I've fixed my Forth so RP0 , a user variable, now points to the initial address of the return stack and RP@ returns the address of the top item on the return stack.

With this change I've tried a variation on an idea from M.L.Gassanenko. I wrote a generic stack word, STACK , which iterates through ...

RP0 and SP0 are user variables which point to the initial address of their respective stacks. On multitasking systems, each task has its own set of stacks; therefore, RP0 returns a unique address for each task. The same for SP0 . These words, along with RP@ and SP@ can also be used to write ...

My Forth, a Forth-83 Standard Forth, has the word SP@ . In "Starting FORTH" SP@ is named 'S .

The stack pointer is fetched by the word 'S (pronounced tick-S).
Since 'S provides the address of the top stack location, the phrase
'S @
fetches the contents of the top of the stack. This operation, of ...

Fleet Forth dictionary and vocabularies.
The structures:
There is only one Dictionary in Fleet Forth. As is true with the Forth Leo Brodie discusses in "Starting Forth", Fleet Forth's vocabularies are independently linked lists which weave through the dictionary.

Each dictionary entry consists of ...

I know Pascal-type strings... I've worked with Turbo-Pascal way before I learned C in the 80's... :P
I just think that C-type strings are WAY easier to work with. And are not limited in length. I really do not understand why Charles Moore chose Pascal-type strings over C-type.
Forth's memory ...

I have streamlined the code for Fleet Forth's WITH-WORDS

: WITH-WORDS ( -- NFA )
CONTEXT @
AHEAD
BEGIN
DUP R@ 2>R L>NAME CO R>
CS-SWAP THEN
@ DUP 0=
UNTIL
R> 2DROP ;

The only test to break out of the loop in WITH-WORDS is a test to see if there are no more words in the CONTEXT ...

Some Forths have a word .S which non-destructively displays the contents of the data stack. Fleet Forth also has the word .RS to non-destructively display the contents of the return stack. This word is used in one of the step display words in Fleet Forth's TRACE and in Fleet Forth's (ERR) , an ...

... my own preference would be...

?EXIT \ pop top of stack. exit if true.
?0EXIT \ pop top of stack. exit if false.
... because they both conditionally execute based on TOS (which gets popped), and that's a scenario I associate with the question mark. And the 0 gets added if you wanna reverse ...

One of the words from the Forth-83 Standard in the UNCONTROLLED REFERENCE WORDS section is ;S . It is used to stop interpretation of a block. On some Forth's it can be defined as an alias for EXIT , the runtime compiled by ; (semicolon). This will not work with my Forth. My Forth's INTERPRET ...

Fleet Forth has the word DONE? which checks if a key was pressed. If no key was pressed DONE? returns FALSE . If the RUN/STOP key was pressed DONE? returns TRUE . If any other key was pressed DONE? waits for a key press and returns TRUE if the RUN/STOP key is pressed and FALSE otherwise.
I added ...

: levels-back r> drop 0 do r> drop loop ;
I think that code is very, very non-portable, because many (pretty much all?) vintage FORTHs keep the loop index and limit on the return stack and would choke on this. The allegation that Tali doesn't choke is mildly impressive.
This version of LEVELS ...

As I mentioned previously my own Forth, as well as Scott Ballantyne's Blazin' Forth, also adjusts the limit and index of a DO LOOP to take advantage of a branch on overflow; however, Scott Ballantyne's Blazin' Forth adds $8000 to the limit and subtracts this adjusted limit from the index. The ...

I was not satisfied with two names in the Fleet Forth kernel.
The first name, 'STREAM , implies the address of the input stream. 'STREAM actually returns the address and count.
From the Forth-83 Standard.

The input stream extends from the offset value of >IN to the
size of the input stream ...

Not sure if this belongs in the thread "CS-101 problems and their FORTH solutions" or if I should have started a new Forth and mathematics thread. This example involves repetends. It was easier to program than to explain. After the basic introduction I attempt a top down explanation of the code ...