实验三编译原理综合实验报告——(LR(0)语法分析的实现)

实验三 编译原理综合实验报告
--(LR(0)语法分析的实现)

一、实验名称:LR(0)语法分析的实现

二、仪器、设备:计算机

三、参考资料:《编译原理教程》习题解析与上机指导(西安电子科技大 胡元义等)

四、实验目的:
综合运用所学知识,集成词法分析、符号表管理等程序的成果,编程实现LR(0)算法,能根据预先定义的文法规则生成LR(0)分析表,并对输入串进行语法分析。
具体即要实现:录入合法的LR(0)文法,将输出LR(0)分析表,并可以对输入的句子进行语法分析输出相应语法树。
五、实验内容:(实验步骤)
⑴ 按实习目的和要求,用C或者C++语言编写一个LR(0)的语法分析程序,同时考虑相应的数据结构。
⑵ 调试
调试例子应包括符合文法规则的LR(0)文法,以及分析程序能够判别的若干错例。作为纠错部分的功能体现 。
⑶ 输出
对于所输入的LR(0)文法,不论对错,都应有明确的信息告诉外界。对于符合规则的LR(0)文法,将输出LR(0)分析表,并可以对输入的句子进行语法分析输出相应语法树。
⑷ 扩充
有余力的同学,可适当扩大分析算法。譬如:
① SLR(1)分析方法的实现
② LR(1)分析方法的实现

六、实验原理、数据(程序)记录
(一)实验原理:
利用LR(k)类分析算法的四个步骤,分别实现"移进"、"归约"、"成功"、"报错"的分析能力。同时采用相应的数据结构实现分析表的描述。
(二)程序框架:

#include "stdafx.h"
#include "GoData.h"
GoData::GoData()
{
iFrom = -1;
cChar = '\0';
iTo = -1;
}
GoData::~GoData()
{
}
// AnalyzeDlg.cpp : implementation file
//
#include "stdafx.h"
#include "LR0ForWin.h"
#include "AnalyzeDlg.h"
#include
#include
#include "Pair.h"
using namespace std;
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CAnalyzeDlg dialog

CAnalyzeDlg::CAnalyzeDlg(CWnd* pParent /*=NULL*/)
: CResizingDialog(CAnalyzeDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CAnalyzeDlg)
m_input = _T("");
//}}AFX_DATA_INIT
m_strTempFilename = "";
m_pTree = new CTreeDlg;
m_pTree->Create(IDD_DIALOG3, this);
m_pTree->SetControlInfo(IDC_TREE1, RESIZE_BOTH);
m_pTree->SetControlInfo(IDOK, ANCHORE_BOTTOM | ANCHORE_RIGHT);
}
CAnalyzeDlg::~CAnalyzeDlg()
{
m_pTree->DestroyWindow();
delete m_pTree;
}
void CAnalyzeDlg::DoDataExchange(CDataExchange* pDX)
{
CResizingDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CAnalyzeDlg)
DDX_Control(pDX, IDC_EDIT1, m_edit1);
DDX_Control(pDX, IDC_EXPLORER1, m_web);
DDX_Text(pDX, IDC_EDIT1, m_input);
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CAnalyzeDlg, CResizingDialog)
//{{AFX_MSG_MAP(CAnalyzeDlg

)
ON_BN_CLICKED(IDC_BUTTON1, OnButton1)
ON_BN_CLICKED(IDC_BUTTON2, OnButton2)
ON_WM_ACTIVATE()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CAnalyzeDlg message handlers
void CAnalyzeDlg::OnOK()
{
// TODO: Add extra validation here

//CDialog::OnOK();
}
void CAnalyzeDlg::OnCancel()
{
// TODO: Add extra cleanup here
if (m_strTempFilename != "")
DeleteFile(m_strTempFilename.c_str());
CResizingDialog::OnCancel();
}
void CAnalyzeDlg::OnButton1()
{
// TODO: Add your control notification handler code here
UpdateData(TRUE);
m_pTree->m_tree.DeleteAllItems();
for(int i = 0; i < m_input.GetLength(); i ++)
{
if (!m_g.IsInVt(m_input.GetAt(i)))
{
MessageBox("输入的句子不全部由终结符组成", "错误", MB_OK | MB_ICONSTOP);
return;
}
}
assert(TreeStack.empty());
m_input += "#";
char szTempPath[MAX_PATH];
char szTempName[MAX_PATH];
if (m_strTempFilename != "")
::DeleteFile(m_strTempFilename.c_str());
::GetTempPath(100,szTempPath);
::GetTempFileName(szTempPath,"LR0",0,szTempName);
m_strTempFilename = szTempName;
CStdioFile out;
out.Open(szTempName, CFile::modeCreate | CFile::modeWrite);
out.WriteString("\n");
out.WriteString("\n");
out.WriteString("Untitled Document\n");
out.WriteString("\n");
out.WriteString("\n");
out.WriteString("\n");
out.WriteString("

\n");
out.WriteString("\n\n\n\n\n\n\n \n");
vector Status;
vector Symbol;
int iStep = 1;
int iPos = 0;
Status.push_back(0);
Symbol.push_back('#');
Pair ToDo;
bool bErrorFlag = false;
bool bGoOn = true;
while ((bGoOn) && (!bErrorFlag))
{
assert(iPos < m_input.GetLength());
assert(Status.size() == Symbol.size());
ToDo = m_g.GetAction(Status.back(), m_input.GetAt(iPos));
int i, j;
switch (ToDo.one)
{
case 'S':
out.WriteString(GetStepInfo(iStep, Status, Symbol, m_input.Right(m_input.GetLength() - iPos), ToDo, -1));
Symbol.push_back(m_input.GetAt(iPos));
Status.push_back(ToDo.two);
iPos++;
break;
case 'R':
j = m_g.GetGoTo(Status[Status.size()-m_g.GetPrecept(ToDo.two).GetRight().length()-1], m_g.GetPrecept(ToDo.two).GetLeft()[0]);
assert(j != -1);
out.WriteString(GetStepInfo(iStep, Status, Symbol, m_input.Right(m_input.GetLength() - iPos), ToDo, j));
for(i = 0; i < m_g.GetPrecept(ToDo.two).GetRight().length(); i++)
{
Status.pop_back();
Symbol.pop_back();

