C++ Annotations Version 10.0.0

Frank B. Brokken

Center of Information Technology,
University of Groningen
Nettelbosje 1,
P.O. Box 11044,
9700 CA Groningen
The Netherlands
Published at the University of Groningen
ISBN 90 367 0470 7

1994 - 2014

This document is intended for knowledgeable users of C (or any other language using a C-like grammar, like Perl or Java) who would like to know more about, or make the transition to, C++. This document is the main textbook for Frank's C++ programming courses, which are yearly organized at the University of Groningen. The C++ Annotations do not cover all aspects of C++, though. In particular, C++'s basic grammar is not covered when equal to C's grammar. Any basic book on C may be consulted to refresh that part of C++'s grammar.

If you want a hard-copy version of the C++ Annotations: printable versions are available in postscript, pdf and other formats in

http://sourceforge.net/projects/cppannotations/,
in files having names starting with cplusplus (A4 paper size). Files having names starting with `cplusplusus' are intended for the US legal paper size. The C++ Annotations are also available as a Kindle book.

The latest version of the C++ Annotations in html-format can be browsed at:

http://cppannotations.sourceforge.net/
and/or at
http://www.icce.rug.nl/documents/

Table of Contents

Chapter 1: Overview Of The Chapters

Chapter 2: Introduction

2.1: What's new in the C++ Annotations

2.2: C++'s history

2.2.1: History of the C++ Annotations
2.2.2: Compiling a C program using a C++ compiler
2.2.3: Compiling a C++ program
2.2.3.1: C++ under MS-Windows
2.2.3.2: Compiling a C++ source text
2.2.3.3: C++14

2.3: C++: advantages and claims

2.4: What is Object-Oriented Programming?

2.5: Differences between C and C++

2.5.1: The function `main'
2.5.2: End-of-line comment
2.5.3: Strict type checking
2.5.4: Function Overloading
2.5.5: Default function arguments
2.5.6: NULL-pointers vs. 0-pointers and nullptr
2.5.7: The `void' parameter list
2.5.8: The `#define __cplusplus'
2.5.9: Using standard C functions
2.5.10: Header files for both C and C++
2.5.11: Defining local variables
2.5.12: The keyword `typedef'
2.5.13: Functions as part of a struct

Chapter 3: A First Impression Of C++

3.1: Extensions to C

3.1.1: Namespaces
3.1.2: The scope resolution operator ::
3.1.3: Using the keyword `const'
3.1.4: `cout', `cin', and `cerr'

3.2: Functions as part of structs

3.2.1: Data hiding: public, private and class
3.2.2: Structs in C vs. structs in C++

3.3: More extensions to C

3.3.1: References
3.3.2: Rvalue References
3.3.3: Strongly typed enumerations
3.3.4: Initializer lists
3.3.5: Type inference using `auto'
3.3.6: Defining types and 'using' declarations
3.3.7: Range-based for-loops
3.3.8: Raw String Literals
3.3.9: Binary constants

3.4: New language-defined data types

3.4.1: The data type `bool'
3.4.2: The data type `wchar_t'
3.4.3: Unicode encoding
3.4.4: The data type `long long int'
3.4.5: The data type `size_t'

3.5: A new syntax for casts

3.5.1: The `static_cast'-operator
3.5.2: The `const_cast'-operator
3.5.3: The `reinterpret_cast'-operator
3.5.4: The `dynamic_cast'-operator
3.5.5: Casting 'shared_ptr' objects

3.6: Keywords and reserved names in C++

Chapter 4: Name Spaces

4.1: Namespaces

4.1.1: Defining namespaces
4.1.1.1: Declaring entities in namespaces
4.1.1.2: A closed namespace
4.1.2: Referring to entities
4.1.2.1: The `using' directive
4.1.2.2: `Koenig lookup'
4.1.3: The standard namespace
4.1.4: Nesting namespaces and namespace aliasing
4.1.4.1: Defining entities outside of their namespaces

Chapter 5: The `string' Data Type

5.1: Operations on strings

5.2: A std::string reference

5.2.1: Initializers
5.2.2: Iterators
5.2.3: Operators
5.2.4: Member functions
5.2.5: Conversion functions

Chapter 6: The IO-stream Library

6.1: Special header files

6.2: The foundation: the class `ios_base'

6.3: Interfacing `streambuf' objects: the class `ios'

