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使用内联汇编动态调用DLL

lwch — Sun, 06 Feb 2011 14:21:00 GMT

1.首先我们必须知道C语言的调用约定�ؓ__cdecl(卛_��C��叛_��左依�ơ进�?��p��用者还原堆�?.
2.一条push指��o最多压�?个字�?当不��?个字节时应补�?个字�?��过4个字节时应该�׃��位到高位依次压栈.
3.pop指��o也和push一样一�ơ只能弹�?个字�?
4.我们需要一个CallStruct�c�d��来储存一个参�?

1 class CallStruct
2     {
3     public:
4         INT            Integer;
5         BOOL        Bool;
6         DOUBLE        Real;
7         WCHAR        String[MAX_STRING];
8
9         enum TYPE
10         {
11             ctInteger,
12             ctString,
13             ctBool,
14             ctReal,
15             ctVoid,
16         }Type;
17
18         CallStruct() : Integer(0),Bool(FALSE),Real(0)
19         {
20             String[0]    = 0;
21         }
22
23         CallStruct(const NAutoPtr<VirtualMachine::VarClass>& Var) : Integer(Var->Integer),Bool(Var->Bool),Real(Var->Real),Type((TYPE)Var->Type)
24         {
25             if(Type == ctString) wcscpy(String,Var->String);
26         }
27     };

5.我们需要一个列表来存放参数和一个返回值对象来存放�q�回�?

1 List<NAutoPtr<CallStruct>> VarList;
2 NAutoPtr<CallStruct> Return;

6.最后我们需要一个HMODULE和一个FARPROC分别存放dll的句柄和函数地址.

1 HMODULE hModule;
2 FARPROC FunctionPtr;

7.然后我们��d��几个功能函数.

1     BOOL AddVar(NAutoPtr<VirtualMachine::VarClass>& Var);
2     BOOL SetReturnType(CallStruct::TYPE Type);
3     BOOL SetLibName(LPTSTR Name);
4     BOOL SetFunctionName(LPTSTR Name);

注意:GetProcAddress�W�二个参数只接受LPCSTR�c�d��的字�W�串,应此如果传入的是Unicode�~�码的字�W�必��d��其�{换成ANSI�?
8.我们��d��一个函数Run用于调用函数.

1 BOOL CallMacro::Run()
2 {
3     if(FunctionPtr == 0 || Return.Buffer() == 0) return FALSE;
4     union RealStruct
5     {
6         double Real;
7         struct
8         {
9             int Head,Tail;
10         };
11     };
12     NAutoPtr<CallStruct> cs;
13     int Integer;
14     BOOL Bool;
15     RealStruct Real; // Push指��o一�ơ只能压�?字节
16     LPTSTR String;
17
18     int iEsp;
19     __asm mov int ptr[iEsp],esp; // 保存esp
20     for(int i=0;i<VarList.Size();i++)
21     {
22         cs = VarList[i];
23         Integer = cs->Integer;
24         Bool = cs->Bool;
25         Real.Real = cs->Real;
26         String = cs->String;
27         switch(cs->Type)
28         {
29         case CallStruct::ctInteger:
30             __asm push Integer;
31             break;
32         case CallStruct::ctString:
33             __asm push String;
34             break;
35         case CallStruct::ctBool:
36             __asm push Bool;
37             break;
38         case CallStruct::ctReal:
39             __asm push Real.Tail;
40             __asm push Real.Head;
41             break;
42         }
43     }
44     FARPROC proc = FunctionPtr;
45     int Head,Tail;
46     __asm
47     {
48         call proc
49         mov int ptr[Head],edx
50         mov int ptr[Tail],eax
51     }
52     switch(Return->Type)
53     {
54     case CallStruct::ctInteger:
55         Return->Integer = Tail;
56         break;
57     case CallStruct::ctString:
58         wcscpy(Return->String,(LPCTSTR)Tail);
59         break;
60     case CallStruct::ctBool:
61         Return->Bool = Tail;
62         break;
63     case CallStruct::ctReal:
64         __asm fstp [Real.Real];
65         Return->Real = Real.Real;
66         break;
67     }
68     // __declspec调用�U�定,需要手工还原堆�?/span>
69     __asm mov esp,int ptr[iEsp];
70     return TRUE;
71 }

Run函数首先��查是否已�l�装载了DLL�q�获得了函数地址,以及�q�回值类型是否已�l�定�?
然后�Ҏ(gu��)��c�d��依次��函数压�?
然后调用call指��o�q�保存返回�?(�q�里需要注意的�?span style="COLOR: red">当返回值类型�ؓdouble或float�c�d��时必��M��用fstp指��o从FPU寄存器栈的栈��的值取出来)
最后还原堆�?

然后我们来测试一�?
创徏一个名为TestDLL的DLL工程�q�添加函数Test.

1 TESTDLL_API double Test(double d,double* d1,WCHAR* lpBuffer)
2 {
3     if(d == 123.456789) MessageBox(0,lpBuffer,L"",0);
4     *d1 = 789.654;
5     return 77777;
6 }

然后创徏一个测试工�E?��d��相关文�g.
在_tmain中添加以下代�?

1 int _tmain(int argc, _TCHAR* argv[])
2 {
3     double d;
4     CallMacro cm;
5     NAutoPtr<VirtualMachine::VarClass> Var;
6
7     Var = new VirtualMachine::VarClass;
8     Var->Type = VirtualMachine::VarClass::vtString;
9     wcscpy(Var->String,L"aaaaa");
10     cm.AddVar(Var);
11
12     Var = new VirtualMachine::VarClass;
13     Var->Type = VirtualMachine::VarClass::vtInteger;
14     Var->Integer = (INT)&d;
15     cm.AddVar(Var);
16
17     Var = new VirtualMachine::VarClass;
18     Var->Type = VirtualMachine::VarClass::vtReal;
19     Var->Real = 123.456789;
20     cm.AddVar(Var);
21
22     cm.SetLibName(L"TestDll.dll");
23     cm.SetFunctionName(L"Test");
24     cm.SetReturnType(CallMacro::CallStruct::ctReal);
25     cm.Run();
26
27     wprintf(L"%f %f\n",d,cm.Return->Real);
28     system("pause");
29     return 0;
30 }

�~�译�q�运�?可以看到Test函数调用成功,�q�成功输出d的值和�q�回�?

