Re: --nest for nested argument files

[Benjamin R. Haskell]

On Tue, 3 May 2011, Ole Tange wrote:

> On Tue, May 3, 2011 at 5:06 PM, Rhys Ulerich wrote:
> > > > Following a recent discussion on the list I have given some thought 
> > > > to making an option --nest.
> >
> > > My first thought was --multiply (as in multiply list 1 with list 2) 
> > > but I agree that --nest (as in nested for loops) is better.
> >
> > Hmm... along the lines of --multiply I'd have said --outer as in 
> > outer product.  You could then also have --inner as in inner product 
> > which would concatenate lines from multiple files prior to 
> > processing.
>
> I would like the option to be called something that people might 
> google for. I personally would never have googled for outer and inner. 
> I might have googled for multiply.
>
> Can we come up with an even better word? Maybe something already used 
> elsewhere?

My first thought was --cross (from cross product).  (Maybe --cartesian 
(from Cartesian product)?)

'--cross' has the disadvantage of being very overloaded (cross product, 
(a)cross different hosts, cross-compilation, etc.).  On the other hand, 
we're talking about software with the name 'parallel', so being 
unambiguous is obviously not priority #1... ;-)

Other preferable synonyms might be found on:
http://en.wikipedia.org/wiki/Direct_product


> > I'd think something called "--nest" would be handy for situations 
> > where one wants parallel to invoke parallel.
>
> Which is basically what --nest does:
>
>  parallel -a file1 parallel -a file2 -I {o} echo {} {o}
>
> will be the same as:
>
>  parallel --nest -a file1 -a file2 echo {1} {2}

But it's not actually nested, which seems misleading.

--
Best,
Ben