private static void executeMain()
{
if (globalSymbolTable.Keys.Contains("main"))
{
if (globalSymbolTable["main"].type == "func")
{
int return_val = 0;
FuncValue main_func = ((FuncValue)globalSymbolTable["main"]);
ExecutorTools.executeFunction(main_func, new List <Value>(), main_func.line_num);
}
}
else
{
throw new ExecutorException("不存在main函数，无法执行！");
}
}
//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);
}
}
//返回程序执行的结果，可以是NullValue
public Value executeFunction()
{
return(ExecutorTools.executeFunction(this, new List <Value>(), line_num));
}
/*
* 初始化所有变量：规则（未给出初始化值initializer的，也就是只是声明的变量都赋0）
* declaratee→identifier | identifier[simple_expr] | identifier initializer | identifier [simple_expr] initializer | identifier[] initializer
* 接收参数declaratees：初始化数组/单个变量均可
* 可能出现错误：重复声明，void类型变量错误
* 声明单个变量：用数组给单个变量赋值，initializer值的类型与声明类型不符合
* 声明变量数组：用单个变量给数组变量赋值，initializer值的类型与声明类型不符合，initializer值的长度大于声明长度
* 可能有多个变量一起声明甚至初始化，但是他们类型必须相同（符合C语法）
*/
private static void initialize_declaratees(string type, List <NonterminalStackElement> declaratees, List <Dictionary <string, Value> > bindings_stack)
{
foreach (NonterminalStackElement declaratee in declaratees)
{
IdentifierStackElement id_node = (IdentifierStackElement)declaratee.branches[0];
string new_identifier = id_node.content;
int linenum = id_node.linenum;
//检查重复声明
Dictionary <string, Value> bindings = ExecutorTools.findBindings(bindings_stack, new_identifier, true);
//也就是已经有了同名变量
if (bindings != null)
{
throw new ExecutorException("重复声明已存在的变量" + new_identifier, id_node.linenum);
}
else
{
//那就在最上层准备声明
bindings = bindings_stack[bindings_stack.Count - 1];
//declaratee→identifier声明变量
if (declaratee.branches.Count == 1)
{
if (type == "int")
{
bindings.Add(new_identifier, new IntValue("int", false, "0", id_node.linenum));
}
else if (type == "real")
{
bindings.Add(new_identifier, new RealValue("real", false, "0.0", id_node.linenum));
}
else if (type == "char")
{
bindings.Add(new_identifier, new CharValue("char", false, "", id_node.linenum));
}
else if (type == "string")
{
bindings.Add(new_identifier, new StringValue("string", false, "", id_node.linenum));
}
else
{
throw new ExecutorException("试图声明一个void类型的变量" + new_identifier, id_node.linenum);
}
}
//declaratee→identifier initializer 声明并初始化变量
else if (declaratee.branches.Count == 2)
{
NonterminalStackElement initializer_node = (NonterminalStackElement)declaratee.branches[1];
if (initializer_node.branches.Count != 2)
{
throw new ExecutorException("试图用数组给单个变量" + new_identifier + "进行初始化", linenum);
}
//排除后，必然是initializer→=expr
NonterminalStackElement expr_node = (NonterminalStackElement)initializer_node.branches[1];
Value v = Evaluator.eval_expr(expr_node, mainFrameStack);
v = ExecutorTools.adjustType(type, v);
bindings.Add(new_identifier, v);
}
//declaratee→identifier[simple_expr] | identifier[] initializer声明定长数组，初始化auto自适应长度数组
else if (declaratee.branches.Count == 4)
{
StackElement third_child_of_last_declaratee = (StackElement)declaratee.branches[2];
//declaratee→identifier[] initializer
if (third_child_of_last_declaratee.type_code == 4)
{
//现在还不知道数组长度，要根据initializer算
int array_len;
NonterminalStackElement initializer_node = (NonterminalStackElement)declaratee.branches[3];
//initializer→ = expr |={ initializer_lst}
if (initializer_node.branches.Count != 4)
{
throw new ExecutorException("试图用单个变量给数组" + new_identifier + "进行初始化", linenum);
}
//排除后，必然是initializer→={initializer_lst}
NonterminalStackElement initializer_lst_node = (NonterminalStackElement)initializer_node.branches[2];