最后给�?a href="http://www.shnenglu.com/Files/lwch/DLLTest.rar">完整代码.

lwch 2011-02-06 22:21 发表评论

lwch — Wed, 26 Jan 2011 14:11:00 GMT

�l?a href="http://www.shnenglu.com/lwch/archive/2011/01/22/139121.html" target=_blank>《面向组合子的一些测试�?/a> �q�一步完善代�?制作��法分析器.

我们首先需要一个Fail基类,他有一个纯虚函数Parser.

1 class Fail
2 {
3 public:
4 virtual NWString Parser(NWString& input)=0;
5 };

Parser的输入�ؓ要分析的字符�?输出为分析完成后剩余的字�W�串.

然后我们需要一个Ch和一个Str分别用来分析单个字符和一个字�W�串.

1 class Ch : public Fail
2 {
3 public:
4     Ch(WCHAR _value) : value(_value){}
5
6     NWString Parser(NWString& input);
7
8     WCHAR Value();
9 protected:
10     WCHAR value; // 待匹配串
11 };
12
13 class Str : public Fail
14 {
15 public:
16     Str(NWString _value) : value(_value){}
17
18     NWString Parser(NWString& input);
19 protected:
20     NWString value; // 待匹配串
21 };

然后是Seq,Alt和Any,分别表示�l�合,选择和��@�?

1 class Seq : public Fail
2 {
3 public:
4     Seq(const NAutoPtr<Fail>& _left,const NAutoPtr<Fail>& _right) : left(_left),right(_right){}
5
6     NWString Parser(NWString& input);
7 protected:
8     NAutoPtr<Fail> left;
9     NAutoPtr<Fail> right;
10 };
11
12 class Alt : public Fail
13 {
14 public:
15     Alt(const NAutoPtr<Fail>& _left,const NAutoPtr<Fail>& _right) : left(_left),right(_right){}
16
17     NWString Parser(NWString& input);
18 protected:
19     NAutoPtr<Fail> left;
20     NAutoPtr<Fail> right;
21 };
22
23 class Any : public Fail
24 {
25 public:
26     Any(const NAutoPtr<Fail>& _left,const int _count) : left(_left),count(_count){}
27
28     NWString Parser(NWString& input);
29 protected:
30     NAutoPtr<Fail> left;
31     int count;
32 };

最后我们需要一个Node�c�d��来存放以上这几类对象.

1 class Node
2 {
3 public:
4     Node(){}
5     Node(const NAutoPtr<Fail>& _left) : left(_left){}
6
7     friend NAutoPtr<Node> operator+(const NAutoPtr<Node>& left,const NAutoPtr<Node>& right);
8     friend NAutoPtr<Node> operator|(const NAutoPtr<Node>& left,const NAutoPtr<Node>& right);
9     friend NAutoPtr<Node> operator-(const NAutoPtr<Node>& left,const NAutoPtr<Node>& right);
10
11     static NAutoPtr<Node> OnceMore(NAutoPtr<Node> node);
12     static NAutoPtr<Node> More(NAutoPtr<Node> node);
13     static NAutoPtr<Node> NewCh(WCHAR input);
14     static NAutoPtr<Node> NewStr(NWString input);
15
16     NWString Parser(NWString& input);
17
18     NAutoPtr<Fail>& Value();
19 protected:
20     NAutoPtr<Fail> left;
21 };

下面来分析一下Node里的函数:
+:对应于Seq,用于��两个Node�q�接��h��.
|:对应与Alt,用于选择两个Node.
-:只有left和right的Value()都是NAutoPtr时才可��?内部有类型�{�?表示从哪个字�W�到哪个字符.
OnceMore:重复1�ơ及以上.
More:重复0�ơ以�?
NewCh:生成一个NAutoPtr的Node对象.
NewStr:生成一个NAutoPtr的Node对象.

下面我们需�?个宏.

1 #define ONCEMORE(N)                    Node::OnceMore(N)
2 #define MORE(N)                        Node::More(N)
3 #define NEWCH(N)                    Node::NewCh(N)
4 #define NEWSTR(N)                    Node::NewStr(N)

�q?个宏仅�ؓ了输入方�?br>
然后我们来测试一�?

1     NAutoPtr<Node> Symbol = ONCEMORE(NEWCH('_') | NEWCH('a') - NEWCH('z')) | (NEWCH('A') - NEWCH('Z'))
2         + MORE(NEWCH('_') | (NEWCH('0') - NEWCH('9')) | (NEWCH('a') - NEWCH('z')) | (NEWCH('A') - NEWCH('Z')));
3     NAutoPtr<Node> Number = ONCEMORE(NEWCH('0') - NEWCH('9'));
4     NAutoPtr<Node> Real = Number + NEWCH('.') + Number;

�怿��Ҏ(gu��)��则表辑ּ�有一定认识的同学已经知道�q?条语句分别对应于什么正则表辑ּ�.
Symbol->[_a-zA-Z]+[_0-9a-zA-Z]*
Number->[0-9]+
Real->[0-9]+.[0-9]+

定义一个待分析的字�W�串.

1 NWString str = L"abcce_fg123.459agetr";

对其分析.

1     wprintf(L"%s\n",str);
2     wprintf(L"%s\n",Symbol->Parser(str));
3     wprintf(L"%s\n",Real->Parser(str));
4     wprintf(L"%s\n",Symbol->Parser(str));

分析�l�果.

1 abcce_fg123.459agetr
2 123.459agetr
3 agetr
4

因�ؓ没有考虑分析效率问题,所以��用NWString作�ؓ输入和输�?在实际��用中可用LPTSTR来代替NWString,同时修改响应代码.
最后给�?a href="http://www.shnenglu.com/Files/lwch/RegexEngine.rar">源代�?/a>

lwch 2011-01-26 22:11 发表评论

lwch — Sat, 22 Jan 2011 09:11:00 GMT

摘要: 本文的思�\来源于http://www.shnenglu.com/vczh/archive/2008/05/21/50656.html首先先看代码: 1 #include 2 3 class Element 4 {&n... 阅读全文

lwch 2011-01-22 17:11 发表评论

NScript部分数据�l�构

lwch — Fri, 14 Jan 2011 08:00:00 GMT

下面来分析一�?a target=_blank>NScript的部分数据结�?br>

1     class SyntaxNode
2     {
3     public:
4         int Op1;
5         int Op2;
6         List<NAutoPtr<SyntaxNode>> Child;
7
8         SyntaxNode(int O1,int O2) : Op1(O1),Op2(O2){}
9     };
10
11     class CharClass
12     {
13     public:
14         int Index;
15         NWString String;
16
17         CharClass(NWString S) : String(S){}
18     };

每个语法树的节点�?个参数Op1,Op2分别表示当前节点的类型和附加参数
Child为当前节点的子节�?br>
CharClass�l�构则比较简单分别�ؓ索引和字�W?br>
然后是部分SyntaxNode的Op1的枚�?

