S- attribute grammars, Only have synthesized attributes L- attribute grammars, for every production A→XX2…Xn, each attribute is a synthesized attribute or is a nherited attribute of X (1≤≤n), and the nherited attribute of X (1sisn) depends on the Inherited attribute of a or depends on the attributes ofX, x 2 in every semantics ruleS－ attribute grammars，Only have synthesized attributes L－ attribute grammars， for every production A→X1X2…Xn，each attribute is a synthesized attribute or is a Inherited attribute of Xj （1≤j≤n）,and the Inherited attribute of Xj （1≤j≤n） depends on the Inherited attribute of A or depends on the attributes of X1，X2，…， Xj-1 in every semantics rule