This is a threaded code emulator written in ANS Forth.

The purpose of it was to allow the use of backtracking on
Forth systems that do not allow return stack manipulations.

tcf.fth     -- the Threaded Code Emulator
tcf-num.fth -- number conversion for it
needs.fth   -- the word needs
ansitst.fth -- ANS Forth testing suite that I used to check that tc-emu works

The word EVALUATE does not work.
tc-emu reuses the existing words like >IN and WORD, but defines
its own INTERPRET.
Now, in ANS Forth there is no way to establish a new input source
and run something different from EVALUATE .
It is still possible to write a kludge that overwrites the
string being interpreted (provided that its length is greater than 0),
but it is left as an exercise to the user.

Another unpleasant thing has been inability to use ['] EXIT EXECUTE
to exit a definition. I could make up a workaround by using a flag,
but it's surely ugly.

The VOCABULARY _TC-FORTH_ contains all redefined words.
(the Forth-83-compliant version of VOCABULARY may be found in the
ANS Forth Rationale).

I considered hiding this, but did not finish the code.
So, the vocabulary is not invisible... and probably will never be.

Good luck,
Michael Gassanenko
mlg @ forth . org