1     enum OpCode_Type
2     {
3         opNull,
4         opVar,
5         opConst,
6     };

以及VarType的枚�?

1     enum Var_Type
2     {
3         vtNull,
4         vtVoid,
5         vtBool,
6         vtInt,
7         vtReal,
8         vtString,
9         vtSymbol,
10     };

和��生式索引的宏定义:

1     #define INDEX_VARTYPE_VOID                1
2     #define INDEX_VARTYPE_BOOL                2
3     #define INDEX_VARTYPE_INT                3
4     #define INDEX_VARTYPE_REAL                4
5     #define INDEX_VARTYPE_STRING            5
6     #define INDEX_VALUETYPE_STRING            6
7     #define INDEX_VALUETYPE_SYMBOL            7
8     #define INDEX_VALUETYPE_REAL            8
9     #define INDEX_VALUETYPE_DIGIT            9
10     #define INDEX_VALUETYPE_TRUE            10
11     #define INDEX_VALUETYPE_FALSE            11

以上索引的定义取自NS.txt,随着以后文法的增加这里的索引定义也会增加
NS.h,NS.cpp,NS.ParserTable均是由NScriptMacro.exe�q�行NS.txt生成�?br>
下面来看一下SyntaxAnalyze函数:

1 BOOL NSyntax::SyntaxAnalyze(int i)
2 {
3     BOOL bResult = TRUE;
4     // �Ҏ(gu��)��产生式烦引生成语法树
5     switch(i)
6     {
7     case INDEX_VARTYPE_VOID:
8     case INDEX_VARTYPE_BOOL:
9     case INDEX_VARTYPE_INT:
10     case INDEX_VARTYPE_REAL:
11     case INDEX_VARTYPE_STRING:
12         bResult = VarType(i);
13         break;
14     case INDEX_VALUETYPE_STRING:
15     case INDEX_VALUETYPE_SYMBOL:
16     case INDEX_VALUETYPE_REAL:
17     case INDEX_VALUETYPE_DIGIT:
18     case INDEX_VALUETYPE_TRUE:
19     case INDEX_VALUETYPE_FALSE:
20         bResult = ValueType(i);
21         break;
22     }
23     return bResult;
24 }

�q�个函数�Ҏ(gu��)��传入参数(产生式烦�?调用相关函数生成语法�?具体语法树的生成�q�程��L(f��ng)��相关代码

lwch 2011-01-14 16:00 发表评论

开源编译器��目NScript

lwch — Thu, 13 Jan 2011 13:38:00 GMT

��目地址

最初文法定义�ؓ:

1 %token "void" "bool" "int" "real" "string";
2 %token "true" "false";
3 %token "{" "}" "," ";" "=";
4 %token "+" "-" "*" "/";
5 %token ">" "<" ">=" "<=" "==" "and" "not" "or";
6
7 %start program;
8
9 var_type    ->    "void"
10             |    "bool"
11             |    "int"
12             |    "real"
13             |    "string"
14             ;
15
16 value_type    ->    "{String}"
17             |    "{Symbol}"
18             |    "{real}"
19             |    "{digit}"
20             |    "true"
21             |    "false"
22             ;
23
24 paramter_define_desc    ->    "{LQ}" paramter_defines "{RQ}"
25                         |    "{LQ}" "{RQ}"
26                         ;
27
28 paramter_defines    ->    paramter_defines "," paramter_one
29                     |    paramter_one
30                     ;
31
32 paramter_one        ->    var_type "{Symbol}"
33                     ;
34
35 assign_type            ->    "{Symbol}"
36                     ;
37
38 program        ->    item_list
39             ;
40
41 item_list    ->    item_list item
42             |    item
43             ;
44
45 item        ->    function
46             |    define_desc ";"
47             ;
48
49 stmt_list    ->    stmt_list stmt
50             |    stmt
51             ;
52
53 stmt        ->    define_desc ";"
54             |    assign_desc ";"
55             |    ";"
56             ;
57
58 function    ->    var_type "{Symbol}" paramter_define_desc "{" stmt_list "}"
59             |    var_type "{Symbol}" paramter_define_desc "{" "}"
60             ;
61
62 define_desc    ->    define_desc "," "{Symbol}"
63             |    var_type "{Symbol}"
64             ;
65
66 assign_desc    ->    assign_type "=" exp
67             ;
68
69 exp        ->    exp ">" exp1
70         |    exp "<" exp1
71         |    exp ">=" exp1
72         |    exp "<=" exp1
73         |    exp "==" exp1
74         |    exp "and" exp1
75         |    exp "or" exp1
76         |    "not" exp1
77         |    "+" exp1
78         |    "-" exp1
79         |    exp1
80         ;
81
82 exp1        ->    exp1 "+" exp2
83         |    exp1 "-" exp2
84         |    exp2
85         ;
86
87 exp2        ->    exp2 "*" exp3
88         |    exp2 "/" exp3
89         |    exp3
90         ;
91
92 exp3        ->    "{LQ}" exp "{RQ}"
93         |    value_type
94         ;

�׃��上文法中仅有函数的定义和变量的定�?br>有点�c�C的味�?
已成功将ESLanguage大部分代码移植到�q�个��目�?

lwch 2011-01-13 21:38 发表评论

已完成语法分析器

lwch — Mon, 30 Aug 2010 09:29:00 GMT

分析器文�?