6.3.1: Condition states
6.3.2: Formatting output and input
6.3.2.1: Format modifying member functions
6.3.2.2: Formatting flags

6.4: Output

6.4.1: Basic output: the class `ostream'
6.4.1.1: Writing to `ostream' objects
6.4.1.2: `ostream' positioning
6.4.1.3: `ostream' flushing
6.4.2: Output to files: the class `ofstream'
6.4.2.1: Modes for opening stream objects
6.4.3: Output to memory: the class `ostringstream'

6.5: Input

6.5.1: Basic input: the class `istream'
6.5.1.1: Reading from `istream' objects
6.5.1.2: `istream' positioning
6.5.2: Input from files: the class `ifstream'
6.5.3: Input from memory: the class `istringstream'
6.5.4: Copying streams
6.5.5: Coupling streams

6.6: Advanced topics

6.6.1: Redirecting streams
6.6.2: Reading AND Writing streams

Chapter 7: Classes

7.1: The constructor

7.1.1: A first application
7.1.2: Constructors: with and without arguments
7.1.2.1: The order of construction

7.2: Ambiguity resolution

7.2.1: Types `Data' vs. `Data()'
7.2.2: Superfluous parentheses
7.2.3: Existing types

7.3: Objects inside objects: composition

7.3.1: Composition and const objects: const member initializers
7.3.2: Composition and reference objects: reference member initializers

7.4: Data member initializers

7.4.1: Delegating constructors

7.5: Uniform initialization

7.6: Defaulted and deleted class members

7.7: Const member functions and const objects

7.7.1: Anonymous objects
7.7.1.1: Subtleties with anonymous objects

7.8: Member function reference bindings (& and &&)

7.9: The keyword `inline'

7.9.1: Defining members inline
7.9.2: When to use inline functions
7.9.2.1: A prelude: when NOT to use inline functions

7.10: Local classes: classes inside functions

7.11: The keyword `mutable'

7.12: Header file organization

7.12.1: Using namespaces in header files

7.13: Sizeof applied to class data members

Chapter 8: Static Data And Functions

8.1: Static data

8.1.1: Private static data
8.1.2: Public static data
8.1.3: Initializing static const data
8.1.4: Generalized constant expressions (constexpr)
8.1.4.1: Constant expression data

8.2: Static member functions

8.2.1: Calling conventions

Chapter 9: Classes And Memory Allocation

9.1: Operators `new' and `delete'

9.1.1: Allocating arrays
9.1.2: Deleting arrays
9.1.3: Enlarging arrays
9.1.4: Managing `raw' memory
9.1.5: The `placement new' operator

9.2: The destructor

9.2.1: Object pointers revisited
9.2.2: The function set_new_handler()

9.3: The assignment operator

9.3.1: Overloading the assignment operator
9.3.1.1: The member 'operator=()'

9.4: The `this' pointer

9.4.1: Sequential assignments and this

9.5: The copy constructor: initialization vs. assignment

9.6: Revising the assignment operator

9.6.1: Swapping
9.6.1.1: Fast swapping

9.7: Moving data

9.7.1: The move constructor (dynamic data)
9.7.2: The move constructor (composition)
9.7.3: Move-assignment
9.7.4: Revising the assignment operator (part II)
9.7.5: Moving and the destructor
9.7.6: Move-only classes
9.7.7: Default move constructors and assignment operators
9.7.8: Moving: implications for class design

9.8: Copy Elision and Return Value Optimization

9.9: Plain Old Data

9.10: Conclusion

Chapter 10: Exceptions

10.1: Exception syntax

10.2: An example using exceptions

10.2.1: Anachronisms: `setjmp' and `longjmp'
10.2.2: Exceptions: the preferred alternative

10.3: Throwing exceptions

10.3.1: The empty `throw' statement

10.4: The try block

10.5: Catching exceptions

10.5.1: The default catcher

10.6: Declaring exception throwers (deprecated)

10.7: Iostreams and exceptions

10.8: Standard Exceptions

10.9: System error, error code and error category

10.9.1: The class `std::error_code'
10.9.2: The class `std::error_category'

10.10: Exception guarantees

10.10.1: The basic guarantee
10.10.2: The strong guarantee
10.10.3: The nothrow guarantee

