4th generation languages

4th generation languages

[Roger Martinez]

I am taking a computer class and my instructor asked me to write a paper 
on "4th generation languages". Is this a common term to refer to a group 
of currently used languages? I am looking for opinions that will help me 
define what this term means. What languages make up the other 
generations?

Replies via email would be greatly appreciated.

TIA,
Roger 

Re: 4th generation languages

[Steven Nguyen]

Roger Martinez wrote:
> 
> I am taking a computer class and my instructor asked me to write a paper
> on "4th generation languages". Is this a common term to refer to a group
> of currently used languages? I am looking for opinions that will help me
> define what this term means. What languages make up the other
> generations?
> 
> Replies via email would be greatly appreciated.
> 
> TIA,
> Roger

A fourth generation language is one that is NOT procedural based. C++,
although it is object oriented, it is not a 4th generation language.  An
example of a 4th generation language would be SQL, SmallTalk,etc..


Basically, any programming language that looks like plain English.



steven

Re: 4th generation languages

[Robert Dewar]

Steven said

"A fourth generation language is one that is NOT procedural based. C++,
although it is object oriented, it is not a 4th generation language.  An
example of a 4th generation language would be SQL, SmallTalk,etc..


Basically, any programming language that looks like plain English.
"


This is wrong. 4th generation language is a term coined by Jim Martin to
refer to high level non-procedural languages, typified by Focus. Looking
like English has nothing to do with the definition. SQL would not by itself
qualify either I don't think. I certainly don't think that Jim would consider
Smalltalk to qualify, I certainly would not - I will ask him, but the 
important thing is that the plain English comment is COMPLETELY wrong.

Re: 4th generation languages

[Ed McGuffey]

Robert Dewar wrote:
> 
> Steven said
> 
> "A fourth generation language is one that is NOT procedural based. C++,
> although it is object oriented, it is not a 4th generation language.  An
> example of a 4th generation language would be SQL, SmallTalk,etc..
> 
> Basically, any programming language that looks like plain English.
> "


All wrong.

Many 4GL's contain procedures (example: Easytrieve+).  

SQL is certainly not a 4GL.  It's not even a programming language, per se.  It is
a common syntax used to query a database.  SQL is most often embedded in programs
written in a language (usually a 3GL or a 4GL), and is converted into the host
language by a preprocessor.

SmallTalk is certainly not a 4GL.  4GL's are typified as being simple and easy to
learn.  Learning SmallTalk requires an understanding of object-oriented
principles, which are deceivingly complex.  No 4GL would require you to learn this
kind of "behind the scenes" type stuff.

Another note about 4GL's: they often handle common processes automatically.
Examples of common processes are:
 1. opening an input file and reading each record in sequence
 2. putting report headers at the top of each page
 3. tallying (records read in, records written out, page number, etc.)

Re: 4th generation languages

[Aron Felix Gurski]

Roger Martinez wrote:
> 
> I am taking a computer class and my instructor asked me to write a paper
> on "4th generation languages". Is this a common term to refer to a group
> of currently used languages? I am looking for opinions that will help me
> define what this term means. What languages make up the other
> generations?
> 
> Replies via email would be greatly appreciated.
> 
> TIA,
> Roger

1. Is this a common term to refer to a group of currently used
languages?
	Yes, but less and less frequently. Still most definitely in use in the 
	mainframe world.

2. What languages make up the other generations?
	1st generation: machine language (we actually programmed in decimal or 
	                octal machine code)

	2nd generation: assembler (you have no idea of what an improvement 
	                *this* was from the 1st generation!)

	3rd generation: the langauges that include FORTRAN, Algol, COBOL, LISP, 
                        as well as newer procedural langauges (e.g.
Pascal,
	                Modula-2, Modula-3, C(++), Ada 95, Eiffel)

	4th generation: usually proprietary languages that include FOCUS, the 
	                language used by SAS Institute's products, etc. and 
	                more recent languages like xBase (I'd classify APL as
	                4th generation -- these languages tended to have 
	                reserved words that performed *huge* operations, like
	                statistical analyses, in one statement)

Good luck with the paper!

						-- Aron

Re: 4th generation languages

[Walter William Karas]

In <32668924.175A@sn.no> Aron Felix Gurski <agurski@sn.no> writes: 
...
>	4th generation: usually proprietary languages that include FOCUS,
the 
>	                language used by SAS Institute's products, etc.
and 
>	                more recent languages like xBase (I'd classify
APL as
>	                4th generation -- these languages tended to have 
>	                reserved words that performed *huge* operations,
like
>	                statistical analyses, in one statement)
...

