nearly finished

10 files changed, 448 insertions, 30 deletions

diff --git a/src/minijava/symboltable/MClass.java b/src/minijava/symboltable/MClass.java
index 37bfcfb..10354a8 100644
--- a/src/minijava/symboltable/MClass.java
+++ b/src/minijava/symboltable/MClass.java
@@ -6,9 +6,11 @@ package minijava.symboltable;
 import minijava.typecheck.PrintError;
 
 public class MClass extends MLocalVarType {
-	public MClasses all_classes; // 所有类的列表
+	public MClasses all_classes; // 所有类的列表，在建立符号表时完成
 	public boolean isDeclared = false; // 是否已声明，用于检查符号表
-	public String extend_class_name = null; // 所继承的类
+	public String extend_class_name = null; // 所继承的类名
+	public MClass extend_class = null; // 所继承的类，在符号表建立完成后才能求得
+	public int extend_tag = 0; // 检测循环继承时用，0表示未检测
 	public MMethodList methods;
 
 	public MClass(String v_name, MClasses all, int m_line, int m_column) {
@@ -36,9 +38,50 @@ public class MClass extends MLocalVarType {
 			return "Method double declaration " + "\"" + method_name + "\".";
 		}
 		methods.addMethod(method);
+		method.method_class = this;
 		return null;
 	}
 	
+	// 检测类型名是否有效
+	public boolean validType(String s_type) {
+		if (s_type==MIdentifier.intType
+				|| 	s_type==MIdentifier.boolType 
+				||	s_type==MIdentifier.arrType 
+				||	s_type==MIdentifier.voidType
+				|| s_type==MIdentifier.sArrayType) {
+			return true;
+		}
+		
+		if (all_classes.findClassByName(s_type)!=null) {
+			return true;
+		}
+		
+		return false;
+	}
+	
+	// 对类进行类型检查
+	public boolean classVarCheck() {
+		boolean result = true;
+		for (int i=0; i<methods.size(); i++) {
+			result &= methods.methods.elementAt(i).validVars();
+		}
+		return result;
+	}
+	
+	public boolean classFuncCheck() {
+		boolean result = true;
+		for (int i=0; i<methods.size(); i++) {
+			result &= methods.methods.elementAt(i).validFunc();
+		}
+		return result;
+	}
+	
+	public void classStatementCheck() {
+		for (int i=0; i<methods.size(); i++) {
+			methods.methods.elementAt(i).checkStatements();
+		}
+	}
+	
 	// 调试输出: 打印该类的信息
 	public void printClass(int spaces) {
 		String ps = OutputFormat.spaces(spaces);
diff --git a/src/minijava/symboltable/MClasses.java b/src/minijava/symboltable/MClasses.java
index 2df2ba8..10bd009 100644
--- a/src/minijava/symboltable/MClasses.java
+++ b/src/minijava/symboltable/MClasses.java
@@ -5,9 +5,20 @@ package minijava.symboltable;
 
 import java.util.Vector;
 
+import minijava.typecheck.PrintError;
+
 public class MClasses extends MType {
 	public Vector<MClass> mj_classes = new Vector<MClass>(); // 用于存放类
 
+	MClass findClassByName(String c_name) {
+		for (int i=0; i<mj_classes.size(); i++) {
+			if (mj_classes.elementAt(i).getName().equals(c_name)) {
+				return mj_classes.elementAt(i);
+			}
+		}
+		return null;
+	}
+	
 	// 在表中插入类
 	public String InsertClass(MClass v_class) { 
 		String class_name = v_class.getName();
@@ -28,6 +39,59 @@ public class MClasses extends MType {
 		return false;
 	}
 	
