/* term → factor more_factor
* factor→+factor |-factor|number|identifier more_identifier|(expr)|"string"|'char'
* more_factor→ε|mul_op factor more_factor
* mul_op → *|/
* 如法炮制
*/
public static Value eval_term(NonterminalStackElement term_node, List <Dictionary <string, Value> > bindings_stack)
{
NonterminalStackElement factor_node = (NonterminalStackElement)term_node.branches[0];
NonterminalStackElement more_factor_node;
more_factor_node = (NonterminalStackElement)term_node.branches[1];
Value first_factor_value = eval_factor(factor_node, bindings_stack);
//more_factor → ε
while (more_factor_node.branches.Count == 3)
{
NonterminalStackElement mul_op_node = (NonterminalStackElement)more_factor_node.branches[0];
OtherTerminalStackElement mul_op = (OtherTerminalStackElement)mul_op_node.branches[0];
NonterminalStackElement second_factor_node = (NonterminalStackElement)more_factor_node.branches[1];
Value second_factor_value = eval_factor(second_factor_node, bindings_stack);
if (Value.computable_types.Contains(first_factor_value.type) && Value.computable_types.Contains(second_factor_value.type))
{
first_factor_value = first_factor_value.mathCalculate(second_factor_value, mul_op.content);
}
else
{
throw new ExecutorException("无法直接进行乘除运算的类型", mul_op.linenum);
}
more_factor_node = (NonterminalStackElement)more_factor_node.branches[2];
}
return(first_factor_value);
}
//当该节点为declare_stmt时进入这个函数，把变量添加到符号表bindings
//可能一个declare语句会声明很多个变量，这些变量可能是数组也可能不是，这些变量可能被赋值也可能没有
// declare_stmt→type declaratee_lst;
public static void declareVaraible(NonterminalStackElement declarate_stmt, List <Dictionary <string, Value> > bindings_stack)
{
if (declarate_stmt.branches.Count == 3)
{
NonterminalStackElement type_nonterminal = (NonterminalStackElement)declarate_stmt.branches[0];
OtherTerminalStackElement type_node = (OtherTerminalStackElement)type_nonterminal.branches[0];
//获得变量类型
string type = type_node.content;
//声明的所有变量名
List <NonterminalStackElement> declaratees = new List <NonterminalStackElement>();
//有两种可能：declaratee_lst→declaratee,declaratee_lst|declaratee
NonterminalStackElement declaratee_lst_node = (NonterminalStackElement)declarate_stmt.branches[1];
//处理递归，把每个declaratee加到declaratees
while (declaratee_lst_node.branches.Count != 1)
{
NonterminalStackElement first_declaratee_node = (NonterminalStackElement)declaratee_lst_node.branches[0];
declaratees.Add(first_declaratee_node);
declaratee_lst_node = (NonterminalStackElement)declaratee_lst_node.branches[2];
}
NonterminalStackElement declaratee_node = (NonterminalStackElement)declaratee_lst_node.branches[0];
declaratees.Add(declaratee_node);
//现在已经获取到的东西有：变量类型（暂时未区分数组），声明的变量个数，所有的declaratees
//还缺少：初始化所有变量
initialize_declaratees(type, declaratees, bindings_stack);
}
else
{
throw new ExecutorException("语法树的declare_stmt应该有且只有三个子结点");
}
}
//logical_expr→relational_expr logical_expr_more
// logical_expr_more→ ε | logical_op relational_expr logical_expr_more
public static Value eval_logical_expr(NonterminalStackElement logical_expr_node, List <Dictionary <string, Value> > bindings_stack)
{
if (logical_expr_node.branches.Count != 2)
{
throw new ExecutorException("文法发生了变化", logical_expr_node.linenum);
}
else
{
NonterminalStackElement relational_expr_node = (NonterminalStackElement)logical_expr_node.branches[0];
NonterminalStackElement logical_expr_more_node = (NonterminalStackElement)logical_expr_node.branches[1];
Value first_relational_expr_value = eval_relational_expr(relational_expr_node, bindings_stack);
//逐个迭代，很自然的左结合
while (logical_expr_more_node.branches.Count == 3)
{
NonterminalStackElement logical_op_node = (NonterminalStackElement)logical_expr_more_node.branches[0];
NonterminalStackElement second_relational_expr_node = (NonterminalStackElement)logical_expr_more_node.branches[1];
