This is MetaPost, Version 0.641 (Web2C 7.2) (mem=mp.little 1999.10.23)  23 OCT 1999 21:08
**&mp.little x.mp
(x.mp
>> syntax.error
! Isolated expression.
<to be read again> 
                   addto
draw->addto
           .currentpicture.if.picture(EXPR0):also(EXPR0)else:doublepath(EXPR...
<to be read again> 
                   ;
x.mp:4: draw fullcircle scaled 1cm;
                                   
? 
! Emergency stop.
<to be read again> 
                   addto
draw->addto
           .currentpicture.if.picture(EXPR0):also(EXPR0)else:doublepath(EXPR...
<to be read again> 
                   ;
x.mp:4: draw fullcircle scaled 1cm;
                                   
End of file on the terminal!