//获取initializer数组的长度 intializer_lst→expr | expr,initializer_lst | expr,
//获取给出的initializer中的值的集合
List <Value> given_values = new List <Value>();
while (initializer_lst_node.branches.Count == 3)
{
Value vv = Evaluator.eval_expr((NonterminalStackElement)initializer_lst_node.branches[0], mainFrameStack);
vv = ExecutorTools.adjustType(type, vv);
given_values.Add(vv);
initializer_lst_node = (NonterminalStackElement)initializer_lst_node.branches[2];
}
Value v = Evaluator.eval_expr((NonterminalStackElement)initializer_lst_node.branches[0], mainFrameStack);
v = ExecutorTools.adjustType(type, v);
given_values.Add(v);
initializer_lst_node = (NonterminalStackElement)initializer_lst_node.branches[2];
//根据给出的值数量，确定我们数组的长度
array_len = given_values.Count;
if (type == "int")
{
int[] arrayElements = new int[array_len];
for (int i = 0; i < array_len; i++)
{
if (given_values[i].type != "int")
{
throw new ExecutorException("用" + given_values[i].type + "类型给" + type + "类型数组变量" + new_identifier + "初始化", linenum);
}
IntValue value = (IntValue)given_values[i];
arrayElements[i] = value.value;
}
bindings.Add(new_identifier, new IntArrayValue("intArray", false, array_len, arrayElements, linenum));
}
else if (type == "real")
{
double[] arrayElements = new double[array_len];
for (int i = 0; i < array_len; i++)
{
if (given_values[i].type != "real")
{
throw new ExecutorException("用" + given_values[i].type + "类型给" + type + "类型数组变量" + new_identifier + "初始化", linenum);
}
RealValue value = (RealValue)given_values[i];
arrayElements[i] = value.value;
}
bindings.Add(new_identifier, new RealArrayValue("realArray", false, array_len, arrayElements, linenum));
}
else if (type == "char")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
if (given_values[i].type != "char")
{
throw new ExecutorException("用" + given_values[i].type + "类型给" + type + "类型数组变量" + new_identifier + "初始化", linenum);
}
CharValue value = (CharValue)given_values[i];
arrayElements[i] = value.value;
}
bindings.Add(new_identifier, new CharArrayValue("charArray", false, array_len, arrayElements, linenum));
}
else if (type == "string")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
if (given_values[i].type != "string")
{
throw new ExecutorException("用" + given_values[i].type + "类型给" + type + "类型数组变量" + new_identifier + "初始化", linenum);
}
StringValue value = (StringValue)given_values[i];
arrayElements[i] = value.value;
}
bindings.Add(new_identifier, new StringArrayValue("stringArray", false, array_len, arrayElements, linenum));
}
else
{
throw new ExecutorException("试图声明一个void类型的变量数组" + new_identifier, linenum);
}
}
//declaratee→identifier[simple_expr]
else
{
NonterminalStackElement simple_expr_node = (NonterminalStackElement)declaratee.branches[2];
int array_len = ExecutorTools.get_array_len_from_simple_expr(simple_expr_node, mainFrameStack);
if (type == "int")
{
int[] arrayElements = new int[array_len];
for (int i = 0; i < array_len; i++)
{
arrayElements[i] = 0;
}
bindings.Add(new_identifier, new IntArrayValue("intArray", false, array_len, arrayElements, linenum));
}
else if (type == "real")
{
double[] arrayElements = new double[array_len];
for (int i = 0; i < array_len; i++)
{
arrayElements[i] = 0.0;
}
bindings.Add(new_identifier, new RealArrayValue("realArray", false, array_len, arrayElements, linenum));
}
else if (type == "char")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
arrayElements[i] = "\0";
}
