-(types.ps) run
-(reader.ps) run
-(printer.ps) run
+/runlibfile where { pop }{ /runlibfile { run } def } ifelse %
+(types.ps) runlibfile
+(reader.ps) runlibfile
+(printer.ps) runlibfile
% read
/_readline { print flush (%stdin) (r) file 99 string readline } def