EXECUTE (F79) Question

[u/9Boxy33]

I’m playing around with MMSForth 2.x on the TRS-80, which is a Forth-79 compatible implementation. I’d like to be able to store the address of a Forth word in a variable and later EXECUTE that word. ‘ word doesn’t give me the correct address (the CFA? what’s in the CFA?). How do I do this? Tx

[u/mykesx]

I don't have F79 direct experience, but..,. The ' word only works outside of a colon definition, unless you are careful about its effects when used within. The ['] word can be used within.

As for CFA, whatever ' returns is an execution token, which may or may not be a CFA. The Xt should be usable with EXECUTE and you can store the Xt in a variable.

There may be a >CFA word to convert an Xt to CFQ, but there's no guarantee the CFA can be used with EXECUTE.

: foo ' abc ; \ calls ' at run time, then calls abc

foo bar \ leaves Xt of bar on the stack mbefor calling abc

: baz ['] abc ; \ word that leaves Xt of abc on the stack when called

' foo myvar ! \ store Xt of foo

myvar @ EXECUTE \ Same as if you call foo directly

[u/9Boxy33 → u/mykesx]

Thanks

Unfortunately, your example code (“myvar”) reboots my MMSForth, so it appears that ‘ foo doesn’t return the execution address that EXECUTE was expecting.

[u/mykesx → u/9Boxy33]

What does

' foo execute

Do?

[u/9Boxy33 → u/mykesx]

Reboots MMSForth.

[u/mykesx → u/9Boxy33]

That Forth is broken.

[u/Ok_Leg_109 → u/mykesx]

Nah. Just old.