+	public void buildClassRelation() {
+		// 通过extend_class_name确定extend_class, 并查找循环继承
+		for (int i=0; i<mj_classes.size(); i++) {
+			MClass m_class = mj_classes.elementAt(i);
+			String ext_name = m_class.extend_class_name;
+			if (ext_name!=null) {
+				m_class.extend_class = findClassByName(ext_name);
+			}
+		}
+		int tag = 1; // 扫描循环继承的标记
+		for (int i=0; i<mj_classes.size(); i++) {
+			MClass m_class = mj_classes.elementAt(i);
+			if (m_class.extend_tag==0) {
+				m_class.extend_tag = tag;
+				while (m_class.extend_class!=null) {
+					m_class = m_class.extend_class;
+					if (m_class.extend_tag==tag) { // 循环继承
+						PrintError.print(m_class.line, m_class.column, 
+								"Circular extend in class"+m_class.name);
+						break; // error
+					} else if (m_class.extend_tag==0) {
+						m_class.extend_tag = tag;
+					} else {
+						break; // no error
+					}
+				}
+				tag++;
+			}
+		}
+	}
+	
+	public boolean checkAllVars() {
+		boolean result = true;
+		for (int i=0; i<mj_classes.size(); i++) {
+			result &= mj_classes.elementAt(i).classVarCheck();
+		}
+		return result;
+	}
+	
+	public boolean checkAllFuncs() {
+		boolean result = true;
+		for (int i=0; i<mj_classes.size(); i++) {
+			result &= mj_classes.elementAt(i).classFuncCheck();
+		}
+		return result;
+	}
+	
+	public void checkAllStatements() {
+		for (int i=0; i<mj_classes.size(); i++) {
+			mj_classes.elementAt(i).classStatementCheck();
+		}
+	}
+	
 	// 调试输出: 打印所有的类的信息
 	public void printClasses(int spaces) {
 		for (int i=0; i<mj_classes.size(); i++) {
diff --git a/src/minijava/symboltable/MExpression.java b/src/minijava/symboltable/MExpression.java
index 17d6db8..4cf4724 100644
--- a/src/minijava/symboltable/MExpression.java
+++ b/src/minijava/symboltable/MExpression.java
@@ -1,5 +1,8 @@
 package minijava.symboltable;
 
+import minijava.syntaxtree.Identifier;
+import minijava.typecheck.PrintError;
+
 public class MExpression extends MType {
 	public enum Operator {
 		And, Smaller, Plus, Minus, Times, ArrayLookup,
@@ -15,12 +18,90 @@ public class MExpression extends MType {
 	// Expression value (for primary expression)
 	public String e_val;
 	
-	public MExpression(Operator op) {
+	public MExpression(int line, int column, Operator op) {
+		super(line, column);
 		e_op = op;
 		e_exp = new MPrimaryExpr();
 		e_list = new MExpressionList();
 	}
 	
+	public String exprType(MMethod m) {
+		switch (e_op) {
+		case And:
+			if (first.exprType(m)==MIdentifier.boolType
+			&& second.exprType(m)==MIdentifier.boolType) {
+				return MIdentifier.boolType;
+			} else {
+				PrintError.print(line, column, "Type mismatch");
+				return null;
+			}
+		case ArrayLen:
+			if (first.exprType(m)==MIdentifier.arrType) {
+				return MIdentifier.intType;
+			} else {
+				PrintError.print(line, column, "Type mismatch");
+				return null;
+			}
+		case ArrayLookup:
+			if (first.exprType(m)==MIdentifier.arrType
+			&& second.exprType(m)==MIdentifier.intType) {
+				return MIdentifier.intType;
+			} else {
+				PrintError.print(line, column, "Type mismatch");
+				return null;
+			}
+		case Smaller:
+			if (first.exprType(m)==MIdentifier.intType
+			&& second.exprType(m)==MIdentifier.intType) {
+				return MIdentifier.boolType;
+			} else {
+				PrintError.print(line, column, "Type mismatch");
+				return null;
+			}
+		case Plus:
+		case Minus:
+		case Times:
+			if (first.exprType(m)==MIdentifier.intType
+			&& second.exprType(m)==MIdentifier.intType) {
+				return MIdentifier.intType;
+			} else {
+				PrintError.print(line, column, "Type mismatch");
+				return null;
+			}
+		case MsgSend:
+			// expr.id(expr*)
+			String c_type = first.exprType(m);
+			MClass m_class = m.method_class.all_classes.findClassByName(c_type);
+			if (m_class==null) {
+				PrintError.print(line, column, "no class found in a message send expression");
+				return null;
+			}
+			int idx = m_class.methods.findMethod(e_id.name);
+			if (idx==-1) {
+				PrintError.print(line, column, "method " + e_id.name + " not found");
+				return null;
+			}
+			MMethod m_method = m_class.methods.methods.elementAt(idx);
+			if (e_list.size()!=m_method.paramList.size()) {
+				PrintError.print(line, column, "Method param size mismatch!");
+				return null;
+			}
+			for (int i=0; i<e_list.size(); i++) {
+				String t1 = e_list.e_list.elementAt(i).exprType(m);
+				String t2 = m_method.paramList.varlist.elementAt(i).typename;
+				if (!t1.equals(t2)) {
+					PrintError.print(line, column, "Method param type mismatch!");
+					return null;
+				}
+			}
+			return m_method.ret_type_name;
+		case Primary:
+			return e_exp.primExprType(m);
+		default:
+			return null;
+		}
+	}
+	
 	public void printExpr(int spaces) {
 		System.err.print(OutputFormat.spaces(spaces));
 		
