What is a "special function"?

[johnro@microsoft.UUCP (John ROGERS)]

Hi!  Could someone please clarify something in the LRM for me?  I've
been looking at the definitions of all of the attributes, and I noticed
something for the first time.  At least 5 of the attributes are described as
"functions", but 1 of the attributes is described as a "special function".
The regular ones ('IMAGE, 'POS, 'PRED, 'SUCC, and 'VALUE) don't seem to be
much different from the "special" one ('VAL).  I haven't been able to
find anything in the LRM (or the index to the Rationale that I have)
on this.  So, can anyone tell me what a "special function" is?

If you'd like to look it up for yourself, the sections of the LRM are
3.5.5(7) and Annex A(48).

Thanks in advance,
-- 
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