Re: Problem and solution: Patch for new "stats" command

[Philipp K. J. <ja...@ie...>]

> > The quotes are your addition. We don't expect them,
> > but we don't actively remove them. Maybe we should -
> > I admit that there is a user expectation that "there should
> > be quotes".
>
> Since 4.0 we support string variables. That means wherever a string
> is required in the input command, it is acceptable to provide
> a string constant, a string variable, or a string-valued function.
>
> So
>   A = "mydata"
>   stats "file.dat" using 1 variable=A
>
> must expand A to find "mydata", not use it as an unmarked constant.
> All strings should be parsed using the routine try_to_get_string(),
> which handles the three cases.
> Also, normal commands do not use = signs.

Good point on the string variable issue - I did not
think of that. 

There is a reason for the equality sign, though:
it indicates that the next token is the prefix - 
because we have chosen to make the prefix
optional. The equality sign is a way of telling 
gnuplot that the next token is a prefix, not the
next keyword.

(I admit that the equality sign is unusual and I did
hesitate a little. But it does provide a simple solution
to this particular problem.)

I don't want to make the prefix mandatory. For
convenience, it seems that in many cases it won't
be needed.