I don't know much about it, but I think there's a bit more to this
topic.  4th gen. languages to many mean non-procedural languages.
For example, a statement in a data base query language specifies
a subset of a table or a new table created from existing tables.
But it doesn't specify how or when it should be done.  There
are "rule-based" languages that consist of "if this, then that"
type statments that aren't executed sequentially.  They're activated
by triggering their initial condition, directly or indirectly.
As best as I can understand it, in a 3rd gen. language, you tell
the computer how to do something.  In a 4th gen. language, you
tell the computer what something is, and it figures out how
(and when) to make it and how to use it.

You probably want to read something about Prolog.  I've also
heard Fuzzy Logic mentioned in the same breath as 4th gen.
languages.

Re: 4th generation languages

[Jon A. Lambert]

Aron Felix Gurski <agurski@sn.no> wrote in article <32668924.175A@sn.no>...
> Roger Martinez wrote:
> > 
> > I am taking a computer class and my instructor asked me to write a
paper
> > on "4th generation languages". Is this a common term to refer to a
group
> > of currently used languages? I am looking for opinions that will help
me
> > define what this term means. What languages make up the other
> > generations?
> > 
> > Replies via email would be greatly appreciated.
> > 
> > TIA,
> > Roger
> 
> 1. Is this a common term to refer to a group of currently used
> languages?
> 	Yes, but less and less frequently. Still most definitely in use in the 
> 	mainframe world.
> 
> 2. What languages make up the other generations?
> 	1st generation: machine language (we actually programmed in decimal or 
> 	                octal machine code)
> 
> 	2nd generation: assembler (you have no idea of what an improvement 
> 	                *this* was from the 1st generation!)
> 
> 	3rd generation: the langauges that include FORTRAN, Algol, COBOL, LISP, 
>                         as well as newer procedural langauges (e.g.
> Pascal,
> 	                Modula-2, Modula-3, C(++), Ada 95, Eiffel)
> 
> 	4th generation: usually proprietary languages that include FOCUS, the 
> 	                language used by SAS Institute's products, etc. and 
> 	                more recent languages like xBase (I'd classify APL as
> 	                4th generation -- these languages tended to have 
> 	                reserved words that performed *huge* operations, like
> 	                statistical analyses, in one statement)
> 
> Good luck with the paper!
> 
> 						-- Aron
This reply concurs with my understanding of the definition of these
terms.  At least with the definitions of the 1st through 3rd generation.  

4th generational languages are those which are non-procedural.
SQL certainly falls within this category, for it is purely non-procedural.
It is also not a very robust language.  

I have also heard C referred to as a 2 1/2 generation language.  This
is probably because of its abililty to access a level of hardware control
that assembler languages have.  

Vendors frequently refer to their new languages as 4GLs.
Particularly those that involve GUI.

You'll find its become a buzzword that really doesn't have
have the meaning that the original authors intended.


 

Re: 4th generation languages

[Robert Dewar]

iJon said

'You'll find its become a buzzword that really doesn't have
have the meaning that the original authors intended."

I am a little puzzled by the plural here, surely author. The term 4GL was
coined by James Martin, so where are your other authors here? 

Re: 4th generation languages

[Robert Dewar]

Aron said

"        4th generation: usually proprietary languages that include FOCUS, the
                        language used by SAS Institute's products, etc. and
                        more recent languages like xBase (I'd classify APL as
                        4th generation -- these languages tended to have
                        reserved words that performed *huge* operations, like
                        statistical analyses, in one statement)
"

no, no, no! APL is definitely NOT a 4th generation language. Of the essence
in Jim Martin's notion of 4GL's is the idea of declarative languages
as opposed to imperative languages. APL is definitely an imperative language,
sure it is a very high level language (at least in some respects), but a
4GL is not simply a very high level language!

Re: 4th generation languages

[Jon S Anthony]

> A fourth generation language is one that is NOT procedural based. C++,

Well, that's probably one of a zillion definitions.


> example of a 4th generation language would be SQL, SmallTalk,etc..

Huh?  SmallTalk is procedural and you can even make a reasonably good case
that SQL (such as it is...) is also.


> Basically, any programming language that looks like plain English.

????????  This conflicts with your earlier claim.  Things like Mercury
(purely declarative logic programming language) don't look anything
like "plain English".

/Jon

-- 
Jon Anthony
Organon Motives, Inc.
Belmont, MA 02178
617.484.3383
jsa@organon.com