+ 17 => array(# Internal variables with numeric values
+ 'ahangle','ahlength','bboxmargin','charcode','day','defaultcolormodel',
+ 'defaultpen','defaultscale','dotlabeldiam','hour','labeloffset',
+ 'linecap','linejoin','minute','miterlimit','month','mpprocset',
+ 'pausing','prologues','restoreclipcolor','showstopping','time',
+ 'tracingcapsules','tracingchoices','tracingcommands','tracingequations',
+ 'tracinglostchars','tracingmacros','tracingonline','tracingoutput',
+ 'tracingrestores','tracingspecs','tracingstats','tracingtitles',
+ 'troffmode','truecorners','warningcheck','year'
+ ),
+ 18 => array(# Internal string variables
+ 'filenametemplate','jobname','outputformat','outputtemplate'
+ ),
+ 19 => array(# other predefined variables
+ 'background','currentpen','currentpicture','cuttings','defaultfont',
+ 'extra_beginfig','extra_endfig'
+ ),
+ 20 => array(# predefined constants
+ 'beveled','black','blue','bp','butt','cc','cm','dd','ditto','down',
+ 'epsilon','evenly','EOF','false','fullcircle','green','halfcircle',
+ 'identity','left','mitered','mm','mpversion','nullpen','nullpicture',
+ 'origin','pc','pencircle','pensquare','pt','quartercircle','red',
+ 'right','rounded','squared','true','unitsquare','up','white',
+ 'withdots'
+ )
+ ),
+ 'SYMBOLS' => array(
+ '&',':=','=','+','-','*','**','/','++','+-+','<','>','>=','<=','<>',
+ '#@','@','@#'
+ ),