OtherTerminalStackElement logical_op = (OtherTerminalStackElement)logical_op_node.branches[0];
if (logical_op.content == "&&")
{
//short circuit evaluation短路求值
if (!first_relational_expr_value.getBoolean())
{
return(new BoolValue("bool", true, false, logical_op.linenum));
}
//短路求值！
Value second_relational_expr_value = eval_relational_expr(second_relational_expr_node, bindings_stack);
first_relational_expr_value = new BoolValue("bool", true, second_relational_expr_value.getBoolean(), logical_op.linenum);
}
else
{
//short circuit evaluation短路求值
if (first_relational_expr_value.getBoolean())
{
return(new BoolValue("bool", true, true, logical_op.linenum));
}
//短路求值！
Value second_relational_expr_value = eval_relational_expr(second_relational_expr_node, bindings_stack);
first_relational_expr_value = new BoolValue("bool", true, second_relational_expr_value.getBoolean(), logical_op.linenum);
}
logical_expr_more_node = (NonterminalStackElement)logical_expr_more_node.branches[2];
}
return(first_relational_expr_value);
}
}
//relational_expr→simple_expr relational_expr_more 返回一个value，这个value是truthy还是falsey交给上层函数
// relational_expr_more →ε | comparasion_op simple_expr relational_expr_more
//这里只要进行了compare，那返回int value而不是其他的，其原因是：3>2>1 -> false
public static Value eval_relational_expr(NonterminalStackElement relational_expr_node, List <Dictionary <string, Value> > bindings_stack)
{
NonterminalStackElement simple_expr_node = (NonterminalStackElement)relational_expr_node.branches[0];
NonterminalStackElement relational_expr_more_node = (NonterminalStackElement)relational_expr_node.branches[1];
//这里面临一个问题，如果comparison是==或者空，那么simple_expr什么都可以，如果comparison是> <=等等，那就只能是number
Value first_simple_expr_value = eval_simple_expr(simple_expr_node, bindings_stack);
while (relational_expr_more_node.branches.Count == 3)
{
NonterminalStackElement comparison_op_node = (NonterminalStackElement)relational_expr_more_node.branches[0];
NonterminalStackElement second_simple_expr = (NonterminalStackElement)relational_expr_more_node.branches[1];
relational_expr_more_node = (NonterminalStackElement)relational_expr_more_node.branches[2];
OtherTerminalStackElement comparison_op = (OtherTerminalStackElement)comparison_op_node.branches[0];
if (comparison_op.content == "==")
{
first_simple_expr_value = first_simple_expr_value.compareWith(eval_simple_expr(second_simple_expr, bindings_stack));
}
//这里相对上面是反过来的（不等于）
else if (comparison_op.content == "!=" || comparison_op.content == "<>")
{
IntValue result = first_simple_expr_value.compareWith(eval_simple_expr(second_simple_expr, bindings_stack));
if (result.value == 0)
{
result.value = 1;
}
else
{
result.value = 0;
}
first_simple_expr_value = result;
}
else
{
first_simple_expr_value = first_simple_expr_value.compareWith(eval_simple_expr(second_simple_expr, bindings_stack), comparison_op.content);
}
}
return(first_simple_expr_value);
}
/* Function: 返回type类型的Value
* 若不能返回type类型的Value，那么就报错
* 注意：要区分负数，把负数放到value里面返回
* 引入type的原因：real i = 1 + 2; 在evaluate这个expr时，我们不知道到底是int还是real
* 相关的产生式：
* simple_expr→term more_term
* term→factor more_factor
* more_term→ε|add_op term more_term
* add_op→+|-
*/
public static Value eval_simple_expr(NonterminalStackElement simple_expr_node, List <Dictionary <string, Value> > bindings_stack)
{
NonterminalStackElement term_node = (NonterminalStackElement)simple_expr_node.branches[0];
NonterminalStackElement more_term_node = (NonterminalStackElement)simple_expr_node.branches[1];
Value first_term_value = eval_term(term_node, bindings_stack);
while (more_term_node.branches.Count == 3)
{
NonterminalStackElement add_op_node = (NonterminalStackElement)more_term_node.branches[0];
OtherTerminalStackElement add_op = (OtherTerminalStackElement)add_op_node.branches[0];
NonterminalStackElement second_term_node = (NonterminalStackElement)more_term_node.branches[1];
