I’m not looking to debate - just that it’s not obvious and I suspect the specific reasons why would be interesting to know about.

Thanks!

Mesa/Cedar also shares some ideas with the other workstation variants from Xerox PARC, namely Interlisp-D and Smalltalk, just based on a strong typed language for systems programming, with reference counting and a cycle collector.

The language itself compiles to bytecode, because Xerox PARC machines used bytecode with microcoded CPUs, whose interpreter was loaded on boot. So in a sense it was still native somehow.

The full OS was written in Mesa/Cedar, and everything was kind of exposed to the developers.

The shell is more like a REPL, where you can access all that functionality, meaning the public functions/procedures from dynamically loaded modules, interact with text selection from any application window, or execute actions on a selected window. And as REPL, it worked on structured data.

Basically similar to what Powershell offers, with its structured data, and ability to call any COM/UWP, .NE or plain DLLs libraries.

Then you could embedded objects into other objects and this the basis of the compound document architecture, basically the genesis for OLE in Windows and COM (COM is just the basic features which OLE is built upon, although more the OLE 2.0, the 1.0 was more complicated still).

The way Office works between applications and its inline editing of OLE documents can be found in Xerox PARC workstations, as Charles Simonyi brought Bravo ideas into Word, as one of Bravo creators.

Since Windows Vista, most new APIs are actually a mix of .NET and COM (now UWP), which expose a similar high level set of OS API (bare bones Win32 has hardly changed since XP days).

Now, many of these concepts can also be found in GNOME and KDE, however due to the way distributions get put together, it is hard to really provide such integrated developer experience across the whole stack.

And while REPL like shells do exist for UNIX clones, their adoption is a tiny blip when compared against traditional UNIX shells.

I take this as a joke. There is nothing modern-looking about it. Geeky, yes. Not designed for touch interface. Resembles Oberon, which I would not call modern, either. Maybe, we are not ready for it yet. Belongs in the future, then. (Or, more likely, in the past.)

To proper understand a book one has to read more than just the back cover overview.