I’ve written an (incomplete) Forth interpreter on top of kakscript. This was a rather complex effort, which still needs more documenting, and I would like some feedback as time permits (@mawww ?).
To use, clone and symlink under autoload (or use plug https://gitlab.com/kstr0k/kak-stkmach)
After loading as above, select a name and boot a stack machine (multiple machines, with different prefixes, can boot):
require-module stkmach
stkmach-boot ff # create stack machine 'ff'
buffer *debug* # output shown in *debug* by default
ff-eval 3 2 + . # a simple op
echo -debug %opt{ff_builtins} # show available words
ff-interact # interactive Forth-ish buffer, use <a-ret>
Forth is a stack-oriented language. This implementation can do
- RPN arithmetic:
ff-eval 3 2 + 4 * . # =20; '.' means print - loops:
ff-eval 10 0 do i . loop # i = current counter - define “words”:
ff-eval : sqr dup * \; # duplicate, square, terminate def with \;3 sqr sqr . # 81 # use def to square repeatedly
- drive Kakoune (extension):
ff-eval 10 0 do i '' %{echo -debug} .kak-eval-top loop
It also showcases kakscript intended and un-intended computability, and is a good way to benchmark the kakoune C++ implentation. I have found some expected, but also some surprising slowdowns.
As an extension to Forth, strings can be placed on the stack using an empty-string ('') command, and be operated on (.str+, .str=/.str<>)