Abstract Data Types

Abstract Data Types

[robinsoj]

I was reading about Ada's Abstract Data Types in Feldman and Koffman's book
and it reminded me of Object Oriented Programming.  Am I corrected is
assuming there are similarities between Abstract Data Types and OOP?  If so,
what are the similarities?

--
James H. Robinson, III

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Re: Abstract Data Types

[Pat Rogers]

robinsoj@my-dejanews.com wrote in message
<72vm3n$ks$1@nnrp1.dejanews.com>...
>I was reading about Ada's Abstract Data Types in Feldman and
Koffman's book
>and it reminded me of Object Oriented Programming.  Am I corrected
is
>assuming there are similarities between Abstract Data Types and
OOP?  If so,
>what are the similarities?


I tell people that an object in OOP is an "instance of an ADT plus
run-time polymorphism".  Said another way, an ADT exhibits
encapsulation, information hiding, and abstraction.  Ada 83 had this
covered well.  The new part (for Ada 95) from OOP is the ability of
objects to identify their implementations at run-time.

---
Pat Rogers                          Training & Development in:
http://www.classwide.com    Deadline Schedulability Analysis
progers@acm.org                 Software Fault Tolerance
(281)648-3165                       Real-Time/OO Languages

Re: Abstract Data Types

[Jeff Carter]

robinsoj@my-dejanews.com wrote:
> 
> I was reading about Ada's Abstract Data Types in Feldman and Koffman's book
> and it reminded me of Object Oriented Programming.  Am I corrected is
> assuming there are similarities between Abstract Data Types and OOP?  If so,
> what are the similarities?
> 

Niklaus Wirth, of Pascal, Modula, and Oberon fame, in describing why he
embraced OOP in Oberon, said that "object" is just another name for
"abstract data type", something he'd used for 25 years. The only
difference between OOP code and Ada-83 ADT code that does exactly the
same thing is the ADT code is easier to read and understand.

-- 
Jeff Carter  PGP:1024/440FBE21
E-mail: carter commercial-at innocon [period | full stop] com
"Son of a window-dresser."
Monty Python & the Holy Grail

Re: Abstract Data Types (and a question)

[Xavier Nicollin]

robinsoj@my-dejanews.com wrote:

> I was reading about Ada's Abstract Data Types in Feldman and Koffman's
> book and it reminded me of Object Oriented Programming.  Am I
> corrected is assuming there are similarities between Abstract Data
> Types and OOP?  If so, what are the similarities?

The following paper might be of interest:
 
William R. Cook
``Object-Oriented Programming versus Abstract Data Types''
REX School/Workshop on ``Foundations of O.O. languages'' (1990), 
Lecture Notes in Computer Science (LNCS) 489, Springer Verlag, 1991

I don't have it at hand, but I remember it compares the two approaches
wrt extension possibilities.

By the way, I have a syntactic question about the parsing of the
expression ``Abstract Data Type'': should it be undertood as
``(Abstract Data) Type'' or as ``Abstract (Data Type)''. In other words,
which one is abstract, the data or the type? My preference goes to the
``data are abstract'' version, but (AFAIK), almost everyone in the
francophone world uses the ``type is abstract'' version, i.e. they write
``Type abstrait de donnees'' instead of ``Type de donnees abstraites''.
You lucky english-speaking people with your postfix syntax don't have to
worry about this somehow pedantic question!


-- 
| Xavier NICOLLIN (mailto:Xavier.Nicollin@imag.fr), INPG (ENSIMAG)
| VERIMAG - Centre Equation - 2, ave. de Vignate - 38610 Gieres - France
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Re: Abstract Data Types (and a question)

[BSCrawford]

robinsoj@my-dejanews.com wrote:

> I was reading about Ada's Abstract Data Types in Feldman and Koffman's
> book and it reminded me of Object Oriented Programming.  Am I
> corrected is assuming there are similarities between Abstract Data
> Types and OOP?  If so, what are the similarities?

