dynamic classes and duck typing

[Walter Bright]

dsimcha wrote:
> Right, but sometimes (though certainly not always) it's better to provide a
> meta-feature that solves a whole bunch of problems (like better templates) and
> then solve the individual problems at the library level, rather than add a
> language feature specifically to address each need.

Yup. The hard part, though, is figuring out what the magic set of 
seminal features should be.


> One thing D does very well is
> allow you to do the same kind of metaprogramming solutions you would do in C++,
> except that the result doesn't suck.  For example, std.range implements
> functional-style lazy evaluation as a library, and does it well.  The point is
> that, if you can't deal with the complexity of having real templates, you better
> be prepared for the complexity created by not having them.

Right. A "simple" language pushes the complexity onto the programmer, so 
he has to write complicated code instead. D programs tend to be 
dramatically shorter than the equivalent C++ one.


> Having never done it before, I really cannot imagine how people get any work done
> in a language that doesn't have either duck typing or good templates.  It's just
> too rigid.  It seems like modern statically typed languages like Java and C# end
> up adding tons of ad-hoc workarounds for lacking either of these as
> well-integrated language features.  The best/worst example is auto-boxing.

I tried programming in Java.

A friend of mine had an unexpected insight. He used Java a lot at a 
major corporation. He said an IDE was indispensable because with "one 
click" you could generate a "hundred lines of code". The light bulb came 
on. Java makes up for its lack of expressiveness by putting that 
expressiveness into the IDE!

In D, you generate that hundred lines of code with templates and mixins.