taolson
5 days ago
Fun fact I learned from a Func Prog podcast: the name Steel Bank is a play on it's origin as Carnegie-Mellon Common Lisp (Carnegie made his fortune in Steel, while Mellon did so with Banks):
p_l
5 days ago
There's another wordplay in the name.
Namely, that "SB" stands for "Sanely Bootstrappable" - something that the CMU Common Lisp was unable to do
jojohohanon
5 days ago
In my first job, grumpy Martin had as one of his many indispensable tasks, to build cmucl. (Itasoftware, one of the main lisp shops of the age)
guenthert
5 days ago
It is my understanding that easing bootstrap was the original motivation of the fork of CMU CL. I'm a bit confused about that, since CMU CL supports compilation to byte-code (which should make a port to a new architecture comparatively easy), a feature which was dropped in SBCL.
p_l
5 days ago
The sane bootstrap is not about porting to new architecture, but about building the compiler from source in the first place. CMU CL effectively requires that you use the same version of CMU CL to build it, IIRC, which in practice meant you had to first load the changes into older CMU CL image - overwriting core components, and then use that image to compile new version.
The difference with SBCL is that it can compile so long as you have any CL implementation that handles certain broad, but not complete, subset of ANSI CL.
It does it by being able to compile itself in sort-of sandboxed state hosted within another CL image, and then using that compiler to build itself, without requiring to modify the host compiler like CMU
As for the bytecode, as far as I recall CMU CL did not have bytecode compiler at all - it had evaluator option, which was indeed dropped for a long time from SBCL but was recently reintroduced, partially to support efforts such as porting Kandria [1] to Nintendo Switch
jhgb
5 days ago
> As for the bytecode, as far as I recall CMU CL did not have bytecode compiler at all
The byte code compilation option is described in CMUCL documentation, section 5.9 Byte Coded Compilation: https://cmucl.org/docs/cmu-user/html/Byte-Coded-Compilation....
p_l
4 days ago
Ah, with how cmucl was problematic to get running I never delved that deep. It indeed is not present in SBCL.
That said, as mentioned, it gave no real impact on bootstrappability nor portability
pfdietz
5 days ago
That's more of a backronym.