3/8/2026 at 10:54:37 AM
In my grad school days, a couple of decades ago, I had written a library for my own use to facilitate chaining of different kinds of numeric operations on data vectors and sequences. Essentially, for a very simple form of deforestation [0,1], equipped with intermediate buffers to facilitate SIMD.GCC, surprisingly, was quite good at generating SIMD code from it and eliminating temporary data vectors. GCC was even quite good at explaining why it didn't emit SIMD that I wanted it to emit. Much to my surprise GCC was better in this regard than Clang. From what I had read about Clang at that time, it should have been the otherway round. The error messages were better too (wonders of competition).
I quite liked it. It was a loads of fun. I would however be wary of using it in anger.
The problem is, this sublanguage feels more like a dynamically typed language where errors would be thrown deep in the instantiation chain when it ultimately failed to instantiate.
There was no type-system to guide you ahead-of-time that what you are trying to do would eventually fail to instantiate.
The code got lost when Bitbucket stopped it's support for Mercurial. I still likely have it somewhere in my old files.
Later I wanted to rewrite this in D but never started (thrown out of my university because I graduated).
[0] https://en.wikipedia.org/wiki/Deforestation_(computer_scienc...
by srean
3/8/2026 at 11:35:29 AM
It is pretty well known that C++ templates really are dynamically typed, it's compile time duck typing.What you did sounds like Eigen, which probably takes expression templates much further than you did due to the long time it's been around. It is weirdly absent from its documentation, but Eigen does have explicit SIMD support for several architectures and SIMD instruction sets. https://libeigen.gitlab.io/
by ahartmetz
3/8/2026 at 11:41:46 AM
Yes am familiar with Eigen. And yes I am/was that lunatic you mention in your other comment.This thing I wrote, predated Eigen (by a few years, I think) had a better support for pipelines and dataflow oriented programming (at least in the context of what I needed) than Eigen. It was more like itertools, functools of Python. Likely older than Eigen but positively after Blitz++ because I remember studying Blitz++ code.
Unlike Eigen, mine had no explicit support for intrinsics, for that I relied on a smart enough compiler, GCC was surprisingly good.
Too bad MSVC was quite bad at optimising and inlining away to the expression trees that Eigen (and mine) generated.
by srean
3/9/2026 at 5:09:38 PM
[dead]by tug2024