Value second_term_value = eval_term(second_term_node, bindings_stack);
if (Value.computable_types.Contains(first_term_value.type) && Value.computable_types.Contains(second_term_value.type))
{
first_term_value = first_term_value.mathCalculate(second_term_value, add_op.content);
}
else
{
throw new ExecutorException("无法直接进行加减运算的类型", add_op.linenum);
}
more_term_node = (NonterminalStackElement)more_term_node.branches[2];
}
return(first_term_value);
}
//这里情况就不同了，上面是对应着+-*/四则运算的，所以char/string/数组 都不应该直接进行这些运算，但是他们可以被访问赋值，因此这里不做过多限制
/*
* factor→+factor |-factor|number|identifier more_identifier|(expr)|"string"|'char'
* more_identifier→ ε | [simple_expr] | () | (param_values)
* number→real_number |integer
*/
public static Value eval_factor(NonterminalStackElement factor_node, List <Dictionary <string, Value> > bindings_stack)
{
StackElement first_child = (StackElement)factor_node.branches[0];
//factor → number | "string" | 'char'
if (factor_node.branches.Count == 1)
{
//char
if (first_child.type_code == 7)
{
CharStackElement char_node = (CharStackElement)first_child;
return(new CharValue("char", true, char_node.content, char_node.linenum));
}
//string
else if (first_child.type_code == 8)
{
StringStackElement string_node = (StringStackElement)first_child;
return(new StringValue("string", true, string_node.content, string_node.linenum));
}
//number
else if (first_child.type_code == 3)
{
NonterminalStackElement number_node = (NonterminalStackElement)first_child;
return(eval_number(number_node));
}
else
{
throw new ExecutorException("eval_factor运行中发现factor文法发生了意想不到的变化");
}
}
//factor→+factor |-factor | identifier more_identifier
else if (factor_node.branches.Count == 2)
{
//+ - factor
if (first_child.type_code == 4)
{
int linenum = ((OtherTerminalStackElement)first_child).linenum;
OtherTerminalStackElement positive_or_negative = (OtherTerminalStackElement)first_child;
NonterminalStackElement child_factor_node = (NonterminalStackElement)factor_node.branches[1];
if (positive_or_negative.content == "+")
{
return(eval_factor(child_factor_node, bindings_stack));
}
//负号就要把值的符号颠倒
else
{
Value child_factor_node_value = eval_factor(child_factor_node, bindings_stack);
if (!Value.computable_types.Contains(child_factor_node_value.type))
{
throw new ExecutorException("不可在非数值类型前加上正号或者负号", linenum);
}
if (child_factor_node_value.type == "real")
{
RealValue value = (RealValue)child_factor_node_value;
value.value = -value.value;
return(value);
}
else if (child_factor_node_value.type == "int")
{
IntValue value = (IntValue)child_factor_node_value;
value.value = -value.value;
return(value);
}
else if (child_factor_node_value.type == "number")
{
NumberValue value = (NumberValue)child_factor_node_value;
value.value = -value.value;
return(value);
}
else
{
throw new ExecutorException("eval_factor运行中发现factor文法发生了意想不到的变化");
}
}
}
//factor→ identifier more_identifier
// more_identifier→ε | [simple_expr] | () | (param_values)
else
{
IdentifierStackElement identifier_node = (IdentifierStackElement)factor_node.branches[0];
int linenum = identifier_node.linenum;
NonterminalStackElement more_identifier_node = (NonterminalStackElement)factor_node.branches[1];
//检查是否定义
Dictionary <string, Value> bindings = ExecutorTools.findBindings(bindings_stack, identifier_node.content);
if (bindings != null)
{
//只是访问一个identifier 即 factor→ identifier
// more_identifier→ε
if (more_identifier_node.branches.Count == 0)
{
Value identifier_value = bindings[identifier_node.content];
return(identifier_value);
}
//应该是调用了一个不接受任何参数的函数比如foo()这样， more_identifier→ ()
else if (more_identifier_node.branches.Count == 2)
{
Value identifier_value = bindings[identifier_node.content];
if (identifier_value.type != "func")
{
throw new ExecutorException("标识符后带()应该是调用函数，但该标识符" + identifier_node.content + "对应函数并不存在", linenum);
}
