(j3.2006) [Third thoughts about DIM arguments]

[Malcolm Cohen]

Bill Long wrote:
> It looks like we're consistent in having "omitted" mean "does not appear".

Since my post was precisely about the several occurrences which are not 
consistent with that, this is an astonishing claim, and is rebutted by my post 
which was:

>> However, in the context of optional dummy arguments, "omitted" absolutely has 
>> to mean "not present".  It would be a serious violation of the design 
>> principles of optional dummy arguments to draw a distinction between 
>> textually not present and textually present but runtimely not present.  I 
>> agree that "omitted" is a poor choice of word though since it is more often 
>> used to mean "does not appear" syntactically.

This is an optional fundamental principle: presence of dummy arguments is 
transitive.

The intrinsic functions in question describe the DIM argument as optional with 
no prohibition against it the actual argument being an optional dummy argument. 
That means it is permitted to pass an optional dummy argument to those 
functions, and that passing an absent one is treated the same as it being 
textually not present - because that is how optional dummy arguments work!

Cheers,
-- 
................................Malcolm Cohen, Nihon NAG, Tokyo.