By now I work with asp.net and C#. I have done a decent work in Java as well. I am planning my career in such a way I should be language-agnostic someday. What are the things that I need to learn?
First would OOP paradigms as its speaks about the Class design. Are there any others?
To be language agnostic you need to have experience in all of the common styles and types of languages.
Also:
Some typing styles:
Some different runtime styles:
Lower level stuff:
On top of that I would say you need experience of some concurrent programming and something event driven. You should probably also make sure you know something about the various domains such as web programming (client & server), rich client development/desktop, games. You might also want to learn about embedded programming, or dedicated hardware (like games consoles), and mobile development is becoming an increasingly relevant domain.
Others have also mentioned that it's worth getting some experience of Generic programming and Meta programming approaches.
When you learn these paradigms avoid just learning the syntax and writing in your old style. I've seen many C# devs write JavaScript as if it's statically typed. Don't do this, try to learn the language paradigms and embrace them.
If you've done all of this, the differences between languages will become largely syntactical so switching will become a fairly simple exercise of learning some new syntax.
Don't forget though that modern programming is almost always dependant on a framework, so familiarising yourself with the common and popular frameworks for each language you learn is also critical. Knowing C# is irrelevant without .net.
I don't think you can become truly language agnostic. I find that I "think" in my current language (at the moment C#).
However, having said that, I think you might be able to separate the design from the code by trying to think in pseudo code rather than a specific language, and actually write it down in this format. This could help you concentrate on the design and architecture decisions rather than the implementation in your current language. The drawback with that - as Simon points out - is that the language and framework you ultimately use will inevitably influence the design. So as your design develops it will become increasingly tied to the language & framework.
Reading your question and some of the answers one can have the impression that you equal "language agnosticism" with "knowing every paradigm on earth".
I'm not sure whether knowing every paradigm that exists or knowing an assorted range of languages, spanning several paradigms and types of languages makes you "language agnostic".
It's like saying that having practiced all religions makes yourself religiously agnostic.
I think a language agnostic person regarding programming languages should be someone that doesn't know how to program in any language at all or doesn't care what language he/she is asked to programm with.
That said, some people say a true programmer can program in any language given access to that language's documentation.
If that is what you mean by "language agnostic" then almost any experienced programmer can program in any language he/she gets forced to work with, given access to the language documentation.
Maybe you want to be "language polytheist".
I myself am competent in several language paradigms but I'd prefer OOP when it aplies. So I guess I'm not agnostic.
You will hardly find anyone who doesn't prefer a certain paradigm or language given the liberty to choose.
It's not just the languages, Java itself has so many different modes that you could spend years just learning them all. You could learn:
And a hundred things I'm missing--JUST within java.
If you spend years covering the breadth (learning every language) you'll have trouble gaining the depth to work effectively in any one of them.
I'm not saying that learning a new language is EVER a problem, you shouold be actively doing so! I try to pick my next job based on what I can learn (what I haven't done yet), but I don't often pick a random language and learn it any more--Last time I tried that was with Scala and I left somewhat humbled...
