Re: Meaning of trange in parametric plots

[Ethan A M. <sf...@us...>]

On Thursday, March 07, 2013 11:41:44 am Dima Kogan wrote:
> Hans-Bernhard Bröker <HBB...@t-...> writes:
> 
> > On 06.03.2013 22:52, Dima Kogan wrote:
> >> Hans-Bernhard Bröker <HBB...@t-...> writes:
> >
> >>> They can't be, because there is nu such thing as a parametric plot from
> >>> a data file.  Parametric mode is a property of function plots.
> >
> >> Hmmm. You're right; this doesn't make sense. In that case, should
> >> gnuplot be plotting anything at all? Would it be more appropriate for it
> >> to simply emit and error message and refuse to plot anything?
> >
> > What on earth should it do _that_ for?  There's nothing wrong there. 
> > Having parametric mode and trange set while you doing a pure data plot 
> > is just _irrelevant_, but not wrong.
> 
> In cases when the user is trying to do something that doesn't make sense
> it's far better to throw an error (or warning) than to silently do the
> wrong thing. I am now clear on why 'set parametric' is not connected to
> plots from files, so I wouldn't benefit from an error message here, but
> a new user may. That's all I was suggesting.

There is not, and should not be, any warning for setting a parameter in
advance of using it.  E.g. there's nothing odd about a script that selects 
a palette but doesn't use it until several plots later.  In general there's
nothing odd about loading a file containing your preferred defaults even
if only some of them apply to the plot you are about to make.
Choosing a customized set of default ranges is simply an example of this.

	Ethan