@@ -54,6 +135,10 @@ public class MExpression extends MType {
 			second.printExpr(0);
 			break;
 		case ArrayLookup:
+			first.printExpr(0);
+			System.err.print("[");
+			second.printExpr(0);
+			System.err.print("]");
 		case ArrayLen:
 		case MsgSend:
 		}
diff --git a/src/minijava/symboltable/MIdentifier.java b/src/minijava/symboltable/MIdentifier.java
index 45340ac..5b3f88a 100644
--- a/src/minijava/symboltable/MIdentifier.java
+++ b/src/minijava/symboltable/MIdentifier.java
@@ -8,6 +8,8 @@ public class MIdentifier extends MType {
 	public static final String arrType = "int[]";
 	public static final String intType = "int";
 	public static final String boolType = "boolean";
+	public static final String voidType = "void";
+	public static final String sArrayType = "String[]";
 	
 	public MIdentifier(String v_name, int v_line, int v_column) {
 		super(v_line, v_column);
diff --git a/src/minijava/symboltable/MMethod.java b/src/minijava/symboltable/MMethod.java
index 7f57a40..2d2dc24 100644
--- a/src/minijava/symboltable/MMethod.java
+++ b/src/minijava/symboltable/MMethod.java
@@ -1,9 +1,11 @@
 package minijava.symboltable;
 
+import minijava.typecheck.PrintError;
+
 public class MMethod extends MLocalVarType {
 	MVarList params;
 	String ret_type_name;
-	MClass method_class;
+	public MClass method_class;
 	MVarList paramList;
 	public MStatementList statements;
 	public MExpression ret_expr;
@@ -37,6 +39,73 @@ public class MMethod extends MLocalVarType {
 		return null;
 	}
 	
