追溯到英語語法分析器

我最近問了一個關於編寫一個非常基本的英語語法分析器的問題。我認爲這可能有助於展示一些代碼（雖然非常難看），以指定我在實現語法時需要幫助的地方。這是代碼。評論表明問題。追溯到英語語法分析器

#include "std_lib_facilities.h" 

string sentence(); 
string noun(); 
string verb(); 

string article() 
{ 
string words = sentence(); // not sure how to check for words 
      if (words == "the") 
      words = sentence(); 
      else return words;   
} 

string verb() 
{ 
string words = sentence(); // not sure how to check for words 
      if (words == "rules" || words == "fly" || words == "swim") 
      words = sentence(); 
      else return words;     
} 

string noun() 
{ 
string words = sentence(); // not sure how to check for words 
      if (words == "birds" || words == "fish" || words == "C++") 
      words = sentence(); 
      else return words;     
} 

string conjunction() 
{ 
string words = sentence(); // not sure how to check for words 
      if (words == "and" || words == "but" || words == "or") 
      words = sentence(); 
      else return words;     
} 

string sentence() 
{ 
if (noun()){ // this fails to compile, not sure how to check this 
      // error message says could not convert noun to bool 
    if (verb()) 
     cout << "OK.\n"; 
    else cout << "Not OK.\n";} 
else if (article()){ 
        if (sentence()) // will this create a loop? 
         cout << "Ok.\n"; 
        else cout << "Not Ok.\n";} 
else if (conjunction()){ 
    if (sentence()) // actually needs to be sentence conjunction sentence 
     cout << "Ok.\n"; 
     else cout << "Not Ok.\n"; 
else cout << "Not OK.\n"; 

} 


int main() 
{         
string words; 
cout << "Enter sentence.\n"; 
while(cin >> words){ 
     sentence(); 
     } 
keep_window_open(); // this function is part of the facilities library 
}

該代碼是非常不完整的，但基本上是一個框架，爲什麼需要發生。主要的問題是我需要檢查一個函數是否爲真，並且我需要知道如何比較用戶輸入和被調用的函數（除了strcasecmp（）之外的任何東西）？它還沒有用在書中，所以必須是另一種方式）。我也擔心可能存在多個「OK」或「不好」的輸出，但我會在後面擔心。

來源

2009-06-23 Alex

編輯原始問題以包含此代碼可能會更好。 – CoderDennis 2009-06-23 20:49:38

我做了，沒有迴應。 – Alex 2009-06-23 21:59:12