Re: Forking stables. was Re: language translator help

[Chris Beggy]

Neil Jerram <address@hidden> writes:

>     Chris> See what he has to say about:
>
>     Chris>   1. language versioning 
>     Chris>   2. compatibility between versions
>     Chris>   3. interface stability
>
> Er... not a lot.  It's a great article, but I noticed nothing in
> particular on these subjects.  Rather, it's all about designing a
> language so that the community can help grow it, and in particular
> about why he thinks that Java needs overloaded operators.
>
> (Oh, perhaps that was your point ...?)

Right :-) Thanks for reading and commenting.

Steele doesn't talk about these because they are already decided
issues, whose treatment is widespread in engineering and design
cultures that I've seen.

For lots of language/system designers (and users too), there's
nothing interesting about language versioning, compatibility
between versions, and interface stability:

   1. A language release with a new version number is an improvement.  
   2. There is backward compatibility to old versions in the new system
   3. Interfaces are stable.  

Deviations from any of these features are compensated by
emulation modes, compiler, interpreter, or usage warnings; or a
rename of the language or system.  Progress is difficult without
these features.

This is my roundabout way of saying that stability, backward
compatibility, and emulation are ways to continue using code you
can't modify. That's an answer to ttn's (rhetorical?) question.

These features ensure the ability to reuse and learn from working
code someone, like ttn, has offered to share as well.  The
surprising difficulty to do that is my complaint about guile.

Chris