+	// 检测函数的返回类型，参数类型，局部变量类型是否为有效类型
+	public boolean validVars() {
+		if (method_class.validType(ret_type_name)==false) {
+			PrintError.print(this.line, this.column, "Return type of method "+this.name+" invalid");
+			return false;
+		}
+		
+		for (int i=0; i<paramList.size(); i++) {
+			MVariable p_var = paramList.varlist.elementAt(i);
+			if (method_class.validType(p_var.typename)==false) {
+				PrintError.print(p_var.line, p_var.column, "Type "+p_var.typename+" invalid");
+				return false;
+			}
+		}
+		
+		for (int i=0; i<vars.size(); i++) {
+			MVariable m_var = vars.varlist.elementAt(i);
+			if (method_class.validType(m_var.typename)==false) {
+				PrintError.print(m_var.line, m_var.column, "Type "+m_var.typename+" invalid");
+				return false;
+			}
+		}
+		
+		return true;
+	}
+	
+	// 检查方法自身是否复合方法覆盖条件
+	public boolean validFunc() {
+		MClass m_class = method_class;
+		while (m_class.extend_class!=null) {
+			m_class = m_class.extend_class;
+			int idx = m_class.methods.findMethod(this.name);
+			if (idx!=-1) {
+				// 找到同名方法，检测是否能覆盖
+				if (this.ret_type_name.
+						equals(m_class.methods.methods.elementAt(idx))==false) {
+					PrintError.print(line, column, "Method " +
+						this.name + " has type different from the one in its parent class");
+					return false;
+				}
+			}
+		}
+		return true;
+	}
+	
+	// 从局部变量，参数表，类变量中查找变量
+	public MVariable findVarByName(String s) {
+		int idx;
+		idx = vars.findVar(s);
+		if (idx!=-1) {
+			return vars.varlist.elementAt(idx);
+		}
+		idx = paramList.findVar(s);
+		if (idx!=-1) {
+			return paramList.varlist.elementAt(idx);
+		}
+		idx = method_class.vars.findVar(s);
+		if (idx!=-1) {
+			return method_class.vars.varlist.elementAt(idx);
+		}
+		return null;
+	}
+	
+	public void checkStatements() {
+		statements.checkStatements(this);
+	}
+	
 	public void printMethod(int spaces) {
 		String ps = OutputFormat.spaces(spaces);
 		System.err.print(ps + this.ret_type_name + " " + this.name + "(");
diff --git a/src/minijava/symboltable/MPrimaryExpr.java b/src/minijava/symboltable/MPrimaryExpr.java
index ce4113c..ba233b5 100644
--- a/src/minijava/symboltable/MPrimaryExpr.java
+++ b/src/minijava/symboltable/MPrimaryExpr.java
@@ -1,5 +1,7 @@
 package minijava.symboltable;
 
+import minijava.typecheck.PrintError;
+
 public class MPrimaryExpr extends MType {
 	   /**
 	    * f0 -> IntegerLiteral()
@@ -35,6 +37,40 @@ public class MPrimaryExpr extends MType {
 		}
 	}
 	
+	public String primExprType(MMethod m) {
+		switch (e_type) {
+		case Int:
+			return MIdentifier.intType;
+		case Alloc:
+			return e_id.getName();
+		case ArrayAlloc:
+			return MIdentifier.arrType;
+		case Braket:
+			return e_exp.exprType(m);
+		case True:
+		case False:
+			return MIdentifier.boolType;
+		case Id:
+			MVariable m_var = m.findVarByName(e_id.name);
+			if (m_var!=null) {
+				return m_var.typename;
+			} else {
+				return null;
+			}
+		case Not:
+			if (e_exp.exprType(m)==MIdentifier.boolType) {
+				return MIdentifier.boolType;
+			} else {
+				PrintError.print(getLine(), getColumn(), "A non boolean expr after '!' operator");
+				return null;
+			}
+		case This:
+			return m.method_class.name;
+		default:
+			return null;
+		}
+	}
+	
 	public void printPrimExpr(int spaces) {
 		System.err.print(OutputFormat.spaces(spaces));
 		
@@ -49,6 +85,14 @@ public class MPrimaryExpr extends MType {
 		case Id:
 			System.err.print(e_id.getName());
 			break;
+		case Alloc:
+			System.err.print("new "+e_id.getName()+"()");
+			break;
+		case ArrayAlloc:
+			System.err.print("new int[");
+			e_exp.printExpr(0);
+			System.err.print("]");
+			break;
 		}
 	}
 }
diff --git a/src/minijava/symboltable/MStatement.java b/src/minijava/symboltable/MStatement.java
index 6410ca0..3610719 100644
--- a/src/minijava/symboltable/MStatement.java
+++ b/src/minijava/symboltable/MStatement.java
@@ -1,5 +1,7 @@
 package minijava.symboltable;
 
+import minijava.typecheck.PrintError;
+
 public class MStatement extends MType {
 	public enum Keyword {
 		Block, Assign, ArrAssign, If, While, Print;
@@ -10,7 +12,8 @@ public class MStatement extends MType {
 	public MExpression e_first, e_second; // for assign(e_first), array assign, if, while, print
 	public MStatement s_first, s_second; // for if, while
 	