1 %token    "%token" "%start"                ;
2 %token    ";" "->" "|"                    ;
3
4 %start program                        ;
5
6 program        ->    item_list
7         ;
8
9 item_list    ->    item_list item
10         |    item
11         ;
12
13 item        ->    token_def ";"
14         |    start_def ";"
15         |    rule_def ";"
16         |    ";"
17         ;
18
19 token_def    ->    token_def "{String}"
20         |    "%token" "{String}"
21         ;
22
23 start_def    ->    "%start" "{Symbol}"
24         ;
25
26 rule_def    ->    "{Symbol}" "->" rhs_list
27         ;
28
29 rhs_list    ->    rhs_list "|" rhs
30         |    rhs
31         ;
32
33 rhs        ->    rhs "{String}"
34         |    rhs "{Symbol}"
35         |    "{String}"
36         |    "{Symbol}"
37         ;
38

NScriptMacro
主要用来��给定的文法文�g转化为LALR(1)分析�?生成的cpp和h文�g可��用分析器分析,out文�g是语法分析表
里面有个��单的CMinus的例�?

lwch 2010-08-30 17:29 发表评论

lwch — Sat, 28 Aug 2010 07:28:00 GMT

对于�l�定文法文�g:

1 %token "if" "then" "else" "end" ;
2 %token "st" ;
3 %token "+" "*" ;
4
5 %start program ;
6
7 program        ->    if_stmt
8         ;
9
10 if_stmt        ->    "if" exp "then" stmt "end"
11         |    "if" exp "then" stmt "else" stmt "end"
12         ;
13
14 exp        ->    exp1
15         ;
16
17 exp1        ->    exp1 "+" exp2
18         |    exp2
19         ;
20
21 exp2        ->    exp2 "*" exp3
22         |    exp3
23         ;
24
25 exp3        ->    "{LQ}" exp1 "{RQ}"
26         |    "{digit}"
27         ;
28
29 stmt        ->    "st"
30         ;

生成分析表得:

lwch 2010-08-28 15:28 发表评论

修改分析器的分析器的语法

lwch — Sat, 28 Aug 2010 07:23:00 GMT

去除了letter定义,暂时�q�不支持正则表达�?.

lwch 2010-08-28 15:23 发表评论

我的语法分析器的分析器的基本语法和分析表

lwch — Tue, 03 Aug 2010 12:21:00 GMT

基本语法:

1 %token    "%token" "%letter" "%start"            ;
2 %token    ":" ";" "->" "|"                ;
3
4 %letter string    :    "{string}"            ;
5 %letter symbol    :    "{symbol}"            ;
6
7 %start program                        ;
8
9 string_list    ->    string_list string
10         |    string
11         ;
12
13 symbol_list    ->    symbol_list symbol
14         |    symbol
15         ;
16
17 program        ->    item_list
18         ;
19
20 item_list    ->    item_list item
21         |    item
22         ;
23
24 item        ->    token_def ";"
25         |    letter_def ";"
26         |    start_def ";"
27         |    rule_def ";"
28         |    ";"
29         ;
30
31 token_def    ->    "%token" string_list
32         ;
33
34 letter_def    ->    "%letter" symbol ":" string_list
35         ;
36
37 start_def    ->    "%start" symbol
38         ;
39
40 rule_def    ->    symbol "->" rhs_list
41         ;
42
43 rhs_list    ->    rhs_list "|" rhs
44         |    rhs
45         ;
46
47 rhs        ->    term_list
48         ;
49
50 term_list    ->    term_list string
51         |    term_list symbol
52         |    string
53         |    symbol
54         ;

生成的分析表:
�׃��状态数量和非终�l�符数量�q�多,所以给出文�?a href="http://www.shnenglu.com/Files/lwch/ParserTable001.txt">《分析表�?/a>

下面是四则�؜合运��的文法文�g:

1 %token "+" "-"                ;
2 %token "*" "/"                ;
3 %token "(" ")"                ;
4
5 %letter AddOp    :    "+" "-"        ;
6 %letter MulOp    :    "*" "/"        ;
7 %letter ID    :    "{digit}"    ;
8 %letter LQ    :    "("        ;
9 %letter RQ    :    ")"        ;
10
11 %start Program                ;
12
13 Program        ->    Exp
14         ;
15
16 Exp        ->    Exp AddOp Term
17         |    Term
18         ;
19
20 Term        ->    Term MulOp Factor
21         |    Factor
22         ;
23
24 Factor        ->    LQ Exp RQ
25         |    ID
26         ;

lwch 2010-08-03 20:21 发表评论

已实��C��语法树到四元码的生成

lwch — Sat, 31 Jul 2010 17:05:00 GMT

对于�l�定表达�?
123 * 567 + 456 * (789 + 456)
生成四元码得:

对于表达�?
123 + 456 * (789 + 456) / 123 + 789
生成四元码得:

lwch 2010-08-01 01:05 发表评论

已实��C��个四则�؜合运��分析器

lwch — Mon, 26 Jul 2010 03:41:00 GMT

对于式子:10 + (5 + 9) / 3 - 7 * 3
求解�q�程如下:

主要在规�U�过�E�中增加了调用相兌��义处理函数来实现计算.

lwch 2010-07-26 11:41 发表评论

lwch — Sat, 24 Jul 2010 15:35:00 GMT

lwch 2010-07-24 23:35 发表评论

Precept和NV�cȝ��装

lwch — Thu, 22 Jul 2010 15:23:00 GMT

摘要: 1 #pragma once 2 #include "..\String\NWString.h" 3 #include "..\AutoPtr\AutoPtr.h" 4 #include "..\Common\List.h"&nb... 阅读全文

lwch 2010-07-22 23:23 发表评论

lwch — Thu, 22 Jul 2010 07:04:00 GMT

1.对于典型的if-else二义性文�?存在�U�进-接受(�U�进-归约)冲突,在我的LALR分析器中采用了和YACC相同的方�?首先处理�U�进操作.�q�样��可消除if-else的二义�?
if-else文法:
S->iEStS
S->iES
S->s
E->e
说明:
i代表if
s代表stmt
e代表exp
t代表else
对于以上文法生成的LALR(1)分析表�ؓ:

对于if exp stmt语句分析�l�果�?

对于if exp stmt else stmt语句分析�l�果�?

对于if exp if exp stmt语句分析�l�果�?

对于if exp if exp stmt else stmt语句分析�l�果�?

