The third work syntax tree, phrases, phrases directly Handles

1. 1.   Known grammar:

S->a|^|(T)

T->T,S|S

Analysis sentence (T, (^, a)), find all phrases, phrases and handle directly.

推导:   s=>(T)=>(T,s)=>(T,(T))=>(T,(T,s))=>(T,(s,s))=>(T,(^,s))=>(T,(^,a))

Syntax tree:

 

All phrases:  (T, (^, A)); T, (^, A); (^, A); ^, A; ^; A  

Direct phrases:    ^; A    

Handle: ^

1. 2. The   configuration context-free grammar description language:

｛aⁿbⁿ|n>=0｝

｛a^mbⁿ|m>=n>=0｝

if statement

solution:

｛aⁿbⁿ|n>=0｝：

D -> aDb | ab | ε

｛a^mbⁿ|m>=n>=0｝：

E -> aEb | ab | a | e

 

      if statement : 

       if < condition > then < statement a> | if < condition > then < statement a> else < statement b>