- The concept of pushing/popping things onto/off the stack is a relatively straightforward programming model when done consistently
One of the old competitors to the likes of UEFI and uBoot is OpenFirmware (also known as OpenBoot), for which the primary UI is a Forth shell; OpenFirmware was the BIOS equivalent for Sun's SPARC workstations/servers (and still is for Oracle's/Fujistu's SPARC servers, last I checked) and most POWER hardware (including "New World" PowerPC Macs), among others. About the most delightful pre-boot environment I've used; it's a shame it didn't catch on in the x86 or ARM space.
In some ways it is even more abstraction-friendly than C because of how easy it is to manipulate functions or redefine its own interpreter/compiler. There was a nice example of a Tiny C compiler written in Forth by Marcel Hendrix posted to comp.lang.forth, with a Forth-defined VM as target. I posted a story about it at https://news.ycombinator.com/item?id=23455548
The big problem with Forth is software reliability: ad-hoc Forth code is hard to reason about in any generality. Languages like Factor show that dialects of Forth can be much better in this regard.
I got into Forth recently - using Gnu Forth - but got bogged down at my inability to do graphics. There are hardly any Forth programming videos of any kind online, besides the "101" kind, but I found one by a guy who managed to get graphics/windows going, I think with GForth. (Can't find it on youtube now.) Looked mega-complicated. So lately back into Tcl/Tk, which also satisfies my "bizarre, powerful and very cool language" itch but actually makes graphics/windows super-easy. I do think Forth is awesome though!
After getting into Forth I got into PostScript, which does have most of the Forth fun/freedom taken out of it. It's not usable for GUI-type programming is it?
This is (the now pedagogically famous) JonesForth. It's ~2000 lines of HEAVILY commented assembly, and at then you have everything you need to start writing a fully functional Forth+standard library (which is done in jonesforth.f in a ~1800 lines of heavily commented forth). That's not even as tiny as forth can be, and it gives you a lowish level language that is as/more modifiable and extensible as any Lisp.
There is basically no faster way to get from bare metal to a comfortable humane and interactive (so you can write more stuff) computing environment than writing a forth.
