Table of Contents 1 страница

Language Specification

Version 4.0

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Table of Contents

1. Introduction.......................................................................................................................................... 1

1.1 Hello world......................................................................................................................................... 1

1.2 Program structure............................................................................................................................... 2

1.3 Types and variables............................................................................................................................. 4

1.4 Expressions......................................................................................................................................... 6

1.5 Statements.......................................................................................................................................... 8

1.6 Classes and objects............................................................................................................................ 12

1.6.1 Members.................................................................................................................................... 12

1.6.2 Accessibility................................................................................................................................ 13

1.6.3 Type parameters......................................................................................................................... 13

1.6.4 Base classes............................................................................................................................... 14

1.6.5 Fields.......................................................................................................................................... 14

1.6.6 Methods..................................................................................................................................... 15

1.6.6.1 Parameters........................................................................................................................... 15

1.6.6.2 Method body and local variables............................................................................................. 16

1.6.6.3 Static and instance methods................................................................................................... 17

1.6.6.4 Virtual, override, and abstract methods................................................................................... 18

1.6.6.5 Method overloading............................................................................................................... 20

1.6.7 Other function members.............................................................................................................. 21

1.6.7.1 Constructors......................................................................................................................... 22

1.6.7.2 Properties............................................................................................................................. 23

1.6.7.3 Indexers............................................................................................................................... 23

1.6.7.4 Events.................................................................................................................................. 24

1.6.7.5 Operators............................................................................................................................. 24

1.6.7.6 Destructors........................................................................................................................... 25

1.7 Structs.............................................................................................................................................. 25

1.8 Arrays.............................................................................................................................................. 26

1.9 Interfaces......................................................................................................................................... 27

1.10 Enums............................................................................................................................................. 29

1.11 Delegates........................................................................................................................................ 30

1.12 Attributes........................................................................................................................................ 31

2. Lexical structure................................................................................................................................. 33

2.1 Programs.......................................................................................................................................... 33

2.2 Grammars......................................................................................................................................... 33

2.2.1 Grammar notation........................................................................................................................ 33

2.2.2 Lexical grammar......................................................................................................................... 34

2.2.3 Syntactic grammar...................................................................................................................... 34

2.3 Lexical analysis................................................................................................................................. 34

2.3.1 Line terminators.......................................................................................................................... 35

2.3.2 Comments.................................................................................................................................. 35

2.3.3 White space................................................................................................................................ 37

2.4 Tokens.............................................................................................................................................. 37

2.4.1 Unicode character escape sequences........................................................................................... 37

2.4.2 Identifiers................................................................................................................................... 38

2.4.3 Keywords................................................................................................................................... 39

2.4.4 Literals....................................................................................................................................... 40

2.4.4.1 Boolean literals...................................................................................................................... 40

2.4.4.2 Integer literals....................................................................................................................... 40

2.4.4.3 Real literals........................................................................................................................... 41

2.4.4.4 Character literals................................................................................................................... 42

2.4.4.5 String literals......................................................................................................................... 43

2.4.4.6 The null literal....................................................................................................................... 45

2.4.5 Operators and punctuators........................................................................................................... 45

2.5 Pre-processing directives................................................................................................................... 45

2.5.1 Conditional compilation symbols.................................................................................................... 47

2.5.2 Pre-processing expressions.......................................................................................................... 47

2.5.3 Declaration directives.................................................................................................................. 48

2.5.4 Conditional compilation directives................................................................................................. 49

2.5.5 Diagnostic directives.................................................................................................................... 51

2.5.6 Region directives......................................................................................................................... 52

2.5.7 Line directives............................................................................................................................. 52

2.5.8 Pragma directives........................................................................................................................ 53

2.5.8.1 Pragma warning.................................................................................................................... 53

3. Basic concepts.................................................................................................................................... 55

3.1 Application Startup............................................................................................................................ 55

3.2 Application termination....................................................................................................................... 56

3.3 Declarations...................................................................................................................................... 56

3.4 Members.......................................................................................................................................... 58

3.4.1 Namespace members.................................................................................................................. 58

3.4.2 Struct members........................................................................................................................... 59

3.4.3 Enumeration members................................................................................................................. 59

3.4.4 Class members............................................................................................................................ 59

3.4.5 Interface members...................................................................................................................... 60

3.4.6 Array members........................................................................................................................... 60

3.4.7 Delegate members...................................................................................................................... 60

3.5 Member access................................................................................................................................. 60

3.5.1 Declared accessibility.................................................................................................................. 60

3.5.2 Accessibility domains................................................................................................................... 61

3.5.3 Protected access for instance members........................................................................................ 63

3.5.4 Accessibility constraints............................................................................................................... 64

3.6 Signatures and overloading................................................................................................................. 65

3.7 Scopes.............................................................................................................................................. 66

3.7.1 Name hiding................................................................................................................................ 69

3.7.1.1 Hiding through nesting........................................................................................................... 69

3.7.1.2 Hiding through inheritance...................................................................................................... 70

3.8 Namespace and type names............................................................................................................... 71

3.8.1 Fully qualified names................................................................................................................... 73

3.9 Automatic memory management........................................................................................................ 73

3.10 Execution order............................................................................................................................... 76

4. Types................................................................................................................................................... 77

4.1 Value types....................................................................................................................................... 77

4.1.1 The System.ValueType type........................................................................................................ 78

4.1.2 Default constructors.................................................................................................................... 78

4.1.3 Struct types................................................................................................................................. 79

4.1.4 Simple types................................................................................................................................ 79

4.1.5 Integral types.............................................................................................................................. 80

4.1.6 Floating point types...................................................................................................................... 81

4.1.7 The decimal type......................................................................................................................... 82

