> namespace

Nod. I fuzzily recall being told yeas ago of ITA Software struggling to even build their own CL code. Reader-defined-symbol load-order conflict hell, as I recall. And that was just a core engine, embedded in a sea of Java.

> second class citizens

I too wish something like Kernel[1] had been pursued. Kernel languages continue to be explored, so perhaps someday. Someday capped by AI/VR/whatever meaning "it might have been nice to have back then, but old-style languages just aren't how we do 'software' anymore".

> detailed documentation covering all the design criteria and coding decisions

As in manufacturing, inadequate docs can have both short and long-term catastrophic and drag impacts... but our tooling is really bad, high-burden, so we've unhappy tradeoffs to make in practice.

Though, I just saw a pull request go by, adding a nice function to a popular public api. The review requested 'please add a sentence saying what it does.' :)

So, yeah. Capturing design motivation is a thing, and software doesn't seem a leader among industries there.

> enable future generations to build upon what has been done.

Early python had a largely-unused abstraction available, of objects carrying C pointers, so C programs/libraries could be pulled together at runtime. In an alternate timeline, with only slightly different choices, instead of monolithic C libraries, there might have been rich ecology. :/ The failure to widely adopt multiple dispatch seems another one of these "and thus we doomed those who followed us to pain and toil, and society to the loss of all they might have contributed had they not been thus crippled".

> To understand a piece of Lisp code [...struggle]

This one I don't quite buy. Java's "better for industry to shackle developers to keep them hot swappable", yes, regrettably. But an inherent struggle to read? That's always seemed to me more an instance of the IDE/tooling-vs-language-mismatch argument. "You're community uses too many little files (because it's awkward in my favorite editor)." "You're language shouldn't have permitted unicode for identifiers (because I don't know how to type it, and my email program doesn't like it)." CL in vi, yuck. CL in Lisp Machine emacs... was like vscode or eclipse, for in many ways a nicer language, that ran everything down to metal. Though one can perhaps push this argument too far, as with smalltalk image-based "we don't need no source files" culture. Or it becomes a "with a sufficiently smart AI-complete refactoring IDE, even this code base becomes maintainable".

But "trickily" written code, yes. Or more generally, just crufty. Perhaps that's another of those historical shifts. More elbow room now to prioritize maintenance: performance less of a dominating concern; more development not having the flavor of small-team hackathon/death-march/spike-into-production. And despite the "more eyeballs" open-source argument perhaps being over stated, I'd guess the ratio of readers to writers has increased by an order of magnitude or two or more, at least for popular open source. There are just so very many more programmers. The idea that 'programming languages are for communicating among humans as much as with computers' came from the lisp community. But there's also "enough rope to hang yourself; enough power to shoot yourself in the foot; some people just shouldn't be allowed firearms (or pottery); safety interlocks and guards help you keep your fingers attached".

One perspective on T(est)DD I like, is it allows you to shift around ease of change - to shape the 'change requires more overhead' vs 'change requires less thinking to do safely' tradeoff over your code space. Things nailed down by tests, are harder to change (the tests need updating too), but make surrounded things easier to change, by reducing the need to maintain correctness of transformation, and simplifying debugging of the inevitable failure to do so. It's puzzled me that the TDD community hasn't talked more about test lifecycle - the dance of adding, expanding, updating, and pruning tests. Much CL code and culture predated testing culture. TDD (easy refactoring) plus insanely rich and concise languages (plus powerful tooling) seems a largely unexplored but intriguing area of language design space. Sort of haskell/idris T(ype)DD and T(est)DD, with an IDE able to make even dense APL transparent, for some language with richer type, runtime, and syntax systems.

Looking back at CL, and thinking "like <current language>, just a bit different", one can miss how much has changed since. Which hides how much change is available and incoming. 1950's programs each had their own languages, because using a "high-level" language was implausibly heavy. No one thinks of using assembly for web dev. Cloud has only started to impact language design. And mostly in a "ok, we'd really have to deal with that, but don't, because everyone has build farms". There's https://github.com/StanfordSNR/gg 'compile the linux kernel cold-cache in a thrice for a nickle'. Golang may be the last major language where single-core cold-cache offline compilation performance was a language design priority. Nix would be silly without having internet, but we do, so we can have fun. What it means to have a language and its ecosystem has looked very different in the past, and can look very different in the future. Even before mixing in ML "please apply this behavior spec to this language-or-dsl substrate, validated with this more-conservatively-handled test suite, and keep it under a buck, and be done by the time I finish sneezing". There's so much potential fun. And potential to impact society. I just hope we don't piss away decades getting there.

[1] https://web.cs.wpi.edu/~jshutt/kernel.html