FuncValue relevant_fucntion = (FuncValue)identifier_value;
Value return_value = relevant_fucntion.executeFunction();
return(return_value);
}
// 应该是调用了一个带参数的函数，或者是访问数组的某个元素 more_identifier → [simple_expr] | (param_values)
else if (more_identifier_node.branches.Count == 3)
{
Value identifier_value = bindings[identifier_node.content];
NonterminalStackElement second_element = (NonterminalStackElement)more_identifier_node.branches[1];
// more_identifier → [simple_expr] 要检查：第一，数组访问越界了没有；第二，访问的数组元素类型是否与要求的类型type相符合
if (second_element.name == "simple_expr")
{
//类型错误
if (!identifier_value.type.Contains("Array"))
{
throw new ExecutorException("标识符后带[ ]应该是访问数组某个元素，但该标识符" + identifier_node.content + "对应的并不是数组", linenum);
}
string array_type = identifier_value.type.Substring(0, identifier_value.type.Length - 5);
NonterminalStackElement simple_expr_node = second_element;
int index_to_access = ExecutorTools.get_array_len_from_simple_expr(simple_expr_node, bindings_stack);
//越界错误
if (index_to_access >= identifier_value.getArrayLen())
{
throw new ExecutorException("访问数组" + identifier_node.content + "时出现越界访问错误，数组长度只有" + identifier_value.getArrayLen(), linenum);
}
//eval要求就是获取到值，所以这里直接获取数组中元素的值，再转换为Value类型
else
{
if (identifier_value.type.Contains("int"))
{
return(new IntValue("int", false, identifier_value.getIntArrayElement(index_to_access).ToString(), linenum));
}
else if (identifier_value.type.Contains("real"))
{
return(new RealValue("real", false, identifier_value.getRealArrayElement(index_to_access).ToString(), linenum));
}
else if (identifier_value.type.Contains("int"))
{
return(new CharValue("char", false, identifier_value.getCharArrayElement(index_to_access).ToString(), linenum));
}
else
{
return(new StringValue("string", false, identifier_value.getStringArrayElement(index_to_access).ToString(), linenum));
}
}
}
// more_identifier → (param_values) 要检查：第一，函数签名是否符合（类型，次序）；第二，函数返回类型是否与要求的类型type相符合
else if (second_element.name == "param_values")
{
//类型错误
if (!identifier_value.type.Contains("func"))
{
throw new ExecutorException(identifier_node.content + "对应的并不是函数，无法调用", linenum);
}
FuncValue func_value = (FuncValue)identifier_value;
List <Value> args = new List <Value>();
NonterminalStackElement expr_node;
//param_values →expr,param_values|expr
NonterminalStackElement param_values_node = second_element;
while (param_values_node.branches.Count == 3)
{
expr_node = (NonterminalStackElement)param_values_node.branches[0];
param_values_node = (NonterminalStackElement)param_values_node.branches[2];
args.Add(eval_expr(expr_node, bindings_stack));
}
expr_node = (NonterminalStackElement)param_values_node.branches[0];
args.Add(eval_expr(expr_node, bindings_stack));
return(ExecutorTools.executeFunction(func_value, args, linenum));
}
else
{
throw new ExecutorException("文法发生了变化", linenum);
}
}
else
{
//Value relevant_value = Frame.curr_frame.local_bindings[identifier_node.content];
throw new ExecutorException("怎么到这的？", linenum);
}
}
throw new ExecutorException("语句中访问未定义的标识符" + identifier_node.content, linenum);
}
}
//factor→ ( expr )
else if (factor_node.branches.Count == 3)
{
NonterminalStackElement expr_node = (NonterminalStackElement)factor_node.branches[1];
return(eval_expr(expr_node, bindings_stack));
}
else
{
throw new ExecutorException("文法发生了变化", factor_node.linenum);
}
}
public override string ToString()
{
string text = "";
if (type_code == 1)
{
IdentifierStackElement e = (IdentifierStackElement)this;
text += "第" + e.linenum + "行标识符";
text += e.content;
}
else if (type_code == 2)
{
IntStackElement e = (IntStackElement)this;
text += "第" + e.linenum + "行整数";
text += e.content;
}
else if (type_code == 3)
{
NonterminalStackElement e = (NonterminalStackElement)this;
text += "非终结符";
text += e.name;
//递归调用
foreach (StackElement s in e.branches)
{
text += Environment.NewLine;
