A. Stepanov on the STL

http://www.antiquark.com/escape/public_html/stepanovusa.html

by sfk • 17 years ago

40 20 17 years ago

zephjc• 17 years ago

Stepanov is a really smart guy, but I find his arguments that OOP methodology is "wrong" or somehow is no good, doesn't hold water. The truth is that a lot of the world is build on at least some OOP principles and that they have worked for countless designs, and been included into languages by lots of other really smart people.

It also seems like this interview was done quite some time ago (see his comments about generics in Java) but I can't find a date.

Nevertheless, a very interesting interview.

sorbits• 17 years ago

I think you are misrepresenting him.

He says his paradigm is “start with the algorithm” (to make it generic) and that does not work in the OO model, and as an example he gives a simple max(a, b) function which he wouldn’t know how to write in Java.

The “OOP principles” adopted by others, which you think voids his argument, you can argue are also used by Stepanov himself. He just calls it data abstraction (iirc).

seancribbs• 17 years ago

His argument actually seems to point to dynamically-typed functional programming, which is not surprising, considering his work with Scheme.

huhtenberg2• 17 years ago

Boy, that's old.

> Java is a very new language

:-)

d0m• 17 years ago

T max<T>(Comparable a, Comparable b) { if (a.compareTo(b) < 0) { return a; } else { return b; } }

Or something..

Explicitly specifying that a and b needs to be comparable instead of shooting an endless template error message.

And: "My approach works, theirs does not work." explains perfecly why C++ is what it is.

jpr• 17 years ago

Equality and comparisons in presence of subclassing etc. are not the business of a sane man. I think it is impossible to write an .equals() in java that satisfies all the relevant laws people usually assume from it.

joshhart2• 17 years ago

In Eclipse:

Alt-Shift-T for refactor. Select "Generate Hash-code and Equals".

sketerpot2• 17 years ago

It's possible to be locally sane. For example, suppose you define an abstract Number class, and define subclasses for ComplexFloat and IntFraction numbers. You could define .equals() methods on each of those that only compare to the same type, and work correctly. You don't always have to deal with weird issues.

huhtenberg2• 17 years ago

"Your approach" is what Stepanov was referring to as "concepts" about .. erm .. 10 (?) years ago. It is effectively a template argument constraint system.

Concepts were one of the most expected features of C++0x, the one that got just recently dropped from the consideration due to being "not ready".

sketerpot2• 17 years ago

Is that similar to this Haskell code?

    max :: Ord a => a -> a -> a
    max a b = if a > b then a else b

The concepts that Stepanov was talking about, where algorithms are defined for classes of data structures supporting certain operations (iteration, comparison, etc.), sounds very familiar to anyone who's familiar with Haskell's type classes.

tumult• 17 years ago

Yep

jemfinch2• 17 years ago

That Haskell code, as I understand it, will dynamically dispatch the call to max through the Ord typeclass dictionary passed at runtime. The C++ code will statically choose the appropriate function.

brendano• 17 years ago

The article is old, from when Java was new. His criticism was correct back then. Java didn't get generics until 8 years after it was introduced. (Java 1.5: http://en.wikipedia.org/wiki/Java_version_history )

davidmathers• 17 years ago

He has a book now, Elements of Programming: http://www.amazon.com/dp/032163537X/

ryanpetrich• 17 years ago

"As the chief proponent of Java at SGI told me: 'Alex, you have to go where the money is.' But I do not particularly want to go where the money is - it usually does not smell nice there."

I really love this quote

A. Stepanov on the STL

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