out of date documentation

[Dirk Herrmann]

Hello documentation folks:

I read in the documentation (on glug):

  Macro: int SCM_NIMP (SCM x) 
       Return non-zero iff x is a non-immediate object. This is the exact
       complement of SCM_IMP, above. 

       You must use this macro before calling a finer-grained predicate to
       determine x's type. For example, to see if x is a pair, you must
       write: 

         SCM_NIMP (x) && SCM_CONSP (x)

       This is because Guile stores typing information for non-immediate
       values in their cells, rather than in the SCM value itself; thus,
       you must determine whether x refers to a cell before looking inside
       it. 

       This is somewhat of a pity, because it means that the programmer
       needs to know which types Guile implements as immediates vs.
       non-immediates.  There are (possibly better) representations in
       which SCM_CONSP can be self-sufficient. The immediate type
       predicates do not suffer from this weakness. 

This information is out of date, since AFAIK most (all?) macro type
predicates in guile do the !SCM_IMP test by themselves.

A more detailed discussion of the recent approach to low-level type
handling in guile can be found in the file guile-core/doc/api.txt, which I
have written at the time when we decided to switch to the new mechanism.  
Thus, I will be glad to answer any questions or to clarify if necessary.  
Otherwise I think the text can mostly be used as it is, despite some
improvements to my english and the texinfo markup.

Best regards,
Dirk Herrmann