just a contractor. At a startup, where hiring the wrong person is a disaster, hiring an "expert right now" is like holding a loaded gun to your head. Ideally, you should be hiring "T" people -- lots of breadth, with lots of depth in at least one area.
A truly good programmer will pick up your language/framework in days, and be at full productivity in months, even from scratch. It's hard to do better than that.
Just because I've never written Erlang doesn't mean that I will automatically try to write a random-number generator (say) the first time I need one in Erlang. I have enough experience to look for a library function first.
Empirically, NIH tends to be more common in single-language developers, not less. People who place a lot of value on their "expertise" in Blub tend to do so because they're over-weighting the importance of their memory of the API details. When they don't automatically remember something, they leap to the conclusion that it doesn't exist. They're also typically a less-experienced cohort than people who have written in lots of different languages.
That's called "laziness", and is even more likely than NIH syndrome to be mitigated by experience. Certainly, having lots of coding time with a single language doesn't make you less lazy, and having lots of experience with different languages doesn't make you lazier.
The point isn't that the generalist programmer will be 100% correct in all the details in new language, it's that they'll be able to quickly (and correctly) implement the important parts in whatever language you're using. Idioms tend to be the low-order bit of a solution anyway.
Cheers
It probably took a couple of months full time in python before I had enough understanding of the std lib to know where to find everything (I sat down and read through a description of most of the functions in there).
There are still plenty of libraries that would have made my life easier if I knew about them. I'm sure there are plenty more.
Having said all that, that's just for example. When it comes to hiring I'd still pick a good experienced developer over a specific language expert for a full time position. For me it's not so much about the understanding of a specific language as it is the appetite for understanding computers / systems in general that makes truely good developers.
Ultimately the task is going to dictate the best type of hire. Short term contract, get a specific expert. Long term hire, find someone who actually enjoys developing software :)
It's something to do with how critical the library functions are to you / your system. I would never write my own compression software, but I can see why people would just to learn about the trade offs.
Third party libraries are also listed here:
http://go-lang.cat-v.org/pure-go-libs
And the ecosystem is not so broad or mature that you would miss significant libraries because there are too many options and you just didn't find them.
Otherwise you have a methodology problem. You don't do daily standups, where you'd have the opportunity to say "Yesterday, I started implementing X because I couldn't find a library" and more experienced coworkers would tell you "Use library Y instead".
Any project should have time allocated for "tech debt" and that's where this sort of thing gets addressed.
Blub is a very useful tool but has a bunch of quite esoteric gotcha's that an expert will be able to avoid due to long experience.
Expert has used almost all of the Blub framework over the years, including the more popular third-party addons and already knows what's best and fastest in a variety of situations without having to think about it much.
"A truly good programmer will pick up your language/framework in days, and be at full productivity in months, even from scratch. It's hard to do better than that."
Yeah, but then HR won't be able to tick off the 'Blub expert' box and, well, nobody would ever get hired! Or something...
And the crappier your language and libraries, the more time it takes to be an "expert."
My other theory is that it's a lot harder to track down bugs for a newcomer because like C (and unlike Python in most cases), importing functionality from another file is implicit. That is, when you 'require' a bunch of files, there's no indication which functions are coming from where. For me, this is one of the things Python solves marvelously (it's generally considered bad form to 'import *').
This sounds great. I'd hate software made in the way some "community" wants. Community is the other name for committee.
Especially since being a good programmer is more about design, choice of interfaces, reactivity to change, etc. which are by definition language agnostic.
I firmly disagree that Ruby requires any less effort than say C, C++, Java or LISP to become an expert.
This is FUD. It's a different way of doing things, not harder. I live inside Pry which makes it rather easy to figure out what's going on.
I really don't think it's FUD to say that Rails has gotten much bigger in the past 5 years, and it's definitely not FUD to say that as codebases and tooling grows, so does barrier to entry.
The specific thing I guess you're objecting to is that it's harder for a noob to understand implicit imports and where something is coming from if you don't know much about what you're importing. If you use a tool to solve that language deficiency, that doesn't remove the deficiency from the language. By that logic, adding an IDE to Java makes it a very concise language.
"it's a lot harder to track down bugs for a newcomer"
This statement is FUD. You seem to be defining "language deficiency" as "hard for a noob before they become proficient". I think that is absurd.
An expert still needs time to become familiar with a large codebase and architecture. I wonder if a competent programmer could simply learn the language in addition during this period.
Granted Go doesn't have as many libraries as the more established languages, but to say there aren't many and there's "nothing to learn besides the language" is just flat out wrong.
Just for starters there's http://code.google.com/p/go-wiki/wiki/Projects
And there's probably more to a lack of an ORM other than "Go is immature." It's a fairly common opinion among the Go community that ORMs are not worth their complexity. I tend to share that opinion myself, after having worked with a few in a couple different languages.
As to only the lack of ORM would make Go immature? Honestly I don't know. There are tons of software written in JavaScript; do they make JavaScript mature? Hell no.
Really? Because we managed to get just fine without one for decades...
I know that I've used Hibernate for years. I've used it with DTOs. I know that it does provide a certain benefit for simple reads and writes. Unfortunately, Hibernate was designed to work in a disconnected manner like the Web. As a result you get into complications of session management. This is just one example of Hibernate maintenance costs.
Now I use Spring JDBC. This removes the noise of the checked exceptions, connection management, transactions, just like Hibernate. But I write simple or complex SQL in one place and map in and out contently.
In C# the session management is no big deal: you access everything via the Repository pattern, turn on trait injection and just make sure any repository method that will need a session has a transaction attribute. If you need to do a series of read/writes in one transaction you throw that whole method into the repository class and put a transaction trait on that method.
In any solution you come up with you'll either need a repository that handles sessions and so on, or you'll have to explicitly connect to the db every time you need it. Either case will be more work than what I've done with this solution.
In a multi-paradigm language you wouldn't be tied to using an ORM but you should still use something that provides some kind of anti-corrupt support. In an OO language you can have nothing but objects so there is nothing else your database library can return. It may as well return objects that represent the records rather than, say a list of strings.
It depends if you're going to spend years training someone or if you need an expert right now.
My experience is that it is impossible to maintain expert level skills in more than one or two language + library environments. You can remain familiar with other environments but you don't have the time to be an expert.
While I sometimes switch between C-family languages for different projects, it can take months to get up-to-speed with the changes in a language and its environment since you last programmed in it. I'm talking about situations where I know the language well but the environment has changed. Languages change a little but the libraries they use can change dramatically. And along with the change comes a whole body of implied knowledge about how to safely and effectively use it all and this impacts on how you use the language itself.
If you've literally never programmed in a language before, it can be a few years before you know about all the eccentricities, before you understand why the language follows certain patterns, before you understand the risks with certain behaviors.
If you need an expert now, not in 12 months time, then they need to know both the language and the environment. If you can wait a couple months, then they still need to know the language.