2.众所周知LALR文法同样存在归约-归约冲突,在我的LALR分析器中使用先书写的产生式进行归�U?
对于�l�定的存在归�U?归约冲突的文�?
S->T
S->i
T->i

生成LALR(1)分析表�ؓ:

分析输入串i的过�E��ؓ:

以上��是我的LALR(1)分析器处理冲�H�的�Ҏ(gu��)��?
下面逐步对这个分析器�q�行扩充,以实��C��个能自由输入文法的分析器.

lwch 2010-07-22 15:04 发表评论

lwch — Wed, 21 Jul 2010 12:24:00 GMT

对于�l�定文法:
E->E+T
E->E-T
E->T
T->T*F
T->T/F
T->F
F->(E)
F->i
生成LALR(1)分析表�ؓ:

�Ҏ(gu��)��定串:(i+i)*i�?i+i)*分别分析后得�?br>

虽说打印的时候没寚w��,但结果是对的..

lwch 2010-07-21 20:24 发表评论

lwch — Sun, 18 Jul 2010 10:02:00 GMT

分析�?/a>

LR��目内有一宏定义可定义为LR0或SLR1
LR1分析器分析速度�q�慢有待优化..
求Follow集用了非递归��法,发现递归��法�Ҏ(gu��)��引�v无限循环.
希望�Ҏ(gu��)��在学习编译原理的同学有所启发.

lwch 2010-07-18 18:02 发表评论

已实现LR(1)分析表的自动创徏

lwch — Sat, 17 Jul 2010 05:59:00 GMT

对于�l�定文法:
E->E+T
E->E-T
E->T
T->T*F
T->T/F
T->F
F->(E)
F->i
生成LR(1)分析表得:

LR(1)分析表的��是无比的巨大啊...

lwch 2010-07-17 13:59 发表评论

lwch — Fri, 16 Jul 2010 08:03:00 GMT

对于�l�定文法:
E->E+T
E->E-T
E->T
T->T*F
T->T/F
T->F
F->(E)
F->i
生成DFA状态机�?

