已知文法G=({A,T,S},{a,(,),@},P,S),其中P为: S→a|A|(T) T→T@S|S 判断文法G适用于LR(0)、SLR(1)、LALR(1) 还是LR(1)分析方法
时间: 2023-11-24 17:08:27 浏览: 112
首先,我们需要计算出文法G的所有项目集族。计算过程如下:
初始状态:
I0: S' → •S
通过S' → S,可以得到S的闭包:
I1: S' → S•
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
对于第一个项目S' → S•,由于S'不会再出现在任何产生式的左部,所以它没有任何后继的项目。对于其余的项目,我们需要根据它们的后继符号将它们进行归约或移进操作。
对于S → •a,它的后继符号是a,所以可以将其移进,得到:
I2: S → a•
对于S → •A,它的后继符号是A,因此需要将A的所有产生式加入到项目集中:
I3: S → A•
A → •a
A → •(T)
对于S → •(T),它的后继符号是(,因此需要将(加入到项目集中,并将(后面可能出现的所有符号加入到项目集中:
I4: S → (•T)
T → •T@S
T → •S
对于T → •T@S,它的后继符号是T,因此需要将T的所有产生式加入到项目集中:
I5: T → T•@S
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
对于T → •S,它的后继符号是$,因此需要将$加入到项目集中:
I6: T → S•
现在,我们已经得到了文法G的所有项目集族,如下:
I0:
S' → •S
I1:
S' → S•
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
I2:
S → a•
I3:
S → A•
A → •a
A → •(T)
I4:
S → (•T)
T → •T@S
T → •S
I5:
T → T•@S
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
I6:
T → S•
接下来,我们需要计算每个项目集的LR(0)、SLR(1)、LALR(1)和LR(1)闭包。由于项目集族较小,我们可以手动进行计算。
首先,根据LR(0)分析方法的定义,对于一个项目集I,其LR(0)闭包是包含I中所有可能的前缀的所有项目的集合。因此,对于I0,其LR(0)闭包为:
I0:
S' → •S
I1:
S' → S•
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
I2:
S → a•
I3:
S → A•
A → •a
A → •(T)
I4:
S → (•T)
T → •T@S
T → •S
I5:
T → T•@S
S → •a
S → •A
S → •(T)
T → •T@S
T → •S
I6:
T → S•
根据SLR(1)分析方法的定义,对于一个项目集I,其SLR(1)闭包是包含I中所有可能的前缀和跟在其后面的终结符的所有项目的集合。因此,对于I0,其SLR(1)闭包为:
I0:
S' → •S
[ $ ]
I1:
S' → S•
[ $ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
S → •(T)
[ $, a, ( ]
T → •T@S
[ $, a, ( ]
T → •S
[ $, a, ( ]
I2:
S → a•
[ $, a ]
I3:
S → A•
[ $, a, ( ]
A → •a
[ $, a, ( ]
A → •(T)
[ $, a, ( ]
I4:
S → (•T)
[ $, a, ( ]
T → •T@S
[ ) ]
T → •S
[ ) ]
I5:
T → T•@S
[ $, a, (, @ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
S → •(T)
[ $, a, ( ]
T → •T@S
[ $, a, (, @ ]
T → •S
[ $, a, (, @ ]
I6:
T → S•
[ $, a, (, @ ]
根据LALR(1)分析方法的定义,对于一个项目集I,其LALR(1)闭包是包含I中所有可能的前缀和跟在其后面的终结符以及跟在其后面的非终结符的所有项目的集合。因此,对于I0,其LALR(1)闭包为:
I0:
S' → •S
[ $ ]
I1:
S' → S•
[ $ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
S → •(T)
[ $, a, ( ]
T → •T@S
[ $, a, ( ]
[ $, a, (, @ ]
T → •S
[ $, a, ( ]
[ $, a, (, @ ]
I2:
S → a•
[ $, a ]
I3:
S → A•
[ $, a, ( ]
A → •a
[ $, a, ( ]
A → •(T)
[ $, a, ( ]
[ $, a, (, @ ]
I4:
S → (•T)
[ $, a, ( ]
T → •T@S
[ ), $ ]
[ ), $, a ]
[ ), $, a, ( ]
[ ), $, a, (, @ ]
T → •S
[ ), $ ]
[ ), $, a ]
[ ), $, a, ( ]
[ ), $, a, (, @ ]
I5:
T → T•@S
[ $, a, (, @ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
S → •(T)
[ $, a, ( ]
[ $, a, (, @ ]
T → •T@S
[ $, a, (, @ ]
T → •S
[ $, a, (, @ ]
I6:
T → S•
[ $, a, (, @ ]
根据LR(1)分析方法的定义,对于一个项目集I,其LR(1)闭包是包含I中所有可能的前缀、跟在其后面的终结符和非终结符以及跟在其后面的终结符和非终结符的所有项目的集合。因此,对于I0,其LR(1)闭包为:
I0:
S' → •S
[ $ ]
I1:
S' → S•
[ $ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
S → •(T)
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
T → •T@S
[ $, a, ( ]
[ $, a, (, @ ]
[ $, a, (, a ]
[ $, a, (, ), @ ]
T → •S
[ $, a, ( ]
[ $, a, (, @ ]
[ $, a, (, a ]
[ $, a, (, ), @ ]
I2:
S → a•
[ $, a ]
I3:
S → A•
[ $, a, ( ]
A → •a
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
A → •(T)
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
[ $, a, (, a, @ ]
[ $, a, (, ), @ ]
I4:
S → (•T)
[ $, a, ( ]
T → •T@S
[ ), $, a ]
[ ), $, a, ( ]
[ ), $, a, (, @ ]
[ ), $, a, ), @ ]
T → •S
[ ), $, a ]
[ ), $, a, ( ]
[ ), $, a, (, @ ]
[ ), $, a, ), @ ]
I5:
T → T•@S
[ $, a, (, @ ]
S → •a
[ $, a ]
S → •A
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
S → •(T)
[ $, a, ( ]
[ $, a, (, a ]
[ $, a, (, ) ]
[ $, a, (, a, @ ]
[ $, a, (, ), @ ]
T → •T@S
[ $, a, (, @ ]
[ $, a, (, a, @ ]
[ $, a, (, ), @ ]
T → •S
[ $, a, (, @ ]
[ $, a, (, a, @ ]
[ $, a, (, ), @ ]
I6:
T → S•
[ $, a, (, @ ]
[ $, a, ), @ ]
因此,我们可以得出结论:
- 文法G适用于LR(0)、SLR(1)、LALR(1)和LR(1)分析方法。
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