INTERNATIONAL ISO/IEC STANDARD 23270 Third edition 2018-12 Information technology - Programming languages C# Technologies de I'information - Langages de programmation - C# Reference number IEC ISO/IEC 23270:2018(E) s @IS0/IEC 2018 IS0/IEC 23270:2018(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0/IEC 2018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below or Iso's member body in the country of the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0/IEC 2018 - All rights reserved ISO/IEC 23270:2018(E) Table of Contents Foreword , xix Introduction .xxi 1.Scope 2. Normative references 3. Terms and definitions. .5 4. Acronyms and abbreviations ... 5. General description... .9 6. Conformance . 11 7. Lexical structure. 7.1 Programs .... 7.2 Grammars..... 13 7.2.1 General... 13 7.2.2 Grammar notation ... 13 7.2.3 Lexical grammar ... 7.2.4 Syntactic grammar . 15 7.2.5 Grammar ambiguities . 7.3 Lexical analysis .... 16 7.3.1 General.... 16 7.3.2 Line terminators... 16 7.3.3 Comments.. 17 7.3.4 White space... 19 .19 7.4.2 Unicode character escape sequences... .19 7.4.3 Identifiers .... .20 7.4.4 Keywords... ..21 7.4.5 Literals... .22 7.4.5.1 General.. 7.4.5.2 Boolean literals. ..23 7.4.5.3 Integer literals . .23 7.4.5.4 Real literals.. .24 7.4.5.5 Character literals . .25 7.4.5.6 String literals .. 7.4.5.7 The null literai . 7.4.6 Operators and punctuators.... .28 7.5 Pre-processing directives .... .28 7.5.1 General... .28 7.5.2 Conditional compilation symbols... ...30 7.5.3 Pre-processing expressions.... 7.5.4Definitiondirectives 31 7.5.5 Conditional compilation directives . 32 @ISO/IEC 2018 - All rights reserved ili ISO/IEC 23270:2018(E) 7.5.6 Diagnostic directives . 7.5.7 Region directives.. 7.5.8 Line directives .35 7.5.9 Pragma directives... ..36 8. Basic concepts.. ..37 8.1 Application startup.... 8.2 Application termination ... ..38 8.3 Declarations.... .38 8.4 Members... 8.4.1 General.... .41 8.4.2 Namespace members .... 8.4.3 Struct members..... .41 8.4.4 Enumeration members .... ..42 8.4.5Classmembers .42 8.4.6 Interface members. 8.4.7 Array members... ...42 8.4.8 Delegate members. 8.5 Member access .42 8.5.1 General.. .42 8.5.2 Declared accessibility .... 42 8.5.3 Accessibility domains . 8.5.4 Protected access . .46 8.5.5 Accessibility constraints.... 8.6 Signatures and overloading.. .48 8.7 Scopes.... .49 8.7.1 General. .49 8.7.2 Name hiding . .52 8.7.2.1 General.. .52 8.7.2.2 Hiding through nesting.... 8.7.2.3 Hiding through inheritance ... .53 8.8 Namespace and type names . 54 8.8.1 General. .54 8.8.2 Unqualified names . ..56 8.8.3 Fully qualified names .... 8.10 Execution order... .59 9. Types.. ..61 . General... 9.2 Reference types.... 9.2.1 General.. .61 9.2.2 Class types.. .62 9.2.3 The object type .. ..62 9.2.4 The dynamic type.. 9.5 The string type .... 9.2.6 Interface types .... 9.2.7 Array types . .63 9.2.8 Delegate types . .63 9.3 Value types... .. 63 9.3.1 General... ..63 iv @ISO/IEC 2018 - All rights reserved ISO/IEC 23270:2018(E) 9.3.2 The System.ValueType type.... .64 9.3.3 Default constructors .64 9.3.4 Struct types ... ...65 9.3.5 Simple types.. 9.3.6 Integral types.... 9.3.7 Floating-point types ..... 9.3.8 The decimal type.. .68 9.3.9 The bool type .69 9.3.10 Enumeration types. ..69 9.3.11 Nullable value types... 9.3.12 Boxing and unboxing.... 9.4 Constructed types.... .70 9.4.1 General... .70 9.4.2 Type arguments . 71 9.4.3 Open and closed types... 71 9.4.4 Bound and unbound types.... 72 9.5 Type parameters .... 73 9.6 Expression