}
Symbol.push_back(m_g.GetPrecept(ToDo.two).GetLeft()[0]);
Status.push_back(j);
TreeStack.push(ToDo.two);
break;
case 'a':
if (m_input.GetAt(iPos) == '#')
{
out.WriteString(GetStepInfo(iStep, Status, Symbol, m_input.Right(m_input.GetLength() - iPos), ToDo, -1));
bGoOn = false;
}
else
bErrorFlag = true;
break;
case 0:
bErrorFlag = true;
break;
default:
assert(false);
}
iStep++;
}
out.WriteString("

 步骤  状态栈 符号栈  输入串  ACTION  GOTO 
");
if (bErrorFlag)
{
out.WriteString("

分析失败,输入的字符串是不符合预定文法的!

\n");
//m_pTree->m_tree.DeleteAllItems();
while(!TreeStack.empty())
TreeStack.pop();
}
else
{
out.WriteString("

分析完成,输入的字符串是预定文法的句子

\n");
//HTREEITEM h = m_pTree->m_tree.GetRootItem();
//ExpandTree(h);
MakeTree();
}
out.WriteString("\n");
out.Close();
m_web.Navigate(szTempName,NULL,NULL,NULL,NULL);
m_edit1.SetFocus();
m_edit1.SetSel(0, -1);
}
BOOL CAnalyzeDlg::OnInitDialog()
{
CResizingDialog::OnInitDialog();

SetIcon(LoadIcon(::AfxGetInstanceHandle(), MAKEINTRESOURCE(IDR_MAINFRAME)),FALSE);
// TODO: Add extra initialization here
m_web.Navigate("about:blank",NULL,NULL,NULL,NULL);
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}
void CAnalyzeDlg::SetGrammar(const Grammar & g)
{
m_g = g;
}
CString CAnalyzeDlg::GetStepInfo(int iStep, const vector & Status, const vector & Symbol, CString sInput, Pair Action, int Goto)
{
CString rtn;
rtn.Format("  %d  \n",iStep);
CString t2 = "";
CString t;
int nCount = 0;
for (int i = 0; i < Status.size(); i++)
{
if (nCount % 2)
t.Format("%d", Status[i]);
else
t.Format("%d", Status[i]);
t2 += t;
nCount++;
}
rtn = rtn + "  " + t2 + "  \n  ";
t2 = "";
for(i = 0; i < Symbol.size(); i++)
{
t.Format("%c", Symbol[i]);
t2 += t;
}
rtn = rtn + t2 + "  \n";
rtn = rtn + "  " + sInput + "  \n";
if (Action.one != 'a')
t2.Format("%c%d", Action.one, Action.two);
else
t2 = "acc";
rtn = rtn + "  " + t2 + "  \n";
if (Goto == -1)
rtn += "      \n";
else
{
t2.Format("  %d   \n", Goto);
rtn += t2;
}
rtn += "\n";
return rtn;
}
void CAnalyzeDlg::MakeTree()
{
HTREEITEM hRoot = m_pTree->m_tree.InsertItem(CString(m_g.GetStart()));
CString temp;
HTREEITEM hItem = hRoot;
stack s;
s.push(hItem);
while (!TreeStack.empty())
{
temp = m_g.GetPrecept(Tre

eStack.top()).GetRight().c_str();
hItem = s.top();
s.pop();
TreeStack.pop();
for(int i = 0; i < temp.GetLength(); i++)
{
HTREEITEM hItem2;
hItem2 = m_pTree->m_tree.InsertItem(CString(temp.GetAt(i)), hItem);
if(m_g.IsInVn(temp.GetAt(i)))
{
s.push(hItem2);
}
}
m_pTree->m_tree.Expand(hItem, TVE_EXPAND);
}
assert(s.empty());
assert(TreeStack.empty());
}
void CAnalyzeDlg::OnButton2()
{
// TODO: Add your control notification handler code here
CRect rect;
GetWindowRect(rect);
//int iWidth = GetSystemMetrics(SM_CXSCREEN) - rect.right;
//if (iWidth < 200)
// iWidth = 200;
if(!m_pTree->IsWindowVisible())
m_pTree->SetWindowPos(&wndTopMost,GetSystemMetrics(SM_CXSCREEN) - 280, 0, 250, 350, SWP_SHOWWINDOW);
m_pTree->SetFocus();
}
void CAnalyzeDlg::OnActivate(UINT nState, CWnd* pWndOther, BOOL bMinimized)
{
CResizingDialog::OnActivate(nState, pWndOther, bMinimized);
if (nState == WA_INACTIVE)
m_pTree->SetWindowPos(&wndNoTopMost,0,0,0,0, SWP_NOMOVE | SWP_NOSIZE |SWP_NOACTIVATE );
else
m_pTree->SetWindowPos(&wndTopMost,0,0,0,0,SWP_NOSIZE | SWP_NOMOVE |SWP_NOACTIVATE );
}
七、实验结果分析
注意:本例是利用LR(0)分析来实现的语法分析,同学在写实验报告的时候,在结果分析这一块可以选用课堂讲过的LR(0)文法来说明验证结果即可。
同时附上你所选用的文法对应的LR(0)分析表。
八、实验体会(小结)。


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