Jim,

> I've got a few of questions.  People have suggested using '.' delimiters
> to build full variable names (path names).  Since '.' has historically
> been a legal part of a variable name, would it perhaps be better to use
> ':', '\', or '|' instead?  And why is '/' forbidden?  Is it used
> internally somehow, or reserved for just such a time as this?

There is currently a problem with using "." for such a separator,
causing problems using DAP protocol to access data from a variable with
a name such as "x.y", as described in this issue:

  https://bugtracking.unidata.ucar.edu/browse/NCF-178

Both netCDF-3 and netCDF-4 permit any character (including UTF-8-encoded
Unicode characters) in names, except for '/'.  The netCDF-4 public API
already uses '/' in names returned or input to the functions
nc_inq_grpname_full() and nc_inq_grp_full_ncid(), the same way it's used
in HDF5 or Unix file systems (which also forbid '/' in file names).

We've briefly discussed using '/' for emulating groups in classic-format
files, with the library parsing and interpreting names containing '/'
appropriately, but we haven't yet determined how practical this would
be, or whether it could be implemented in a totally backward-compatible
way.

--Russ
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