TEX' , . ... PLAIN TEX .. ... TEX , - ( \vbox, \vtop, \vcenter, \valign, \vadjust \insert). ... def { } , { } . ... abovewithdelims (, ). , -- : \def\toto{\abovewithdelims[.1pt]} : . ... hbox \toto \hbox , : \hbox to 3mm{\hfil$*$\hfil}, \hbox to 10mm{$\hfil\circ\hfil$}, \hbox{\ \TeX\ }, .. plain \cleaders \xleaders, . ... 104 \newbox TEX 256 , \box0,...,\box256. , .., , , \newbox\toto, - \toto, , \setbox \toto: \setbox\toto=\hbox{...} \toto , \box\toto, \copy\toto, , \unhbox\toto, \unvbox\toto . ...