bindings.Add(new_identifier, new CharArrayValue("charArray", false, array_len, arrayElements, linenum));
}
else if (type == "string")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
arrayElements[i] = "";
}
bindings.Add(new_identifier, new StringArrayValue("stringArray", false, array_len, arrayElements, linenum));
}
else
{
throw new ExecutorException("试图声明一个void类型的变量数组" + new_identifier, linenum);
}
}
}
//declaratee→identifier [simple_expr] initializer
else if (declaratee.branches.Count == 5)
{
NonterminalStackElement simple_expr_node = (NonterminalStackElement)declaratee.branches[2];
//数组声明的长度
int array_len = ExecutorTools.get_array_len_from_simple_expr(simple_expr_node, mainFrameStack);
//现在还不知道被赋值的数组长度，要根据initializer算
NonterminalStackElement initializer_node = (NonterminalStackElement)declaratee.branches[4];
//initializer→ = expr | ={ initializer_lst}
if (initializer_node.branches.Count != 4)
{
throw new ExecutorException("试图用单个变量给数组" + new_identifier + "进行初始化", linenum);
}
//排除后，必然是initializer→={initializer_lst}
NonterminalStackElement initializer_lst_node = (NonterminalStackElement)initializer_node.branches[2];
//获取initializer数组的长度 intializer_lst→expr | expr,initializer_lst | expr,
//获取给出的initializer中的值的集合
List <Value> given_values = new List <Value>();
while (initializer_lst_node.branches.Count == 3)
{
Value vv = Evaluator.eval_expr((NonterminalStackElement)initializer_lst_node.branches[0], mainFrameStack);
vv = ExecutorTools.adjustType(type, vv);
given_values.Add(vv);
initializer_lst_node = (NonterminalStackElement)initializer_lst_node.branches[2];
}
Value v = Evaluator.eval_expr((NonterminalStackElement)initializer_lst_node.branches[0], mainFrameStack);
v = ExecutorTools.adjustType(type, v);
given_values.Add(v);
//赋值
if (given_values.Count > array_len)
{
throw new ExecutorException("数组" + new_identifier + "的初始值设定项长度" + given_values.Count + "大于声明的长度" + array_len, linenum);
}
if (type == "int")
{
int[] arrayElements = new int[array_len];
for (int i = 0; i < array_len; i++)
{
if (i < given_values.Count)
{
IntValue intv = (IntValue)given_values[i];
arrayElements[i] = intv.value;
}
else
{
arrayElements[i] = 0;
}
}
bindings.Add(new_identifier, new IntArrayValue("intArray", false, array_len, arrayElements, linenum));
}
else if (type == "real")
{
double[] arrayElements = new double[array_len];
for (int i = 0; i < array_len; i++)
{
if (i < given_values.Count)
{
RealValue intv = (RealValue)given_values[i];
arrayElements[i] = intv.value;
}
else
{
arrayElements[i] = 0.0;
}
}
bindings.Add(new_identifier, new RealArrayValue("realArray", false, array_len, arrayElements, linenum));
}
else if (type == "char")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
if (i < given_values.Count)
{
CharValue intv = (CharValue)given_values[i];
arrayElements[i] = intv.value;
}
else
{
arrayElements[i] = "\0";
}
}
bindings.Add(new_identifier, new CharArrayValue("charArray", false, array_len, arrayElements, linenum));
}
else if (type == "string")
{
string[] arrayElements = new string[array_len];
for (int i = 0; i < array_len; i++)
{
if (i < given_values.Count)
{
StringValue intv = (StringValue)given_values[i];
arrayElements[i] = intv.value;
}
else
{
arrayElements[i] = "";
}
}
bindings.Add(new_identifier, new StringArrayValue("stringArray", false, array_len, arrayElements, linenum));
}
else
{
throw new ExecutorException("试图声明一个void类型的变量数组" + new_identifier, linenum);
}
}
else
{
throw new ExecutorException("initialize_declaratee_withzero出现不正常的错误，可能是语法树解析declaratee出现问题");
}
}
}
}