-	public MStatement(Keyword keyw) {
+	public MStatement(int s_line, int s_column, Keyword keyw) {
+		super(s_line, s_column);
 		s_type = keyw;
 		s_list = null;
 		s_id = null;
@@ -18,6 +21,63 @@ public class MStatement extends MType {
 		s_first = s_second = null;
 	}
 	
+	public void checkStatement(MMethod m) {
+		switch (s_type) {
+		case ArrAssign:
+			// id[expr] = expr
+			if (m.findVarByName(s_id.name).typename==MIdentifier.arrType
+			&& e_first.exprType(m)==MIdentifier.intType 
+			&& e_second.exprType(m)==MIdentifier.intType) {
+				return;
+			} else {
+				PrintError.print(line, column, "type mismatch in array assign statement");
+			}
+			break;
+		case Assign:
+			// id = expr
+			MVariable m_var = m.findVarByName(s_id.name);
+			if (m_var==null) {
+				PrintError.print(line, column, "variable "+s_id.name+" not exist!");
+				return;
+			} else if (m_var.typename.equals(e_first.exprType(m))) {
+				return;
+			} else {
+				PrintError.print(line, column, "type mismatch in assign statement");
+			}
+			break;
+		case Block:
+			s_list.checkStatements(m);
+			break;
+		case If:
+			if (e_first.exprType(m)==MIdentifier.boolType) {
+				s_first.checkStatement(m);
+				s_second.checkStatement(m);
+			} else {
+				PrintError.print(line, column, "invalid type in if statement.");
+			}
+			break;
+		case Print:
+			if (e_first.exprType(m)!=null) {
+				return;
+			} else {
+				PrintError.print(line, column, "Invalid type in print statement");
+			}
+			break;
+		case While:
+			// while (expr) state
+			if (e_first.exprType(m)==MIdentifier.boolType) {
+				s_first.checkStatement(m);
+			} else {
+				PrintError.print(line, column, "invalid type in while statement.");
+			}
+			break;
+		default:
+			break;
+		
+		}
+		
+	}
+	
 	public void printStatement(int spaces) {
 		String sp = OutputFormat.spaces(spaces);
 		
@@ -31,17 +91,31 @@ public class MStatement extends MType {
 			System.err.println(")");
 			break;
 		case ArrAssign:
-			System.err.println(sp+"[]=");
+			System.err.println(sp+"[]= ("+s_id.getName()+") (");
+			e_first.printExpr(0);
+			System.err.print(") (");
+			e_second.printExpr(0);
+			System.err.println(")");
 			break;
 		case If:
-			System.err.println(sp+"if");
+			System.err.println(sp+"if (");
+			e_first.printExpr(0);
+			System.err.println(")");
+			s_first.printStatement(spaces+2);
+			s_second.printStatement(spaces+2);
 			break;
 		case While:
-			System.err.println(sp+"while");
+			System.err.println(sp+"while (");
+			e_first.printExpr(0);
+			System.err.println(")");
+			s_first.printStatement(spaces+2);
 			break;
 		case Print:
-			System.err.println(sp+"print");
+			System.err.println(sp+"print (");
+			e_first.printExpr(0);
+			System.err.println(")");
 			break;
 		}
 	}
+
 }
diff --git a/src/minijava/symboltable/MStatementList.java b/src/minijava/symboltable/MStatementList.java
index 034bc8b..3cb3b02 100644
--- a/src/minijava/symboltable/MStatementList.java
+++ b/src/minijava/symboltable/MStatementList.java
@@ -23,4 +23,11 @@ public class MStatementList extends MType {
 			s_list.elementAt(i).printStatement(spaces);
 		}
 	}
+
+	public void checkStatements(MMethod m) {
+		for (int i=0; i<s_list.size(); i++) {
+			s_list.elementAt(i).checkStatement(m);
+		}
+	}
+	
 }
diff --git a/src/minijava/typecheck/Main.java b/src/minijava/typecheck/Main.java
index 7319fe4..1c069ba 100644
--- a/src/minijava/typecheck/Main.java
+++ b/src/minijava/typecheck/Main.java
@@ -12,7 +12,7 @@ import minijava.syntaxtree.Node;
 import minijava.visitor.BuildSymbolTableVisitor;
 
 public class Main {
-
+	
 	public static void main(String[] args) {
 
 		try {
@@ -30,6 +30,17 @@ public class Main {
 				my_classes.printClasses(0);
 			}
 			
