typo injected an undeclared function into the name space ?

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

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?

Peter.