link-from:header — ordinary primitive
FORTH
LINK>
( lfa -- cfa )(
)
;
p4:"link-from";
converts a pointer to the link-field (LFA) to point then to the corresponding code-field (CFA)
BEWARE: this one does not care about SYNONYMs and it is the only way to get at the data of a SYNONYM. Therefore, if you have a synonym called A for an old word B then there is a different result using "NAME>" on an A-nfa or using "N>LINK LINK>" since the first "NAME>" will return the xt of B while the latter will return the xt of A - but executing an xt of A is an error and it will THROW
this difference is intentional to allow knowledgable persons to do weird things looking around in the dictionary. The forth standard words will not give you much of a chance to get hold of the nfa of a SYNONYM word anyway - asking FIND for a word A will return the execution token of B immediatly and "NAME>" on that one lead to the nfa of B and not that of A.