for (int i = 1; i < s.layers; i++)
{
text += " ";
}
text += s.ToString();
}
}
else if (type_code == 4)
{
OtherTerminalStackElement e = (OtherTerminalStackElement)this;
text += "第" + e.linenum + "行终结符";
text += e.content;
}
else if (type_code == 5)
{
RealStackElement e = (RealStackElement)this;
text += "第" + e.linenum + "行实数";
text += e.content;
}
else if (type_code == 7)
{
CharStackElement e = (CharStackElement)this;
text += "第" + e.linenum + "行字符";
text += e.content;
}
else if (type_code == 8)
{
StringStackElement e = (StringStackElement)this;
text += "第" + e.linenum + "行字符串";
text += e.content;
}
else
{
StateStackElement e = (StateStackElement)this;
text += "状态" + e.state;
}
return(text);
}
//执行函数（传入参数，返回类型等等）
//注意创建一个新的bindings和Stack，且这个Stack目前只有globalBingdings->newBindings
//可能return null-->（仅在void函数中可能）
public static Value executeFunction(FuncValue func_value, List <Value> arguments_lst, int linenum)
{
//可以看到，所有的东西都是局部变量，因此函数调用结束这些Bindings都会自动free
List <Dictionary <string, Value> > binding_stack = new List <Dictionary <string, Value> >();
Dictionary <string, Value> local_bindings = new Dictionary <string, Value>();
binding_stack.Add(Executor.globalSymbolTable);
binding_stack.Add(local_bindings);
//获得返回类型
NonterminalStackElement return_type_node = (NonterminalStackElement)func_value.func_def_node.branches[0];
OtherTerminalStackElement specific_return_type_node = (OtherTerminalStackElement)return_type_node.branches[0];
string return_type = specific_return_type_node.content;
//获得函数名
NonterminalStackElement func_declaratee = (NonterminalStackElement)func_value.func_def_node.branches[1];
IdentifierStackElement identifier_node = (IdentifierStackElement)func_declaratee.branches[0];
string func_name = identifier_node.content;
List <string> params_lst = new List <string>();
//part1 传参
//先把实参传进来（加到local_bindings顺便做一个类型检查，函数签名和传入参数）
//func_declaratee →identifier()|identifier(param_lst)
if (func_declaratee.branches.Count == 4)
{
int index = 0;
NonterminalStackElement param_lst_node = (NonterminalStackElement)func_declaratee.branches[2];
//param_lst→param_declaration,param_lst | param_declaration
NonterminalStackElement param_declaration_node = (NonterminalStackElement)param_lst_node.branches[0];
while (param_lst_node.branches.Count == 3)
{
if (arguments_lst.Count <= index)
{
throw new ExecutorException("传入实参多于形参", linenum);
}
//param_declaration→type identifier|type identifier[simple_expr]
NonterminalStackElement type_node = (NonterminalStackElement)param_declaration_node.branches[0];
OtherTerminalStackElement specific_type_node = (OtherTerminalStackElement)type_node.branches[0];
IdentifierStackElement identifier_Node = (IdentifierStackElement)param_declaration_node.branches[1];
param_lst_node = (NonterminalStackElement)param_lst_node.branches[2];
param_declaration_node = (NonterminalStackElement)param_lst_node.branches[0];
string type = specific_type_node.content;
//传入数组会更特殊
if (param_declaration_node.branches.Count == 4)
{
type += "Array";
if (arguments_lst[index].type != type)
{
throw new ExecutorException("函数形参类型与实际传入参数类型不符", linenum);
}
NonterminalStackElement simple_expr_node = (NonterminalStackElement)param_declaration_node.branches[3];
if (arguments_lst[index].getArrayLen() > get_array_len_from_simple_expr(simple_expr_node, binding_stack))
{
throw new ExecutorException("传入的数组长度大于对应的形参数组长度", linenum);
}
}
//如果符合要求，那就在local_bindings增加定义
if (arguments_lst[index].type == type)
{
local_bindings.Add(identifier_Node.content, arguments_lst[index]);
index++;
}
else
{
throw new ExecutorException("函数形参类型与实际传入参数类型不符", linenum);
}
}
if ((index + 1) > arguments_lst.Count)
{
throw new ExecutorException("传入实参少于形参", linenum);
}
//最后一个参数，重复一遍上面的工作
NonterminalStackElement _type_node = (NonterminalStackElement)param_declaration_node.branches[0];
