Collapse OS – Why Forth?
If I had to put my finger on why Forth is hard for most programmers, it's like this: the structured program theorem suggests using sequence, selection, and iteration to control program logic. Assembly code on hardware architectures will assign all meaning sequence-relative, late-binding the selection and iteration. Forth doubles down on this sequence-first  approach through a more versatile assignment mode(the stack) while only minimally  accommodating the other two. That makes it easy to implement, while not explicitly addressing expressability.<p>Forth written "flat" with shallow data stack usage is assembly by another name, a wrapper for load-and-store; Forth that does everything with intricate stack manipulation is a source of endless puzzles since it quickly goes write-only.<p>But, like any good language with meta expression capabilities, you can work your way up towards complex constructs in Forth, and write words that enforce whatever conceptual boundaries are needed and thus check your work and use the system as a compiler. That's what breaks Forth away from being a simple macro-assembler. But you have to write it in that direction, and design the system that makes sense for the task from the very beginning. That falls into an unacceptable trade-off really easily in our current world, where the majority of developers are relatively inexperienced consumers of innumerable dependencies.