On Sat, 24 May 2008, Sven Schreiber wrote:
[ first, about cating 1x1 matrices to scalars, to which I'll reply
later, then... ]
> > BTW, on various occasions I noticed that arithmetic
> > expressions cannot always be used in place of simple
> > variables. But sometimes it does seem to work. Is there some
> > rule when it should work, or is it sheer luck when it does?
> In general, arbitrary arithmetic should work for arguments to
> built-in functions (or user-defined functions for that
> matter), while it's not very likely to work for arguments to
> straight "commands".
In principle I think I understand, but I'm not sure the
demarcation between commands and functions is very clear in
gretl. What would that 'pvalue' thing be for example?
For the most part the distinction is pretty clear: a function is
something where all the arguments are wrapped in parentheses and
separated by commas, and a command is everything else. But there
are a few hybrid cases, and "pvalue" is one such. Since we have a
perfectly good pvalue function with the same semantics, we
implement the "command" form by composing and executing a call to
"genr"; this gives more flexibility on the form of the arguments.