Re: How to get Ada to ?cross the chasm??

[Lucretia <laguest9000@googlemail.com>]

On Friday, 11 May 2018 10:09:34 UTC+1, Paul Rubin  wrote:

> But, you unquestionably understand the issue better than I do.
> 
> What I don't understand is, why didn't the same issue apply to Pascal?

Pascal never had packages, only later dialects did. Pascal was developed as a teaching language, Wirth said that it was down to implementers to extend the language. It was underdefined and should never have been extended the way it was, IMO, it should've been kept as a simple teaching language.

> > the withed declarations are (re-)compiled on the fly when the withing
> > unit is compiled. The penalty for such recompilation is smaller today,
> > with faster machines and compilers.
> 
> It's just the .ads that's included, right?  Was the speed that bad an
> issue even on the old machines?  Is Ada really harder to compile than
> Pascal?  I've always liked this article even though I never used Turbo

Yes it is. See the grammar, it's very ambiguous. Pascal's grammar can be taken from the page and written directly as functions to make a a recursive descent parser.

When creating a parser for Ada, you need to first work out where to put pragma, because for some stupid reason, they didn't bother to include it in the correct places in the grammar, seriously, search for "pragma" http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-P.html

You then need go through and sort out the grammar so it will work for you, whether hand coding or tool. You then have *syntactic* names all over the place which is part of overload resolution.

It's tricky.