+			// 建立类的继承关系，寻找循环继承
+			my_classes.buildClassRelation();
+			
+			// 检查类型名有效性
+			my_classes.checkAllVars();
+			
+			// 检查方法错误覆盖
+			my_classes.checkAllFuncs();
+			
+			my_classes.checkAllStatements();
+			
 			// 打印错误信息
 			PrintError.printAll();
 		} catch (TokenMgrError e) {
diff --git a/src/minijava/visitor/BuildSymbolTableVisitor.java b/src/minijava/visitor/BuildSymbolTableVisitor.java
index 768c905..c99d0ab 100644
--- a/src/minijava/visitor/BuildSymbolTableVisitor.java
+++ b/src/minijava/visitor/BuildSymbolTableVisitor.java
@@ -110,9 +110,10 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     	  PrintError.print(m_class.getLine(), m_class.getColumn(), error_msg);
      
       // 往main class中添加main方法
-      MMethod main_method = new MMethod("main", "void", n.f6.beginLine, n.f6.beginColumn);
+      MMethod main_method = new MMethod("main", MIdentifier.voidType,
+    		  n.f6.beginLine, n.f6.beginColumn);
       MIdentifier argid = (MIdentifier) n.f11.accept(this, null);
-      MVariable param = new MVariable(argid.getName(), "String[]", 
+      MVariable param = new MVariable(argid.getName(), MIdentifier.sArrayType, 
     		  argid.getLine(), argid.getColumn());
       main_method.addParam(param);
       m_class.insertMethod(main_method);
@@ -247,7 +248,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
 	   MClass m_class = (MClass)argu;
 	   String ret_type = n.f1.accept(this, null).getName();
 	   String method_name = n.f2.accept(this, null).getName();
-	   MMethod m_method = new MMethod(method_name, ret_type, n.f2.f0.beginLine, n.f2.f0.beginColumn);
+	   MMethod m_method = new MMethod(method_name, ret_type, 
+			   n.f2.f0.beginLine, n.f2.f0.beginColumn);
 	   
