----- Original Message -----
From: mAsterdam <[EMAIL PROTECTED]>
Date: Wednesday, September 8, 2004 8:31 pm
Subject: Re: multiple languages clarification - newbie
> Joseph Ryan wrote:
>
> >>Can someone provide clarification on what mixing languages will
> >>look like in practice, or point me to where its explained?
>
> <delurk> Warning. This is perl 7 and a half:
>
> #!/usr/bin/perl -w
> use prolog;
>
> prolog: # prolog tells us:
>
> needs_support_of(Db, Da):-
> designer(A, Da),
> designer(B, Db),
> needs(A, B).
>
> designer(perl, larry).
> designer(parrot, dan).
> needs(perl, parrot).
>
> prolog. ; # or some other end-quote
>
> for needs_support_of {
> print; # prints 1st in the signature of the unification,
> # predicate, 2nd .. nth in the signature of the
> # match (for one member of the result).
> }
>
> __END__
>
> </delurk>
You could do that in Perl6 (or any Parrot based language) as:
eval "
needs_support_of(Db, Da):-
designer(A, Da),
designer(B, Db),
needs(A, B).
designer(perl, larry).
designer(parrot, dan).
needs(perl, parrot).
", "prolog";
for needs_support_of() {
print; # prints 1st in the signature of the unification,
# predicate, 2nd .. nth in the signature of the
# match (for one member of the result).
}
Assuming, of course, that there exists a prolog->parrot compiler.
You could even have your syntax if you use a macro:
macro prolog is parsed(/
\: ([
<[^p]>+ ::
| <!before ^^prolog\.\s*$$> p
]+)
/) {
eval($_, "prolog");
}
- Joe
