Re: User selectable lower array bound?

[Paul van Delst <paul.vandelst(at)noaa.gov>]

Martin Schultz wrote:
> 
> Marc Schellens <m_schellens@hotmail.com> writes:
> 
> > Ahem:
> >
> > pro push,list,elem
> > if n_elements(list) eq 0 then list=[elem] else list=[list, elem]
> > end
> >
> > cheers,
> > marc
> 
> Won't work if elem is an array ;-( 

For rank-1 arrays, shur it will (Can lists, as defined by JD's Perl description be other
than rank-1?) I do it all the time. Except that I would do:

  if n_elements(list) eq 0 then list=elem else list=[list, elem]

For 2-D arrays you would have to check for conformability in your own code but that's also
easy to do. 4 or 5-D arrays would be a problem because at some point IDL chucks a nervous
wobbly when you try to do stuff like:

list = [[[[list]]],[[[elem]]]]

or somesuch sort of thing (i.e. too many "[]"'s). I think Craig Markwardt posted something
about this once.

> And if elem is a structure you will soon need something like
> Relax_StructAssign...

Shur, but I thought the whole point of something like Marc's push procedure was to
eliminate all the nasty details from the user (be they 2-d array or structure details),
i.e. it doesn the conformability check or the relaxed structure assignment?

paulv

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