10.11: Function try blocks

10.12: Exceptions in constructors and destructors

Chapter 11: More Operator Overloading

11.1: Overloading `operator[]()'

11.2: Overloading the insertion and extraction operators

11.3: Conversion operators

11.4: The keyword `explicit'

11.4.1: Explicit conversion operators

11.5: Overloading the increment and decrement operators

11.6: Overloading binary operators

11.7: Overloading `operator new(size_t)'

11.8: Overloading `operator delete(void *)'

11.9: Operators `new[]' and `delete[]'

11.9.1: Overloading `new[]'
11.9.2: Overloading `delete[]'
11.9.3: `new[]', `delete[]' and exceptions

11.10: Function Objects

11.10.1: Constructing manipulators
11.10.1.1: Manipulators requiring arguments

11.11: The case of [io]fstream::open()

11.12: User-defined literals

11.13: Overloadable operators

Chapter 12: Abstract Containers

12.1: Notations used in this chapter

12.2: The `pair' container

12.3: Allocators

12.4: Available Containers

12.4.1: ARRAY
12.4.2: The `vector' container
12.4.3: The `list' container
12.4.4: The `queue' container
12.4.5: The `priority_queue' container
12.4.6: The `deque' container
12.4.7: The `map' container
12.4.7.1: The `map' constructors
12.4.7.2: The `map' operators
12.4.7.3: The `map' public members
12.4.7.4: The `map': a simple example
12.4.8: The `multimap' container
12.4.9: The `set' container
12.4.10: The `multiset' container
12.4.11: The `stack' container
12.4.12: The `unordered_map' container (`hash table')
12.4.12.1: The `unordered_map' constructors
12.4.12.2: The `unordered_map' public members
12.4.12.3: The `unordered_multimap' container
12.4.13: The `unordered_set' container
12.4.13.1: The `unordered_multiset' container

12.5: Regular Expressions

12.6: The `complex' container

12.7: Unrestricted Unions

12.7.1: Implementing the destructor
12.7.2: Embedding an unrestricted union in a surrounding class
12.7.3: Destroying an embedded unrestricted union
12.7.4: Copy and move constructors
12.7.5: Assignment

Chapter 13: Inheritance

13.1: Related types

13.1.1: Inheritance depth: desirable?

13.2: Access rights: public, private, protected

13.2.1: Public, protected and private derivation
13.2.2: Promoting access rights

13.3: The constructor of a derived class

13.3.1: Move construction
13.3.2: Move assignment
13.3.3: Inheriting constructors

13.4: The destructor of a derived class

13.5: Redefining member functions

13.6: i/ostream::init

13.7: Multiple inheritance

13.8: Conversions between base classes and derived classes

13.8.1: Conversions with object assignments
13.8.2: Conversions with pointer assignments

13.9: Using non-default constructors with new[]

Chapter 14: Polymorphism

14.1: Virtual functions

14.2: Virtual destructors

14.3: Pure virtual functions

14.3.1: Implementing pure virtual functions

14.4: Explicit virtual overrides

14.5: Virtual functions and multiple inheritance

14.5.1: Ambiguity in multiple inheritance
14.5.2: Virtual base classes
14.5.3: When virtual derivation is not appropriate

14.6: Run-time type identification

14.6.1: The dynamic_cast operator
14.6.2: The `typeid' operator

14.7: Inheritance: when to use to achieve what?

14.8: The `streambuf' class

14.8.1: Protected `streambuf' members
14.8.1.1: Protected members for input operations
14.8.1.2: Protected members for output operations
14.8.1.3: Protected members for buffer manipulation
14.8.1.4: Deriving classes from `streambuf'
14.8.2: The class `filebuf'

14.9: A polymorphic exception class

14.10: How polymorphism is implemented

14.11: Undefined reference to vtable ...

