Re: Ada noob here! Is Ada widely used?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 25 May 2010 16:24:20 +0200, Georg Bauhaus  
<rm.dash-bauhaus@futureapps.de> a écrit:
> Yes.  Ada/Ed, though, being an Ada 83 interpreter, being
> written in SETL, not C, and being prototypical for GNAT,
> indicates that C is not necessarily the single language for
> writing high class compilers---as some have implied.
> I'm sure you know that is the case for some other languages,
> too.
> GNAT is one compiler where everyone can convince themselves,
> since the sources are open to the public.

Depends on the initial state. For precursor or near to be so, this starts  
with a bootstrap sequence : the compiler is written either in assembly, or  
C (or may be Basic), or something of the like. This state is short, and as  
soon as possible it is rewritten in the compiler's target language itself,  
and it's funfair time when the compiler is able to compile it self (a  
great and memorable moment of history). This first part of the history is  
short, then after, all goes with the compiler's target language (or a  
subset for safety and stability insurance).

    FreePascal is written in FreePascal.
    GCC is written in (GNU)C
    GNAT is written in Ada
    Janus (as far as I know and read about) is written in Ada
    SmallEiffel and its successor SmartEiffel was written in Eiffel.
    There are a few assembly written in assembly.

For other kind of language, that's a bit different : you have some Prolog  
interpreters written in LISP and some LISP interpreters written in Prolog  
(for fun and proof of some concept... and it shows both are indeed Turing  
machines).

This draw the line below which a language is an implementation language or  
a Domain Specific Language.

If a compiler can be advantageously (mostly with efficiency in mind)  
written in it's target language, then, this target language is an  
implementation language. If not, it is probably a DSL (Domain Specific  
Language), like Prolog and LISP are (well, to be honest, LISP is a special  
case, as it could be an implementation language on some architectures ;  
assembly is a special case also).

To be inquisitive : do some one have an idea of the implementation  
language of Basic interpreter and compilers ? I do not have an idea.

-- 
There is even better than a pragma Assert: a SPARK --# check.