  1 该文法的拓展文法为：
  2 $->E
  3 E->E+T
  4 E->E-T
  5 E->T
  6 T->T*F
  7 T->T/F
  8 T->F
  9 F->(E)
10 F->i
11 该文法的��目如下�Q?br> 12 (1) $->.E,#
13 (2) E->.E+T,#
14 (3) E->.E-T,#
15 (4) E->.T,#
16 (5) E->.E+T,+
17 (6) E->.E-T,+
18 (7) E->.T,+
19 (8) E->.E+T,-
20 (9) E->.E-T,-
21 (10) E->.T,-
22 (11) T->.T*F,#
23 (12) T->.T/F,#
24 (13) T->.F,#
25 (14) T->.T*F,+
26 (15) T->.T/F,+
27 (16) T->.F,+
28 (17) T->.T*F,-
29 (18) T->.T/F,-
30 (19) T->.F,-
31 (20) T->.T*F,*
32 (21) T->.T/F,*
33 (22) T->.F,*
34 (23) T->.T*F,/
35 (24) T->.T/F,/
36 (25) T->.F,/
37 (26) F->.(E),#
38 (27) F->.i,#
39 (28) F->.(E),+
40 (29) F->.i,+
41 (30) F->.(E),-
42 (31) F->.i,-
43 (32) F->.(E),*
44 (33) F->.i,*
45 (34) F->.(E),/
46 (35) F->.i,/
47 (36) $->E.,#
48 (37) E->E.+T,#
49 (38) E->E.-T,#
50 (39) E->E.+T,+
51 (40) E->E.-T,+
52 (41) E->E.+T,-
53 (42) E->E.-T,-
54 (43) E->T.,#
55 (44) E->T.,+
56 (45) E->T.,-
57 (46) T->T.*F,#
58 (47) T->T./F,#
59 (48) T->T.*F,+
60 (49) T->T./F,+
61 (50) T->T.*F,-
62 (51) T->T./F,-
63 (52) T->T.*F,*
64 (53) T->T./F,*
65 (54) T->T.*F,/
66 (55) T->T./F,/
67 (56) T->F.,#
68 (57) T->F.,+
69 (58) T->F.,-
70 (59) T->F.,*
71 (60) T->F.,/
72 (61) F->(.E),#
73 (62) E->.E+T,)
74 (63) E->.E-T,)
75 (64) E->.T,)
76 (65) T->.T*F,)
77 (66) T->.T/F,)
78 (67) T->.F,)
79 (68) F->.(E),)
80 (69) F->.i,)
81 (70) F->(.E),+
82 (71) F->(.E),-
83 (72) F->(.E),*
84 (73) F->(.E),/
85 (74) F->i.,#
86 (75) F->i.,+
87 (76) F->i.,-
88 (77) F->i.,*
89 (78) F->i.,/
90 (79) E->E+.T,#
91 (80) E->E+.T,+
92 (81) E->E+.T,-
93 (82) E->E-.T,#
94 (83) E->E-.T,+
95 (84) E->E-.T,-
96 (85) T->T*.F,#
97 (86) T->T*.F,+
98 (87) T->T*.F,-
99 (88) T->T*.F,*
100 (89) T->T*.F,/
101 (90) T->T/.F,#
102 (91) T->T/.F,+
103 (92) T->T/.F,-
104 (93) T->T/.F,*
105 (94) T->T/.F,/
106 (95) F->(E.),#
107 (96) E->E.+T,)
108 (97) E->E.-T,)
109 (98) F->(E.),+
110 (99) F->(E.),-
111 (100) F->(E.),*
112 (101) F->(E.),/
113 (102) E->T.,)
114 (103) T->T.*F,)
115 (104) T->T./F,)
116 (105) T->F.,)
117 (106) F->(.E),)
118 (107) F->i.,)
119 (108) E->E+T.,#
120 (109) E->E+T.,+
121 (110) E->E+T.,-
122 (111) E->E-T.,#
123 (112) E->E-T.,+
124 (113) E->E-T.,-
125 (114) T->T*F.,#
126 (115) T->T*F.,+
127 (116) T->T*F.,-
128 (117) T->T*F.,*
129 (118) T->T*F.,/
130 (119) T->T/F.,#
131 (120) T->T/F.,+
132 (121) T->T/F.,-
133 (122) T->T/F.,*
134 (123) T->T/F.,/
135 (124) F->(E).,#
136 (125) F->(E).,+
137 (126) F->(E).,-
138 (127) F->(E).,*
139 (128) F->(E).,/
140 (129) E->E+.T,)
141 (130) E->E-.T,)
142 (131) T->T*.F,)
143 (132) T->T/.F,)
144 (133) F->(E.),)
145 (134) E->E+T.,)
146 (135) E->E-T.,)
147 (136) T->T*F.,)
148 (137) T->T/F.,)
149 (138) F->(E).,)
150 ��目规范族如下：
151 I0 { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 }
152 I1 { 36, 37, 38, 39, 40, 41, 42 }
153 I2 { 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55 }
154 I3 { 56, 57, 58, 59, 60 }
155 I4 { 61, 62, 63, 64, 5, 6, 7, 8, 9, 10, 65, 66, 67, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 68, 69, 28, 29, 30, 31, 32, 33, 34, 35, 70, 71, 72, 73 }
156 I5 { 74, 75, 76, 77, 78 }
157 I6 { 79, 11, 12, 13, 20, 21, 22, 23, 24, 25, 26, 27, 32, 33, 34, 35, 80, 14, 15, 16, 28, 29, 81, 17, 18, 19, 30, 31 }
158 I7 { 82, 11, 12, 13, 20, 21, 22, 23, 24, 25, 26, 27, 32, 33, 34, 35, 83, 14, 15, 16, 28, 29, 84, 17, 18, 19, 30, 31 }
159 I8 { 85, 26, 27, 86, 28, 29, 87, 30, 31, 88, 32, 33, 89, 34, 35 }
160 I9 { 90, 26, 27, 91, 28, 29, 92, 30, 31, 93, 32, 33, 94, 34, 35 }
161 I10 { 95, 96, 97, 39, 40, 41, 42, 98, 99, 100, 101 }
162 I11 { 102, 44, 45, 103, 104, 48, 49, 50, 51, 52, 53, 54, 55 }
163 I12 { 105, 57, 58, 59, 60 }
164 I13 { 106, 62, 63, 64, 5, 6, 7, 8, 9, 10, 65, 66, 67, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 68, 69, 28, 29, 30, 31, 32, 33, 34, 35, 70, 71, 72, 73 }
165 I14 { 107, 75, 76, 77, 78 }
166 I15 { 108, 46, 47, 52, 53, 54, 55, 109, 48, 49, 110, 50, 51 }
167 I16 { 56, 59, 60, 57, 58 }
168 I17 { 61, 62, 63, 64, 5, 6, 7, 8, 9, 10, 65, 66, 67, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 68, 69, 28, 29, 30, 31, 32, 33, 34, 35, 72, 73, 70, 71 }
169 I18 { 74, 77, 78, 75, 76 }
170 I19 { 111, 46, 47, 52, 53, 54, 55, 112, 48, 49, 113, 50, 51 }
171 I20 { 114, 115, 116, 117, 118 }
172 I21 { 119, 120, 121, 122, 123 }
173 I22 { 124, 125, 126, 127, 128 }
174 I23 { 129, 65, 66, 67, 20, 21, 22, 23, 24, 25, 68, 69, 32, 33, 34, 35, 80, 14, 15, 16, 28, 29, 81, 17, 18, 19, 30, 31 }
175 I24 { 130, 65, 66, 67, 20, 21, 22, 23, 24, 25, 68, 69, 32, 33, 34, 35, 83, 14, 15, 16, 28, 29, 84, 17, 18, 19, 30, 31 }
176 I25 { 131, 68, 69, 86, 28, 29, 87, 30, 31, 88, 32, 33, 89, 34, 35 }
177 I26 { 132, 68, 69, 91, 28, 29, 92, 30, 31, 93, 32, 33, 94, 34, 35 }
178 I27 { 133, 96, 97, 39, 40, 41, 42, 98, 99, 100, 101 }
179 I28 { 85, 26, 27, 88, 32, 33, 89, 34, 35, 86, 28, 29, 87, 30, 31 }
180 I29 { 90, 26, 27, 93, 32, 33, 94, 34, 35, 91, 28, 29, 92, 30, 31 }
181 I30 { 95, 96, 97, 39, 40, 41, 42, 100, 101, 98, 99 }
182 I31 { 134, 103, 104, 52, 53, 54, 55, 109, 48, 49, 110, 50, 51 }
183 I32 { 105, 59, 60, 57, 58 }
184 I33 { 106, 62, 63, 64, 5, 6, 7, 8, 9, 10, 65, 66, 67, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 68, 69, 28, 29, 30, 31, 32, 33, 34, 35, 72, 73, 70, 71 }
185 I34 { 107, 77, 78, 75, 76 }
186 I35 { 135, 103, 104, 52, 53, 54, 55, 112, 48, 49, 113, 50, 51 }
187 I36 { 136, 115, 116, 117, 118 }
188 I37 { 137, 120, 121, 122, 123 }
189 I38 { 138, 125, 126, 127, 128 }
190 I39 { 114, 117, 118, 115, 116 }
191 I40 { 119, 122, 123, 120, 121 }
192 I41 { 124, 127, 128, 125, 126 }
193 I42 { 131, 68, 69, 88, 32, 33, 89, 34, 35, 86, 28, 29, 87, 30, 31 }
194 I43 { 132, 68, 69, 93, 32, 33, 94, 34, 35, 91, 28, 29, 92, 30, 31 }
195 I44 { 133, 96, 97, 39, 40, 41, 42, 100, 101, 98, 99 }
196 I45 { 136, 117, 118, 115, 116 }
197 I46 { 137, 122, 123, 120, 121 }
198 I47 { 138, 127, 128, 125, 126 }
199 状态�{�U�表如下�Q?br>200 I0 -> I1 [ E ]
201 I0 -> I2 [ T ]
202 I0 -> I3 [ F ]
203 I0 -> I4 [ ( ]
204 I0 -> I5 [ i ]
205 I1 -> I6 [ + ]
206 I1 -> I7 [ - ]
207 I2 -> I8 [ * ]
208 I2 -> I9 [ / ]
209 I4 -> I10 [ E ]
210 I4 -> I11 [ T ]
211 I4 -> I12 [ F ]
212 I4 -> I13 [ ( ]
213 I4 -> I14 [ i ]
214 I6 -> I15 [ T ]
215 I6 -> I16 [ F ]
216 I6 -> I17 [ ( ]
217 I6 -> I18 [ i ]
218 I7 -> I19 [ T ]
219 I7 -> I16 [ F ]
220 I7 -> I17 [ ( ]
221 I7 -> I18 [ i ]
222 I8 -> I20 [ F ]
223 I8 -> I4 [ ( ]
224 I8 -> I5 [ i ]
225 I9 -> I21 [ F ]
226 I9 -> I4 [ ( ]
227 I9 -> I5 [ i ]
228 I10 -> I22 [ ) ]
229 I10 -> I23 [ + ]
230 I10 -> I24 [ - ]
231 I11 -> I25 [ * ]
232 I11 -> I26 [ / ]
233 I13 -> I27 [ E ]
234 I13 -> I11 [ T ]
235 I13 -> I12 [ F ]
236 I13 -> I13 [ ( ]
237 I13 -> I14 [ i ]
238 I15 -> I28 [ * ]
239 I15 -> I29 [ / ]
240 I17 -> I30 [ E ]
241 I17 -> I11 [ T ]
242 I17 -> I12 [ F ]
243 I17 -> I13 [ ( ]
244 I17 -> I14 [ i ]
245 I19 -> I28 [ * ]
246 I19 -> I29 [ / ]
247 I23 -> I31 [ T ]
248 I23 -> I32 [ F ]
249 I23 -> I33 [ ( ]
250 I23 -> I34 [ i ]
251 I24 -> I35 [ T ]
252 I24 -> I32 [ F ]
253 I24 -> I33 [ ( ]
254 I24 -> I34 [ i ]
255 I25 -> I36 [ F ]
256 I25 -> I13 [ ( ]
257 I25 -> I14 [ i ]
258 I26 -> I37 [ F ]
259 I26 -> I13 [ ( ]
260 I26 -> I14 [ i ]
261 I27 -> I38 [ ) ]
262 I27 -> I23 [ + ]
263 I27 -> I24 [ - ]
264 I28 -> I39 [ F ]
265 I28 -> I17 [ ( ]
266 I28 -> I18 [ i ]
267 I29 -> I40 [ F ]
268 I29 -> I17 [ ( ]
269 I29 -> I18 [ i ]
270 I30 -> I41 [ ) ]
271 I30 -> I23 [ + ]
272 I30 -> I24 [ - ]
273 I31 -> I42 [ * ]
274 I31 -> I43 [ / ]
275 I33 -> I44 [ E ]
276 I33 -> I11 [ T ]
277 I33 -> I12 [ F ]
278 I33 -> I13 [ ( ]
279 I33 -> I14 [ i ]
280 I35 -> I42 [ * ]
281 I35 -> I43 [ / ]
282 I42 -> I45 [ F ]
283 I42 -> I33 [ ( ]
284 I42 -> I34 [ i ]
285 I43 -> I46 [ F ]
286 I43 -> I33 [ ( ]
287 I43 -> I34 [ i ]
288 I44 -> I47 [ ) ]
289 I44 -> I23 [ + ]
290 I44 -> I24 [ - ]