14.12: Virtual constructors

Chapter 15: Friends

15.1: Friend functions

15.2: Extended friend declarations

Chapter 16: Classes Having Pointers To Members

16.1: Pointers to members: an example

16.2: Defining pointers to members

16.3: Using pointers to members

16.4: Pointers to static members

16.5: Pointer sizes

Chapter 17: Nested Classes

17.1: Defining nested class members

17.2: Declaring nested classes

17.3: Accessing private members in nested classes

17.4: Nesting enumerations

17.4.1: Empty enumerations

17.5: Revisiting virtual constructors

Chapter 18: The Standard Template Library

18.1: Predefined function objects

18.1.1: Arithmetic function objects
18.1.2: Relational function objects
18.1.3: Logical function objects
18.1.4: Function adaptors
18.1.4.1: Binders
18.1.4.2: Negators

18.2: Iterators

18.2.1: std::distance
18.2.2: Insert iterators
18.2.3: Iterators for `istream' objects
18.2.3.1: Iterators for `istreambuf' objects
18.2.4: Iterators for `ostream' objects
18.2.4.1: Iterators for `ostreambuf' objects

18.3: The class 'unique_ptr'

18.3.1: Defining `unique_ptr' objects
18.3.2: Creating a plain `unique_ptr'
18.3.3: Moving another `unique_ptr'
18.3.4: Pointing to a newly allocated object
18.3.5: Operators and members
18.3.6: Using `unique_ptr' objects for arrays
18.3.7: The legacy class 'auto_ptr' (deprecated)

18.4: The class 'shared_ptr'

18.4.1: Defining `shared_ptr' objects
18.4.2: Creating a plain `shared_ptr'
18.4.3: Pointing to a newly allocated object
18.4.4: Operators and members
18.4.5: Casting shared pointers
18.4.6: Using `shared_ptr' objects for arrays

18.5: Using `make_shared' to combine `shared_ptr' and `new'

18.6: Classes having pointer data members

18.7: Lambda expressions

18.8: Randomization and Statistical Distributions

18.8.1: Random Number Generators
18.8.2: Statistical distributions
18.8.2.1: Bernoulli distribution
18.8.2.2: Binomial distribution
18.8.2.3: Cauchy distribution
18.8.2.4: Chi-squared distribution
18.8.2.5: Extreme value distribution
18.8.2.6: Exponential distribution
18.8.2.7: Fisher F distribution
18.8.2.8: Gamma distribution
18.8.2.9: Geometric distribution
18.8.2.10: Log-normal distribution
18.8.2.11: Normal distribution
18.8.2.12: Negative binomial distribution
18.8.2.13: Poisson distribution
18.8.2.14: Student t distribution
18.8.2.15: Uniform int distribution
18.8.2.16: Uniform real distribution
18.8.2.17: Weibull distribution

Chapter 19: The STL Generic Algorithms

19.1: The Generic Algorithms

19.1.1: accumulate
19.1.2: adjacent_difference
19.1.3: adjacent_find
19.1.4: binary_search
19.1.5: copy
19.1.6: copy_backward
19.1.7: count
19.1.8: count_if
19.1.9: equal
19.1.10: equal_range
19.1.11: fill
19.1.12: fill_n
19.1.13: find
19.1.14: find_end
19.1.15: find_first_of
19.1.16: find_if
19.1.17: for_each
19.1.18: generate
19.1.19: generate_n
19.1.20: includes
19.1.21: inner_product
19.1.22: inplace_merge
19.1.23: iter_swap
19.1.24: lexicographical_compare
19.1.25: lower_bound
19.1.26: max
19.1.27: max_element
19.1.28: merge
19.1.29: min
19.1.30: min_element
19.1.31: mismatch
19.1.32: next_permutation
19.1.33: nth_element
19.1.34: partial_sort
19.1.35: partial_sort_copy
19.1.36: partial_sum
19.1.37: partition
19.1.38: prev_permutation
19.1.39: random_shuffle
19.1.40: remove
19.1.41: remove_copy
19.1.42: remove_copy_if
19.1.43: remove_if
19.1.44: replace
19.1.45: replace_copy
19.1.46: replace_copy_if
19.1.47: replace_if
19.1.48: reverse
19.1.49: reverse_copy
19.1.50: rotate
19.1.51: rotate_copy
19.1.52: search
19.1.53: search_n
19.1.54: set_difference
19.1.55: set_intersection
19.1.56: set_symmetric_difference
19.1.57: set_union
19.1.58: sort
19.1.59: stable_partition
19.1.60: stable_sort
19.1.61: swap
19.1.62: swap_ranges
19.1.63: transform
19.1.64: unique
19.1.65: unique_copy
19.1.66: upper_bound
19.1.67: Heap algorithms
19.1.67.1: The `make_heap' function
19.1.67.2: The `pop_heap' function
19.1.67.3: The `push_heap' function
19.1.67.4: The `sort_heap' function
19.1.67.5: An example using the heap functions

