1.已知文法:
S->a|^|(T)
T->T,S|S
分析句型(T,(^,a)),求全部的短语、直接短语和句柄。
S->(T)->(T,S)->(T,(T))->(T,(T,S))->(T,(S,S))->(T,(^,S))->(T,(^,a))
直接短语:^ a
句柄:^
短语:^ a ^,a (^,a) T,(^,a) (T,(^,a))
2.构造上下文无关文法,描述语言:
(1){anbn|n>=0}
(2){ambn|m>=n>=0}
(3) if语句
(1)G[S]:S->aSb|ab|ε
(2)G[S]:S->aSb|ab|a|ε
(3)G[S]:S->if(条件){(执行语句)}S|if(条件){(执行语句)}else{(执行语句)}