由此可见LR(1)分析表会变得无比的巨�?

lwch 2010-07-16 16:03 发表评论

已实现SLR(1)分析表的自动创徏

lwch — Mon, 12 Jul 2010 16:00:00 GMT

对于�l�定二义性文�?
E->E+T
E->E-T
E->T
T->T*F
T->T/F
T->F
F->(E)
F->i
求得SLR(1)分析表�ؓ:

lwch 2010-07-13 00:00 发表评论

关于字符串操作的注意事项

lwch — Sun, 11 Jul 2010 10:38:00 GMT

首先我们探讨几个问题:
CString str = L"";
str += 'a' + L"a";
或str += L"a" + 'a';
分别会得��C��?
�{�案是一堆一��L(f��ng)��q��.
�q�是��Z��么呢?
�׃��q�算�W�的优先�U�的关系先计��?a' + L"a"或L"a" + 'a'当字�W�串与单个字�W�相加时�~�译器认为是��指针向后移�?a'(0x61)个字�?最后进入CString�?=�q�算�W�重载函�?�׃��传入的是一个字�W�串指针所以函��C��从L"a"+0x61的位�|�开始到\0�l�尾的所有字�W�连接到原字�W�后.应此也就出现了�ؕ码的情况.
解决�Ҏ(gu��)��:
CString str = L"";
str += CString('a') + L"a";
或str += CString(L"a") + 'a';
在做加法�q�算旉��会进入CString�?�q�算�W�的重蝲函数以得到正��的�l�果.

lwch 2010-07-11 18:38 发表评论

lwch — Sun, 11 Jul 2010 09:05:00 GMT

对于�l�定文法:
S->aAcBe
A->b
A->Ab
B->d
生成分析表得:

1 LR(0)分析表�ؓ�Q?br> 2     a    c    e    b    d    #    S    A    B
3 0    S2    ε    ε    ε    ε    ε    1    ε    ε
4 1    ε    ε    ε    ε    ε    acc    ε    ε    ε
5 2    ε    ε    ε    S4    ε    ε    ε    3    ε
6 3    ε    S5    ε    S6    ε    ε    ε    ε    ε
7 4    R2    R2    R2    R2    R2    R2    ε    ε    ε
8 5    ε    ε    ε    ε    S8    ε    ε    ε    7
9 6    R3    R3    R3    R3    R3    R3    ε    ε    ε
10 7    ε    ε    S9    ε    ε    ε    ε    ε    ε
11 8    R4    R4    R4    R4    R4    R4    ε    ε    ε
12 9    R1    R1    R1    R1    R1    R1    ε    ε    ε

lwch 2010-07-11 17:05 发表评论

lwch — Fri, 09 Jul 2010 09:45:00 GMT

对于�l�定文法:

exp->exp1

exp1->exp2 | exp5

exp5->exp1 (“<” | “>” | “==”) exp2

exp2->exp3 | exp6

exp6->exp2 (“+” | “-“) exp3

exp3->exp4 | exp7

exp7->exp3(“*” | “/”) exp4

exp4->”(“ exp “)”

生成ε-Parser�?