 	   // 将定义的方法插入类中，如果出错则打印错误信息
 	   String _err = m_class.insertMethod(m_method);
@@ -364,7 +366,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> "}"
     */
    public MType visit(Block n, MType argu) {
-      MStatement s = new MStatement(MStatement.Keyword.Block);
+      MStatement s = new MStatement(n.f0.beginLine, n.f0.beginColumn,
+    		  MStatement.Keyword.Block);
       s.s_list = new MStatementList();
       if (argu!=null) { // should be a statement list
     	  ((MStatementList)argu).addStatement(s);
@@ -381,8 +384,10 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     */
    public MType visit(AssignmentStatement n, MType argu) {
       MStatementList m_list = (MStatementList) argu;
-      MStatement s = new MStatement(MStatement.Keyword.Assign);
-      s.s_id = (MIdentifier) n.f0.accept(this, null);
+      MIdentifier st_id = (MIdentifier) n.f0.accept(this, null);
+      MStatement s = new MStatement(st_id.getLine(), st_id.getColumn(),
+    		  MStatement.Keyword.Assign);
+      s.s_id = st_id;
       s.e_first = (MExpression) n.f2.accept(this, null);
       if (m_list!=null) { // a statement list
     	  m_list.addStatement(s);
@@ -401,8 +406,10 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     */
    public MType visit(ArrayAssignmentStatement n, MType argu) {
       MStatementList m_list = (MStatementList) argu;
-      MStatement s = new MStatement(MStatement.Keyword.ArrAssign);
-      s.s_id = (MIdentifier) n.f0.accept(this, null);
+      MIdentifier st_id = (MIdentifier) n.f0.accept(this, null);
+      MStatement s = new MStatement(st_id.getLine(), st_id.getColumn(),
+    		  MStatement.Keyword.ArrAssign);
+      s.s_id = st_id;
       s.e_first = (MExpression) n.f2.accept(this, null);
       s.e_second = (MExpression) n.f5.accept(this, null);
       if (m_list!=null) { // a statement list
@@ -422,7 +429,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     */
    public MType visit(IfStatement n, MType argu) {
       MStatementList m_list = (MStatementList) argu;
-      MStatement s = new MStatement(MStatement.Keyword.If);
+      MStatement s = new MStatement(n.f0.beginLine, n.f0.beginColumn,
+    		  MStatement.Keyword.If);
       s.e_first = (MExpression) n.f2.accept(this, null);
       s.s_first = (MStatement) n.f4.accept(this, null);
       s.s_second = (MStatement) n.f6.accept(this, null);
@@ -441,7 +449,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     */
    public MType visit(WhileStatement n, MType argu) {
 	   MStatementList m_list = (MStatementList)argu;
-	   MStatement s = new MStatement(MStatement.Keyword.While);
+	   MStatement s = new MStatement(n.f0.beginLine, n.f0.beginColumn,
+			   MStatement.Keyword.While);
 	   s.e_first = (MExpression) n.f2.accept(this, null);
 	   s.s_first = (MStatement) n.f4.accept(this, null);
 	   if (m_list!=null) {
@@ -459,7 +468,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     */
    public MType visit(PrintStatement n, MType argu) {
 	   MStatementList m_list = (MStatementList)argu;
-	   MStatement s = new MStatement(MStatement.Keyword.Print);
+	   MStatement s = new MStatement(n.f0.beginLine, n.f0.beginColumn,
+			   MStatement.Keyword.Print);
 	   s.e_first = (MExpression) n.f2.accept(this, null);
 	   if (m_list!=null) {
 		   m_list.addStatement(s);
@@ -488,7 +498,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> PrimaryExpression()
     */
    public MType visit(AndExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.And);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.And);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -503,7 +514,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> PrimaryExpression()
     */
    public MType visit(CompareExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.Smaller);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.Smaller);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -518,7 +530,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> PrimaryExpression()
     */
    public MType visit(PlusExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.Plus);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.Plus);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -533,7 +546,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> PrimaryExpression()
     */
    public MType visit(MinusExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.Minus);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.Minus);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -548,7 +562,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> PrimaryExpression()
     */
    public MType visit(TimesExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.Times);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.Times);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -564,7 +579,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f3 -> "]"
     */
    public MType visit(ArrayLookup n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.ArrayLookup);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.ArrayLookup);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.second = (MExpression) n.f2.accept(this, null);
 	   if (argu!=null) {
@@ -579,7 +595,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f2 -> "length"
     */
    public MType visit(ArrayLength n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.ArrayLen);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.ArrayLen);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   if (argu!=null) {
 		   ((MExpressionList)argu).add_expr(e);
@@ -596,7 +613,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     * f5 -> ")"
     */
    public MType visit(MessageSend n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.MsgSend);
+	   MExpression e = new MExpression(n.f1.beginLine, n.f1.beginColumn,
+			   MExpression.Operator.MsgSend);
 	   e.first = (MExpression) n.f0.accept(this, null);
 	   e.e_id = (MIdentifier) n.f2.accept(this, null);
 	   // 将表达式列表的内容添加至e.e_list
@@ -638,7 +656,8 @@ public class BuildSymbolTableVisitor extends GJDepthFirst<MType, MType> {
     *       | BracketExpression()
     */
    public MType visit(PrimaryExpression n, MType argu) {
-	   MExpression e = new MExpression(MExpression.Operator.Primary);
+	   // FIXME: cannot get line and column
+	   MExpression e = new MExpression(0, 0, MExpression.Operator.Primary);
 	   n.f0.accept(this, e.e_exp);
 	   if (argu!=null) { // a expression list
 		   ((MExpressionList)argu).add_expr(e);