fluke8050a-forth VS able-forth

Here's a bunch of FORTH code for an embedded system application, where I built a replacement graphical LCD display for a Fluke multimeter. While I don't hold this up as a great example of proper style, it was my first non-trivial chunk of FORTH code.

This is more advanced than the common Forth struct implementation example but this is real Able Forth code used at Merj. The Able Forth code above gives you first-class types, vectors and records, and type extension (like inheritance). These words are the basis for other types.

Able Forth Optimized \ (smart postpone). Timed-wait is now available! The new now instruction provides access to a real-time nanosecond precision clock that is suitable for many tasks, including performance profiling. The default exception handler is now easy to replace at runtime.

Able Forth The bootstrap process is fully automated and easy to customize, making it simpler than ever to create a custom Forth system. A new create does implementation inspired by cmForth. A defer is implementation that more closely follows the standard. A smarter alias implementation guarantees aliases behave as expected in all cases. depth and reset instructions for retrieving stack depths and resetting execution. All signalled exceptions are trapped and reported by default.

Of course, there are many more use-cases. What surprised me is how simple it is to implement unwind protect in Forth (here implemented in Able Forth) and that I've never seen it implemented before :-).

I would consider adding Able Forth to the list. The Able Forth compiler targets the AbleVM, but in every other respect, it's a native code compiler (there's no reason Able Forth couldn't be made to emit native code for a physical machine). The default AbleVM core was designed to make the Able Forth compiler simple; it implements a 0-operand dual-stack virtual machine with ample general-purpose and base+offset address registers. Able is open source, in production use and under active development. If you decide it's interesting and you have any questions we're here to help.

While not exactly that, Able Forth works this way; more for simplicity than for efficiency. In Able Forth, there is no separate interpreter. Code entered to be executed immediately -- what we call evaluated -- is compiled into an evaluation buffer and a dynamic call is to the beginning of this buffer is performed. Primitives are implemented as compiling words that emit their required instructions, meaning that the code generated will be executed at full speed.