Re: typo injected an undeclared function into the name space ?

[<pl...@pi...>]

On 15/01/16 17:40, Ethan A Merritt wrote:
> On Friday, 15 January, 2016 11:38:01 pl...@pi... wrote:
>
>  > Hi ,
>
>  >
>
>  > I accidentally forgot a * operator when plotting a function. This seems
>
>  > to have injected an udefined fn into the name space
>
>  >
>
>  >
>
>  > twopi=2*pi
>
>  >
>
>  > gnuplot> plot datafile" u ($1/365.25+1970):2 w l, cos (twopi(x)/p3) +0.05
>
>  > undefined function: twopi
>
>  >
>
>  > User-Defined Functions:
>
>  > cos1(x)=a1*cos(twopi*(x-phi1)/p1)
>
>  > cos2(x)=a2*cos(twopi*(x-phi2)/p2)
>
>  > cos3(x)=a3*cos(twopi*(x-phi3)/p3)
>
>  > triple(x)=c+cos3(x)
>
>  > twopi is undefined
>
>  >
>
>  >
>
>  > gnuplot> print twopi
>
>  > 6.28318530717959
>
>  >
>
>  >
>
>  > Now it won't stop crapping on about "twopi is undefined", even though I
>
>  > have plotted something else and make no reference to it.
>
>  >
>
>  >
>
>  > All I can find to clear it is to quit gnuplot.
>
>  >
>
>  > Has this , as it seems, injected an undeclared function into the name
>
>  > space ?
>
>  >
>
>  > How to clear it more elegantly, is this a bug?
>
> There is currently no way to clear or delete any user-provided function.
>
> That is true for your well-defined functions as well as your undefined
>
> function. The "undefine FOO" command only looks for FOO as a variable
>
> name not as a function name.
>
> If you want to reset the entire namespace you can use "reset session".
>
> Of course that will clear everything, not just the undefined function.
>
> Ethan
>

Thanks Ethan,

the main point was, is this a bug?

how did I manage to register an undefined function simply by trying to ( 
accidentally ) use it in a plot command?

How does that become a function definition, right or wrong ?

Thanks.