oSIST ISO/IEC DIS 8652:2021

INTERNATIONAL ISO/IEC
STANDARD 8652
Fourth edition
2023-05
Information technology —
Programming languages — Ada
Technologies de l'information — Langages de programmation — Ada
Reference number
© ISO/IEC 2023
© ISO/IEC 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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© ISO/IEC 2023 – All rights reserved

Contents
Foreword . xiii
Introduction . xv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
3.1 Types, objects, and their properties . 2
3.2 Subprograms and their properties . 7
3.3 Other syntactic constructs . 7
3.4 Runtime actions . 10
3.5 Exceptional situations . 10
4 General . 11
4.1 Structure . 11
4.2 Conformity of an Implementation . 12
4.3 Method of Description and Syntax Notation . 14
4.4 Classification of Errors . 15
5 Lexical Elements . 16
5.1 Character Set . 16
5.2 Lexical Elements, Separators, and Delimiters . 18
5.3 Identifiers . 19
5.4 Numeric Literals . 20
5.4.1 Decimal Literals . 20
5.4.2 Based Literals . 21
5.5 Character Literals . 21
5.6 String Literals . 21
5.7 Comments . 22
5.8 Pragmas . 22
5.9 Reserved Words . 25
6 Declarations and Types . 25
6.1 Declarations . 25
6.2 Types and Subtypes . 27
6.2.1 Type Declarations. 28
6.2.2 Subtype Declarations . 29
6.2.3 Classification of Operations . 30
6.2.4 Subtype Predicates . 31
6.3 Objects and Named Numbers . 34
6.3.1 Object Declarations . 36
6.3.2 Number Declarations . 39
6.4 Derived Types and Classes . 39
6.4.1 Derivation Classes . 42
6.5 Scalar Types . 44
6.5.1 Enumeration Types . 47
6.5.2 Character Types . 48
6.5.3 Boolean Types . 49
6.5.4 Integer Types . 49
6.5.5 Operations of Discrete Types . 52
6.5.6 Real Types . 53
6.5.7 Floating Point Types . 54
© ISO/IEC 2023 – All rights reserved iii

6.5.8 Operations of Floating Point Types . 55
6.5.9 Fixed Point Types . 56
6.5.10 Operations of Fixed Point Types . 58
6.6 Array Types . 59
6.6.1 Index Constraints and Discrete Ranges . 61
6.6.2 Operations of Array Types . 62
6.6.3 String Types . 63
6.7 Discriminants . 63
6.7.1 Discriminant Constraints . 66
6.7.2 Operations of Discriminated Types . 67
6.8 Record Types . 67
6.8.1 Variant Parts and Discrete Choices . 70
6.9 Tagged Types and Type Extensions . 72
6.9.1 Type Extensions . 75
6.9.2 Dispatching Operations of Tagged Types . 76
6.9.3 Abstract Types and Subprograms . 79
6.9.4 Interface Types . 80
6.10 Access Types . 82
6.10.1 Incomplete Type Declarations . 85
6.10.2 Operations of Access Types . 87
6.11 Declarative Parts . 93
6.11.1 Completions of Declarations . 93
7 Names and Expressions . 94
7.1 Names . 94
7.1.1 Indexed Components . 95
7.1.2 Slices . 96
7.1.3 Selected Components . 97
7.1.4 Attributes . 99
7.1.5 User-Defined References . 100
7.1.6 User-Defined Indexing . 101
7.2 Literals . 103
7.2.1 User-Defined Literals . 104
7.3 Aggregates . 106
7.3.1 Record Aggregates . 106
7.3.2 Extension Aggregates . 108
7.3.3 Array Aggregates . 110
7.3.4 Delta Aggregates . 114
7.3.5 Container Aggregates . 115
7.4 Expressions . 121
7.5 Operators and Expression Evaluation . 123
7.5.1 Logical Operators and Short-circuit Control Forms . 124
7.5.2 Relational Operators and Membership Tests . 125
7.5.3 Binary Adding Operators . 128
7.5.4 Unary Adding Operators . 129
7.5.5 Multiplying Operators . 129
7.5.6 Highest Precedence Operators . 132
7.5.7 Conditional Expressions . 132
7.5.8 Quantified Expressions . 134
7.5.9 Declare Expressions . 135
7.5.10 Reduction Expressions . 136
7.6 Type Conversions. 139
7.7 Qualified Expressions . 144
7.8 Allocators .
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