I'd say that when it's efficient to learn something by implementing it yourself is relatively rare.

Many big things you mention (language implementations, GUI toolkits, RDBM systems, etc.), IMHO, make up a small precentage of the number of libraries or applications out there. For every RDBM, there are a few dozen SQL-related modules that could be implemented by any competent coder. You also mentioned Operating Systems, which actually is something that many people have learned by creating their own (maybe not a sophisticated system that would find a real-world use, but enough to get a basic shell up).

Perhaps in other areas of life (such as heart surgeons and drivers) what you can learn-by-implementation is limited, but there are quite a lot of problems in programming that can be learned that way.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated

In reply to Re: Re: Learning methods (valid use for reinventing the wheel?) by hardburn
in thread Learning methods (valid use for reinventing the wheel?) by Fengor

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