OtherTerminalStackElement _specific_type_node = (OtherTerminalStackElement)_type_node.branches[0];
IdentifierStackElement _identifier_Node = (IdentifierStackElement)param_declaration_node.branches[1];
string _type = _specific_type_node.content;
//传入数组会更特殊
if (param_declaration_node.branches.Count == 4)
{
_type += "Array";
if (arguments_lst[index].type != _type)
{
throw new ExecutorException("函数形参类型与实际传入参数类型不符", linenum);
}
NonterminalStackElement simple_expr_node = (NonterminalStackElement)param_declaration_node.branches[3];
if (arguments_lst[index].getArrayLen() > get_array_len_from_simple_expr(simple_expr_node, binding_stack))
{
throw new ExecutorException("传入的数组长度大于对应的形参数组长度", linenum);
}
}
//如果符合要求，那就在local_bindings增加定义
if (arguments_lst[index].type == _type)
{
local_bindings.Add(_identifier_Node.content, arguments_lst[index]);
index++;
}
else
{
throw new ExecutorException("函数形参类型与实际传入参数类型不符", linenum);
}
}
//func_declaratee →identifier() 这样的话local_bindings就不需要任何东西了
else
{
if (arguments_lst.Count != 0)
{
throw new ExecutorException("函数" + identifier_node.content + "不需要接受任何参数", linenum);
}
//do nothing
}
//part2 实际执行
//func_definition→type func_declaratee {stmt_lst} | type func_declaratee {}
if (func_value.func_def_node.branches.Count == 4)
{
if (return_type == "void")
{
return(null);
}
else
{
throw new ExecutorException("函数" + identifier_node.content + "没有返回任何值", linenum);
}
}
//func_definition → type func_declaratee {stmt_lst}
//stmt_lst → stmt stmt_lst | stmt
NonterminalStackElement stmt_lst_node = (NonterminalStackElement)func_value.func_def_node.branches[3];
Value return_value = executeStmtLst(stmt_lst_node, binding_stack);
//如果返回一个NullValue或者Null，那要检查是否是void
if (return_value == null || return_value.type == "null")
{
if (return_type == "void")
{
return(null);
}
else
{
throw new ExecutorException("函数" + func_name + "的返回值必须是" + return_type + "类型", linenum);
}
}
//返回不是Null，返回了一个实际的Value，那就要检查类型是否相符，检查返回类型不是void
else
{
if (return_type == "void")
{
throw new ExecutorException("函数" + func_name + "的返回值必须是null", linenum);
}
else
{
try
{
Value v = adjustType(return_type, return_value);
return(v);
}
//重新捕获调整再抛出
catch (ExecutorException ee)
{
throw new ExecutorException("函数" + func_name + "的返回值必须是" + return_type + "类型", linenum);
}
catch (Exception eee)
{
throw eee;
}
}
}
}
private void recursiveAddNodes(StackElement e, TreeViewItem newItem)
{
try
{
if (e.type_code == 6)
{
throw new ParserException("这个表示状态的栈元素不应该出现在Tree的递归子结点中！");
}
else if (e.type_code == 1)
{
IdentifierStackElement ele = (IdentifierStackElement)e;
newItem.Header = "第" + ele.linenum + "行的标识符：" + ele.content;
}
else if (e.type_code == 2)
{
IntStackElement ele = (IntStackElement)e;
newItem.Header = "第" + ele.linenum + "行的整数：" + ele.content;
}
else if (e.type_code == 3)
{
NonterminalStackElement ele = (NonterminalStackElement)e;
newItem.Header = "非终结符：" + ele.name;
}
else if (e.type_code == 4)
{
OtherTerminalStackElement ele = (OtherTerminalStackElement)e;
newItem.Header = "第" + ele.linenum + "行的终结符：" + ele.content;
}
else if (e.type_code == 5)
{
RealStackElement ele = (RealStackElement)e;
newItem.Header = "第" + ele.linenum + "行的实数：" + ele.content;
}
else if (e.type_code == 7)
{
CharStackElement ele = (CharStackElement)e;
newItem.Header = "第" + ele.linenum + "行的字符：" + ele.content;
}
else if (e.type_code == 8)
{
StringStackElement ele = (StringStackElement)e;
newItem.Header = "第" + ele.linenum + "行的字符串：" + ele.content;
}
else
{
throw new ParserException("这是啥栈元素？");
}
//若是终结符，branches就是空，若不是非终结符，它也终究会走到末端叶子节点，也就是非终结符，然后递归终止
if (e.branches.Count != 0)
{
foreach (StackElement ele in e.branches)
{
TreeViewItem new_node = new TreeViewItem();
newItem.Items.Add(new_node);
recursiveAddNodes(ele, new_node);
}
}
}
catch (ParserException pe)
{
MessageBox.Show(pe.err_msg);
}
catch (Exception ee)
{
MessageBox.Show(ee.ToString());
}
}
