«

I haven't seen any links to this here: Barbara Liskov has won the Turing
Award:

http://web.mit.edu/newsoffice/2009/t...ov-0310.html/?


[quote]
Institute Professor Barbara Liskov has won the Association for Computing
Machinery's A.M. Turing Award, one of the highest honors in science and
engineering, for her pioneering work in the design of computer
programming languages. Liskov's achievements underpin virtually every
modern computing-related convenience in people's daily lives.
[end quote]

Liskov is well known for the "Liskov substitution principle". She also
created the language CLU, one of the most important inspirations to
Python, and coined the term "pass by object" (also known as "pass by
object reference") to describe CLU's then novel argument passing
behaviour. Such behaviour has since become a virtual standard for OO
languages such as Python and Java.



--
Steven

On Thu, Jun 25, 2009 at 12:34 AM, Steven
D'Aprano<> wrote:
> I haven't seen any links to this here: Barbara Liskov has won the Turing
> Award:
>
> http://web.mit.edu/newsoffice/2009/t...ov-0310.html/?
>
>
> [quote]
> Institute Professor Barbara Liskov has won the Association for Computing
> Machinery's A.M. Turing Award, one of the highest honors in science and
> engineering, for her pioneering work in the design of computer
> programming languages. Liskov's achievements underpin virtually every
> modern computing-related convenience in people's daily lives.
> [end quote]
>
> Liskov is well known for the "Liskov substitution principle". She also
> created the language CLU, one of the most important inspirations to
> Python

Erm, Wikipedia (which is generally excellent on programming topics)
seems to disagree with you.

http://en.wikipedia.org/wiki/Python_...mming_language)
"Influenced by ABC, ALGOL 68,[1] C, Haskell, Icon, Lisp, Modula-3, Perl, Java"

Unless you mean it influenced Python indirectly by way of the
aforelisted languages...

Cheers,
Chris
--
http://blog.rebertia.com

Chris Rebert wrote:
> On Thu, Jun 25, 2009 at 12:34 AM, Steven
> D'Aprano<> wrote:
>> I haven't seen any links to this here: Barbara Liskov has won the Turing
>> Award:

It was posted about the time of the announcement, but is worth the reminded.

>> http://web.mit.edu/newsoffice/2009/t...ov-0310.html/?
>>
>>
>> [quote]
>> Institute Professor Barbara Liskov has won the Association for Computing
>> Machinery's A.M. Turing Award, one of the highest honors in science and
>> engineering, for her pioneering work in the design of computer
>> programming languages. Liskov's achievements underpin virtually every
>> modern computing-related convenience in people's daily lives.
>> [end quote]
>>
>> Liskov is well known for the "Liskov substitution principle". She also
>> created the language CLU, one of the most important inspirations to
>> Python

This inspired me to to spend a couple of hours finding and reading a CLU
manual.

> Erm, Wikipedia (which is generally excellent on programming topics)
> seems to disagree with you.
>
> http://en.wikipedia.org/wiki/Python_...mming_language)
> "Influenced by ABC, ALGOL 68,[1] C, Haskell, Icon, Lisp, Modula-3, Perl, Java"
>
> Unless you mean it influenced Python indirectly by way of the
> aforelisted languages...

Python's object model, assignment semantics, and call-by-object
mechanism, and that name, come from CLU. Whether Guido knew of it
directly or not, I do not know. To the extent that the above is part of
the heart of Python, I think Steven's statement stands pretty well.

> Python's object model, assignment semantics, and call-by-object
> mechanism, and that name, come from CLU. Whether Guido knew of it
> directly or not, I do not know. To the extent that the above is part of
> the heart of Python, I think Steven's statement stands pretty well.

Why do you say that? ISTM that Python is much closer to Smalltalk than
to CLU in its object model. CLU is statically typed (and it is important
to its notion of program correctness that it is statically typed);
Smalltalk and Python aren't. In addition, Smalltalk and Python have
inheritance; CLU (deliberately) doesn't. Liskov reported that she didn't
know about Smalltalk until 1976.

I believe that Python's, CLU's, and Smalltalk's assignment semantics
actually all come from Simula. I would claim the same for the
call-by-object mechanism - except that this is probably best described
as coming from LISP (in the sense of caller and callee sharing
references).

FWIW, Simula has also inheritance, but that specific notion of
inheritance did not transfer to any other language, except for Beta.

Regards,
Martin