[Haskell-cafe] Wikipedia on first-class object

[Wolfgang Jeltsch]

Am Freitag, 28. Dezember 2007 08:12 schrieb Cristian Baboi:
> On Thu, 27 Dec 2007 17:35:54 +0200, Jonathan Cast
>
> <jonathanccast at fastmail.fm> wrote:
> > Only on Von Neuman machines.  Haskell implementations are not required
> > to run on Von Neuman machines.  That's why the language is called
> > functional.  (Imperative languages, by contrast, are just abstractions
> > of the underlying Von Neuman architecture, which is probably the source
> > of your confusion).
>
> Can you tell me what is it that make a language imperative ?
>
> When I learned about formal grammars and languages, there was no
> discussion about this.

This is because a formal language (set of words) only consideres the syntactic 
aspect and formal grammars are only about describing formal languages.  In 
contrast, imperative vs. declarative is about semantics.  A language is 
imperative if programs written in this language say how something should be 
done instead of what should be the outcome.  This description is rather 
informal, of course.

Best wishes,
Wolfgang