4.1.8 The bool type.............................................................................................................................. 83

4.1.9 Enumeration types....................................................................................................................... 83

4.1.10 Nullable types............................................................................................................................ 83

4.2 Reference types................................................................................................................................ 83

4.2.1 Class types................................................................................................................................. 84

4.2.2 The object type........................................................................................................................... 85

4.2.3 The dynamic type........................................................................................................................ 85

4.2.4 The string type............................................................................................................................ 85

4.2.5 Interface types............................................................................................................................ 85

4.2.6 Array types................................................................................................................................. 85

4.2.7 Delegate types............................................................................................................................ 85

4.3 Boxing and unboxing.......................................................................................................................... 86

4.3.1 Boxing conversions...................................................................................................................... 86

4.3.2 Unboxing conversions.................................................................................................................. 87

4.4 Constructed types.............................................................................................................................. 88

4.4.1 Type arguments.......................................................................................................................... 89

4.4.2 Open and closed types................................................................................................................. 89

4.4.3 Bound and unbound types............................................................................................................ 89

4.4.4 Satisfying constraints................................................................................................................... 89

4.5 Type parameters............................................................................................................................... 90

4.6 Expression tree types......................................................................................................................... 91

4.7 The dynamic type.............................................................................................................................. 92

5. Variables............................................................................................................................................. 93

5.1 Variable categories............................................................................................................................ 93

5.1.1 Static variables............................................................................................................................ 93

5.1.2 Instance variables........................................................................................................................ 93

5.1.2.1 Instance variables in classes................................................................................................... 93

5.1.2.2 Instance variables in structs................................................................................................... 94

5.1.3 Array elements........................................................................................................................... 94

5.1.4 Value parameters........................................................................................................................ 94

5.1.5 Reference parameters................................................................................................................. 94

5.1.6 Output parameters....................................................................................................................... 94

5.1.7 Local variables............................................................................................................................ 95

5.2 Default values................................................................................................................................... 96

5.3 Definite assignment........................................................................................................................... 96

5.3.1 Initially assigned variables............................................................................................................ 97

5.3.2 Initially unassigned variables......................................................................................................... 97

5.3.3 Precise rules for determining definite assignment........................................................................... 97

5.3.3.1 General rules for statements................................................................................................... 98

5.3.3.2 Block statements, checked, and unchecked statements............................................................ 98

5.3.3.3 Expression statements........................................................................................................... 98

5.3.3.4 Declaration statements.......................................................................................................... 98

5.3.3.5 If statements......................................................................................................................... 98

5.3.3.6 Switch statements................................................................................................................. 99

5.3.3.7 While statements................................................................................................................... 99

5.3.3.8 Do statements....................................................................................................................... 99

5.3.3.9 For statements..................................................................................................................... 100

5.3.3.10 Break, continue, and goto statements................................................................................... 100

5.3.3.11 Throw statements.............................................................................................................. 100

5.3.3.12 Return statements.............................................................................................................. 100

5.3.3.13 Try-catch statements......................................................................................................... 100

5.3.3.14 Try-finally statements......................................................................................................... 101

5.3.3.15 Try-catch-finally statements............................................................................................... 101

5.3.3.16 Foreach statements............................................................................................................ 102

5.3.3.17 Using statements............................................................................................................... 102

5.3.3.18 Lock statements................................................................................................................ 102

5.3.3.19 Yield statements................................................................................................................ 103

5.3.3.20 General rules for simple expressions.................................................................................... 103

5.3.3.21 General rules for expressions with embedded expressions..................................................... 103

5.3.3.22 Invocation expressions and object creation expressions......................................................... 103

5.3.3.23 Simple assignment expressions............................................................................................ 104

5.3.3.24 && expressions................................................................................................................. 104

5.3.3.25 || expressions..................................................................................................................... 105

5.3.3.26! expressions..................................................................................................................... 106

5.3.3.27?? expressions................................................................................................................... 106

5.3.3.28?: expressions.................................................................................................................... 106

5.3.3.29 Anonymous functions......................................................................................................... 107

5.4 Variable references......................................................................................................................... 107

5.5 Atomicity of variable references....................................................................................................... 107

6. Conversions...................................................................................................................................... 109

6.1 Implicit conversions.......................................................................................................................... 109

6.1.1 Identity conversion..................................................................................................................... 109

6.1.2 Implicit numeric conversions....................................................................................................... 110

6.1.3 Implicit enumeration conversions................................................................................................ 110

6.1.4 Implicit nullable conversions....................................................................................................... 110

6.1.5 Null literal conversions............................................................................................................... 111

6.1.6 Implicit reference conversions.................................................................................................... 111

6.1.7 Boxing conversions.................................................................................................................... 111

6.1.8 Implicit dynamic conversions...................................................................................................... 112

6.1.9 Implicit constant expression conversions...................................................................................... 112

6.1.10 Implicit conversions involving type parameters........................................................................... 112

6.1.11 User-defined implicit conversions.............................................................................................. 113

6.1.12 Anonymous function conversions and method group conversions................................................. 113

6.2 Explicit conversions.......................................................................................................................... 113

6.2.1 Explicit numeric conversions....................................................................................................... 114

6.2.2 Explicit enumeration conversions................................................................................................ 115

6.2.3 Explicit nullable conversions....................................................................................................... 115

6.2.4 Explicit reference conversions.................................................................................................... 116

6.2.5 Unboxing conversions................................................................................................................ 117

6.2.6 Explicit dynamic conversions...................................................................................................... 117

6.2.7 Explicit conversions involving type parameters............................................................................. 118

6.2.8 User-defined explicit conversions................................................................................................ 119

6.3 Standard conversions....................................................................................................................... 119

6.3.1 Standard implicit conversions...................................................................................................... 119