Sequential programming language?

Question

What exactly is behind the notion of "sequential programming language" ?

I couldn't find a proper / deep description for that. I clearly see what a sequential algorithm is, but a programming language.

Sequential could be opposed to procedural, but...

What would be a language said "strictly sequential" ? Is it only a matter of giving or not the possibility to deal with functions ?

I know that this question is a bit too general and would require more than a simple Q&A, but an introduction and/or some good pointers on the subject would be greatly appreciated.

EDIT : Well, after further reading (thanks to msw and Edorka), I realize that the above quoted assumption is the result of my misunderstanding of some basic vocabulary and relies on nothing concrete. And consequently this question becomes pointless. But thanks for your time and precious developments guys!

EDIT :sequential would be better opposed to...

• Event-driven programming
• Concurrent computing
• Parallel computing
• Declarative programming
• Quantum programming

Answer 1

I would say — lacking further context — that sequential could be synonymous with imperative or contrasted with "event-driven", "concurrent", "parallel", "declarative", or "quantum".

I don't know where you got your quoted text, but if you unroll a procedural program it is "sequential" and so from a theoretical perspective, it's a useless distinction.

Answer 2

Maybe you can consider Locomotive Basic 1.0 as sequential because every line had a number before, there were not functions as we now use then, you do GOSUB <line number> or GOTO <line number>. As example:

5 CLS;
10 PRINT "WHAT YEAR IS NOW?"
20 READ YEAR%
30 IF (YEAR% < 1981) THEN GOTO 50
40 PRINT "THIS IS THE FUTURE, DUDE"
50 END;

Of course these programs had an start and end points and were run on a single CPU. I suppose that the difference with procedural languages is that this last ones are not limited to a single run thread.