1 ε- Parser:
2 Start:28
3 X:        Type        From        To
4 (:        0        0        1(finial)
5 ):        0        2        3(finial)
6 ε:        2        1(finial)        0
7 ε:        2        1(finial)        2
8 *:        0        4        5(finial)
9 /:        0        6        7(finial)
10 ε:        2        8        4
11 ε:        2        5(finial)        9(finial)
12 ε:        2        8        6
13 ε:        2        7(finial)        9(finial)
14 ε:        2        3(finial)        8
15 ε:        2        9(finial)        8
16 ε:        2        10        0
17 ε:        2        3(finial)        11(finial)
18 ε:        2        10        0
19 ε:        2        9(finial)        11(finial)
20 +:        0        12        13(finial)
21 -:        0        14        15(finial)
22 ε:        2        16        12
23 ε:        2        13(finial)        17(finial)
24 ε:        2        16        14
25 ε:        2        15(finial)        17(finial)
26 ε:        2        11(finial)        16
27 ε:        2        17(finial)        16
28 ε:        2        18        10
29 ε:        2        11(finial)        19(finial)
30 ε:        2        18        10
31 ε:        2        17(finial)        19(finial)
32 <:        0        20        21(finial)
33 >:        0        22        23(finial)
34 ==:        1        24        25(finial)
35 ε:        2        26        20
36 ε:        2        21(finial)        27(finial)
37 ε:        2        26        22
38 ε:        2        23(finial)        27(finial)
39 ε:        2        26        24
40 ε:        2        25(finial)        27(finial)
41 ε:        2        19(finial)        26
42 ε:        2        27(finial)        26
43 ε:        2        28        18
44 ε:        2        19(finial)        29(finial)
45 ε:        2        28        18
46 ε:        2        27(finial)        29(finial)

�~�点:必须手动生成文法�?
下一步是去除ε�?

lwch 2010-07-09 17:45 发表评论

用正则表辑ּ�构造词法分析器

lwch — Sat, 03 Jul 2010 10:14:00 GMT

《用正则表达式构造词法分析器�?/a>
�q�篇文章阐述了如何用正则表达式构造语法树�q�生�?#949;-NFA�Q�去�?#949;边�{换到NFA�Q�最后�{换到DFA的所有过�E�。学习编译原理的朋友们如果遇��C��么问题不妨看下这��文章�?
源码下蝲

lwch 2010-07-03 18:14 发表评论

lwch — Fri, 02 Jul 2010 16:21:00 GMT

�E�后制作相关文档..

  1Regex Expression:(ab|a[a-z0-9]+|cd)*
  2CharClassList:
  3*        0
  4|        1
  5a        2
  6b        3
  7+        4
  8a - z        5
  90 - 9        6
10c        7
11d        8
12
13ε-NFA:
14Start:26 End:26
15X:From    To
162:0        1
173:2        3
18ε:1        2
192:4        5
205:6        7
216:8        9
22ε:10        6
23ε:10        8
24ε:7        11
25ε:9        11
265:12        13
276:14        15
28ε:16        12
29ε:16        14
30ε:13        17
31ε:15        17
32ε:17        10
33ε:11        17
34ε:5        16
35ε:18        0
36ε:18        4
37ε:3        19
38ε:17        19
397:20        21
408:22        23
41ε:21        22
42ε:24        18
43ε:24        20
44ε:19        25
45ε:23        25
46ε:26        24
47ε:25        26
48
49NFA:
50Start:26
51X:From    To
527:26(finial)        21
532:26(finial)        1
542:26(finial)        5
553:1        3(finial)
567:3(finial)        21
572:3(finial)        1
582:3(finial)        5
595:5        13(finial)
606:5        15(finial)
615:7(finial)        7(finial)
626:7(finial)        9(finial)
637:7(finial)        21
642:7(finial)        1
652:7(finial)        5
665:9(finial)        7(finial)
676:9(finial)        9(finial)
687:9(finial)        21
692:9(finial)        1
702:9(finial)        5
715:13(finial)        7(finial)
726:13(finial)        9(finial)
737:13(finial)        21
742:13(finial)        1
752:13(finial)        5
765:15(finial)        7(finial)
776:15(finial)        9(finial)
787:15(finial)        21
792:15(finial)        1
802:15(finial)        5
818:21        23(finial)
827:23(finial)        21
832:23(finial)        1
842:23(finial)        5
85
86DFA:
87Start:26
88X:Froms        Tos
897:26 (finial)        21
902:26 (finial)        1 5
918:21         23 (finial)
923:1 5         3 (finial)
935:1 5         13 (finial)
946:1 5         15 (finial)
957:23 (finial)        21
962:23 (finial)        1 5
977:3 (finial)        21
982:3 (finial)        1 5
995:13 (finial)        7 (finial)
1006:13 (finial)        9 (finial)
1017:13 (finial)        21
1022:13 (finial)        1 5
1035:15 (finial)        7 (finial)
1046:15 (finial)        9 (finial)
1057:15 (finial)        21
1062:15 (finial)        1 5
1075:7 (finial)        7 (finial)
1086:7 (finial)        9 (finial)
1097:7 (finial)        21
1102:7 (finial)        1 5
1115:9 (finial)        7 (finial)
1126:9 (finial)        9 (finial)
1137:9 (finial)        21
1142:9 (finial)        1 5

lwch 2010-07-03 00:21 发表评论

NScript词法分析�?语法分析�?代码生成器已制作完成

lwch — Sat, 26 Jun 2010 02:57:00 GMT

�׃��未进行类型检查直接生成的虚拟��Z��码所以可以在代码中直接��用变�?
Do语句:

For语句:

Function:

If语句:

Local语句:

Switch语句:

While语句:

阶乘:

lwch 2010-06-26 10:57 发表评论

NScript部分文法

lwch — Sat, 26 Jun 2010 02:37:00 GMT

sym->[a-z|A-Z|_][a-z|A-Z|0-9|_]*

int->[0-9]+

real->[0-9]+.[0-9]+

string->

datatype->”int” | “real” | “bool” | “string”

prgama->function | functionheader “;”

functionheader->”function” sym ”(“ parameters ”)” [“as” datatype]

parameters->[[sym as datatype],parameters]

function->functionheader “{“ block “}”

block->statementlist

local-stmt->”local” varlist

varlist->symlist “as” datatype [“,” varlist]

if-stmt->”if” exp statementlist [“else” statementlist]

while-stmt->”while” exp statementlist

do-stmt->”do” statementlist “while” exp “;”

for-stmt->”for” “(“ exp “;” exp “;” exp “)” statementlist

switch-stmt->”switch” exp “{“ case-stmt “}”

case-stmt->(”case” sym | “default”) “:” statementlist case-stmt

assign-stmt->exp “=” exp

call-stmt->sym “(“ parameters “)” “;”

return-stmt->”return” exp

symlist->sym [“,” symlist]

statement->“{“ statementlist “}”

statement->”;”

statementlist->statement [statementlist]

exp->exp1

exp1->exp2

exp1->exp1 (“<” | “<=” | “=” | “>=” | “>” | “!=”) exp2

exp2->exp3

exp2->exp2 (“+” | “-“) exp3

exp3->exp4

exp3->exp3(“*” | “/”) exp4

exp4->”(“ exp “)”

lwch 2010-06-26 10:37 发表评论