[Dan Sugalski]
IMHO also the fact of not merging the type "ontologies" but carrying somehow both around is a bit scary.
It's mildly scary, sure. On the other hand, it's not really any more scary than, say, writing code in COBOL, C++, Basic, or Fortran and calling them from C. Or vice versa. While that's a tad odd, you can pretty easily get used to it, and it works out well.
You also don't have to mix languages. That's certainly one of the advantages, but it's far from required. (This is assuming, of course, that there's a performance gain to be had in targeting the parrot back end--if there isn't, then it's reasonably pointless to do so)O
If one have to call conversion function from Python/Perl code to deal with the other ontology or deal with unnatural behavior avoiding mixing languages will remain the best thing, also for the problem of reading code in the other language. But for C extensions the situation is a bit different, they should target one ontology (or not?) and then using the extension from both languages will be not that natural. And C extension in Python typically extend the ontology, introduce new types ... regards, Samuele Pedroni.