I like to think of OOP as a set of concepts to be understood in the 
following three steps: 

1. The notion that a program is conceptualized as a collection of 
interacting objects. Each object encapsulates internal data and 
exports (provides to clients) operations on the data. 

2. The notion of an abstract data type (ADT) -- a class of similar 
objects, each of which is an instance of the ADT. 

3. The notion of class-extension or inheritance, in which new 
sub-classes are derived from the root class or ADT. 

So, yes, your assumption is correct. The ADT concept is the 
important middle step of the three. 

Bard Crawford
Stage Harbor Software

Re: Abstract Data Types (and a question)

[bourguet]

In article <365BD117.3EAE@imag.fr>,
  Xavier Nicollin <Xavier.Nicollin@imag.fr> wrote:
[...]
> By the way, I have a syntactic question about the parsing of the
> expression ``Abstract Data Type'': should it be undertood as
> ``(Abstract Data) Type'' or as ``Abstract (Data Type)''. In other words,
> which one is abstract, the data or the type? My preference goes to the
> ``data are abstract'' version, but (AFAIK), almost everyone in the
> francophone world uses the ``type is abstract'' version, i.e. they write
> ``Type abstrait de donnees'' instead of ``Type de donnees abstraites''.
> You lucky english-speaking people with your postfix syntax don't have to
> worry about this somehow pedantic question!

They can't do the difference and they are lucky?

For me, abstract data type and concrete data type are the two kinds of
data type, so I think the correct translation is "type abstrait de donnees"
or "type de donnees abstrait".

BTW, when a series of adjectives followed by a noun are used in English,
usually, the correct order in french is the noun followed by the adjective
in the reverse order. That may explain your confusion.

-- Jean-Marc Bourguet

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Re: Abstract Data Types (and a question)

[Pascal Obry]

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Xavier Nicollin a �crit dans le message <365BD117.3EAE@imag.fr>...
>robinsoj@my-dejanews.com wrote:
>
>
>By the way, I have a syntactic question about the parsing of the
>expression ``Abstract Data Type'': should it be undertood as
>``(Abstract Data) Type'' or as ``Abstract (Data Type)''. In other words,
>which one is abstract, the data or the type? My preference goes to the
>``data are abstract'' version, but (AFAIK), almost everyone in the
>francophone world uses the ``type is abstract'' version, i.e. they write
>``Type abstrait de donnees'' instead of ``Type de donnees abstraites''.
>You lucky english-speaking people with your postfix syntax don't have to
>worry about this somehow pedantic question!
>


I'll go for "(Abstract Data) Type".

And you are wrong about the francophone peoples. I've never heard a guy
saying "Type abstrait de donnees''.

The ADT is for us (at least for me): "Type de donnees abstraites''. Les
donn�es
sont abstraites et non pas le type...

Pascal.


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Re: Abstract Data Types (and a question)

[Michel Gauthier]

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In article <73j4o2$npf$1@cf01.edf.fr>, "Pascal Obry" <p.obry@der.edf.fr> wrote:

>>  Xavier Nicollin a �crit dans le message <365BD117.3EAE@imag.fr>...
>> 
>>  >robinsoj@my-dejanews.com wrote:
>>  >
>>  >By the way, I have a syntactic question about the parsing of the
>>  >expression ``Abstract Data Type'': should it be undertood as
>>  >``(Abstract Data) Type'' or as ``Abstract (Data Type)''. In other words,
>>  >which one is abstract, the data or the type?   [...]
>>   [...]
>>  
>>  And you are wrong about the francophone peoples. I've never heard a guy
>>  saying "Type abstrait de donnees''.

Not that simple. You haven't, but I have. Not relevant, in fact.

This is similar to the (IMHO stupid) question of bottles that are either
half-full or half-empty. ___They are BOTH.___

Instead of asking whether the interpretation is (ad)t or a(dt), wouln't we 
ask what every interpretation could bring to the understanding of 
the underlying concept, which is nethertheless unique ?

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