cfl.txt

编译原理课程试验

编译原理实验文法——LR文法
一、说明语句
    1.	P→D        (p.at=d.at)
    2.	D→DM        (d.at=m.at)
    3.	D→M       (d.at=m.at)
    4.	M→id:I;      (fill(entry(id),i.at);m.at=i.at))
    5.	M→id(){DL}
    6.	I→int        (i.at=int)

二、表达式
    7.	E→E+T       (e.place=newtemp;gen(+,e1.place,t.place,e.place))
    8.	E→T        (e.place=t.place)
    9.	T→T*F       (t.place=newtemp;gen(*,t1.place,f.place,t.place))
    10.	T→F      (t.place=f.place)
    11.	F→id        (f.place=entry(id))
    12.	F→(E)        (gen(=,e.place,_,f.place))
    13.	F→constant (常数)    (f.place=entry(constant))

三、布尔表达式
    14.	B→B and C   (b.place=newtemp;gen(and,b1.place,c.place,b.place))
    15.	B→C        (b.place=c.place)
    16.	C→(B)      (gen(=,e.place,_,f.place))
    17.	C→E<E      (e.place=newtemp;gen(<,e1.place,e2.place,c.place))
    18.	C→true    (gen(=,'1',_,e.place))

四、句法
    19.	L→LS
    20.	L→S
    21.	S→{L}
    22.	S→id=E;       (gen(=,e.place,_,entry(id)))
    23.	S→while(B) S
    24.	S→if(B) S      
    25.	S→if(B) S else S