Hacker News Reader

Comment by simias | Hacker News Reader

I appreciate the commitment to semver, it seems that the breaking change is a rather small one, unless I'm missing something.

View on HN

> I appreciate the commitment to semver

There is no commitment to semver from SBCL's side. Rather, it's trying to follow calendar years with at least one release each of the 11 months and a major release in the end of the year.

Uh, I take it back then. I get this versioning scheme for something that don't have a reasonably application for semver like an operating system for instance, but a programming language? I don't really see the point. If you go that way you might as well tag it "SBCL 2020" or something like that to make it clear.

But I suppose that's pure bikeshedding and it doesn't really matter.

SBCL is an implementation. The programming language Common Lisp is set in stone by a standard.

Does that matter? SBCL includes a lot of nonstandard extensions.

It matters a lot. But the extensions are important and warrant compatibility tracking.

I'm sure SBCL is committed to follow the Common Lisp standard, so as long as you don't stray outside of that you don't have to worry too much.

Is that feasible? Last I used Common Lisp, I seem to recall the spec being rather ambiguous on a number of important practical points, so any real program couldn't depend on only CLTL2.

For example, Maxima lists a number of implementations that can compile it, and says "Ports to other ANSI Common Lisps should be straightforward and are welcome" [1]. The source code is full of #+ #- conditionals.

[1]: http://maxima.sourceforge.net/lisp.html

CLtL2 is not the spec for ANSI CL. The spec was published a bit later and is a different document.

The actual spec for ANSI CL is basically almost the same as this document : https://franz.com/support/documentation/cl-ansi-standard-dra...

ANSI CL is a spec of the language. Programs like Maxima use a lot of features not covered by the language specification and Maxima has been written over a long time and has to deal with changing languages, operating systems and implementations, too.

For example the Common Lisp standard does not say anything about how an executable can be created. Maxima surely want s to do that. There are mow also libraries, which provide common interfaces for a bunch of general cases, though.

I write a lot of CL, and it’s reasonably easy to write standard-conforming code that just works across multiple implementations and, if you need something not standardized like sockets, TLS, or threads, there are fairly high-quality and “standard” portability libraries that make it easy to avoid reader conditionals most of the time.

The not-really-breaking change is not actually related to the version number. There is approximately 0% chance that somebody depends on the presence of that symbol in features. And there have been more actually noticeable compatibility changes with minor version bumps.

True, and a reason to applaud the changelog: it lists a potential breakage just because the is, well, a potential for breakage.

Yes, in reality, I'd be amazed to find code that actually breaks.

Reply on news.ycombinator.com