Stability of PCT, PGE, NQP, PIR for HLL development

[Moritz Lenz]

Am 24.01.2011 13:08, schrieb Ville Koskinen:
> 1. How stable are PCT, PGE and NQP? (Or is it just NQP nowadays?) In
> other words, if I start writing an HLL implementation today for Parrot
> 3.0.0, will the implementation still work on Parrot 4.0?

NQP is fairly stable. It's a (mostly) subset of Perl 6, and hasn't 
changed much recently (except in cases where functionality has been added).

I don't know if the deprecation policy covers NQP, but I don't think 
there will be stability guarantuees between two major version numbers 
(and thus 4 "supported" releases, iirc).

But notice that even if NQP stays stable, your programs can still break 
if you call API methods that change.

> but based on existing implementations (Rakudo in
> particular), it doesn't seem possible to write a full compiler with just
> NQP;

Note that significant parts of Rakudo's PIR predate NQP (or at last the 
NQP-rx variant), and just haven't been ported to a more high level 
language since then. The presence of PIR code doesn't always imply it's 
necessary to have that piece of code in PIR.

Cheers,
Moritz