Re: Assignment functions (patchset # 1774478)

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Ethan A Merritt wrote:
> On Wednesday 15 August 2007 00:40, plotter wrote:

> The space required to write it out once should be about the same either way.
> But yes, I can see that the earlier f(x)=assign("var",expression)
> makes it much easier to re-use the definition concisely in multiple plot
> commands. 

Maybe, instead of inventing more new syntax, we should follow 
established C syntax a little further, e.g. implement the comma operator 
and the "each assignment is an expression, too" idea.  E.g. an averaging 
filter could be expressed as:

	using 1:(N = N + 1, sum = sum + $2, sum / N)

or even

	using 1:((sum += $2)/++n)

> It would be very easy to move the assignment evaluation to the beginning
> of the per-line processing rather than the end.  But then it becomes a
> problem what to do if the data line turns out to have missing or invalid
> entries. The earlier variant already suffers from this (see below).
> I'm open to suggestions here.

Honestly, I think this whole idea is going in the wrong direction. 
We're straying awfully far from the "one tool <--> one task" approch of 
Unix tradition here.  gnuplot is a plotting program, not a substitute 
for awk, Perl or Excel.  I'd prefer it if we left generic data 
processing to generic tools designed for the job.

And even if we're going to do this, the using specification is not 
really the right place to do it in.  It should be moved to a separate 
command.