19.2: STL: More function adaptors

19.2.1: Member function adaptors
19.2.2: Adaptable functions

Chapter 20: Multi Threading

20.1: Handling time (absolute and relative)

20.1.1: Units: the class 'ratio'
20.1.2: Amounts of time: the class 'duration'
20.1.3: Clocks measuring time
20.1.4: Points in time: the class 'time_point'
20.1.5: Converting time to a NTBS

20.2: Multi Threading

20.2.1: The namespace `std::this_thread'
20.2.2: The class `std::thread'
20.2.2.1: Static data and threads: thread_local
20.2.2.2: Exceptions and join()

20.3: Synchronization (mutexes)

20.3.1: Initialization in multi-threaded programs

20.4: Locks and lock handling

20.4.1: Deadlocks

20.5: Event handling (condition variables)

20.5.1: The class 'std::condition_variable'
20.5.2: The class 'std::condition_variable_any'
20.5.3: An example using condition variables

20.6: Atomic actions: mutexes not required

20.7: An example: threaded quicksort

20.8: Shared States

20.9: Asynchronous return objects: the class `std::future'

20.9.1: The std::future_error exception and the std::future_errc enum

20.10: Shared asynchronous return objects: the class `std::shared_future'

20.11: Starting a new thread: the function `std::async'

20.12: Preparing a task for execution: the class `std::packaged_task'

20.13: The class `std::promise'

20.13.1: Exception propagation: the class `std::exception_ptr'

20.14: An example: multi-threaded compilations

Chapter 21: Function Templates

21.1: Defining function templates

21.1.1: Considerations regarding template parameters
21.1.2: Late-specified return type

21.2: Passing arguments by reference (reference wrappers)

21.3: Using Local and unnamed types as template arguments

21.4: Template parameter deduction

21.4.1: Lvalue transformations
21.4.2: Qualification transformations
21.4.3: Transformation to a base class
21.4.4: The template parameter deduction algorithm
21.4.5: Template type contractions

21.5: Declaring function templates

21.5.1: Instantiation declarations

21.6: Instantiating function templates

21.6.1: Instantiations: no `code bloat'

21.7: Using explicit template types

21.8: Overloading function templates

21.8.1: An example using overloaded function templates
21.8.2: Ambiguities when overloading function templates
21.8.3: Declaring overloaded function templates

21.9: Specializing templates for deviating types

21.9.1: Avoiding too many specializations
21.9.2: Declaring specializations
21.9.3: Complications when using the insertion operator

21.10: Static assertions

21.11: Numeric limits

21.12: Polymorphous wrappers for function objects

21.13: Compiling template definitions and instantiations

21.14: The function selection mechanism

21.15: Determining the template type parameters

21.16: SFINAE: Substitution Failure Is Not An Error

21.17: Summary of the template declaration syntax

Chapter 22: Class Templates

22.1: Defining class templates

22.1.1: Constructing the circular queue: CirQue
22.1.2: Non-type parameters
22.1.3: Member templates
22.1.4: CirQue's constructors and member functions
22.1.5: Using CirQue objects
22.1.6: Default class template parameters
22.1.7: Declaring class templates
22.1.8: Preventing template instantiations

22.2: Static data members

22.2.1: Extended use of the keyword `typename'

22.3: Specializing class templates for deviating types

22.3.1: Example of a class specialization

22.4: Partial specializations

22.4.1: Intermezzo: some simple matrix algebraic concepts
22.4.2: The Matrix class template
22.4.3: The MatrixRow partial specialization
22.4.4: The MatrixColumn partial specialization
22.4.5: The 1x1 matrix: avoid ambiguity

22.5: Variadic templates

22.5.1: Defining and using variadic templates
22.5.2: Perfect forwarding
22.5.2.1: References to references
22.5.3: The unpack operator
22.5.4: Non-type variadic templates

22.6: Tuples

22.7: Computing the return type of function objects

22.8: Instantiating class templates

22.9: Processing class templates and instantiations

22.10: Declaring friends

22.10.1: Non-templates used as friends in templates
22.10.2: Templates instantiated for specific types as friends
22.10.3: Unbound templates as friends
22.10.4: Extended friend declarations

22.11: Class template derivation

22.11.1: Deriving ordinary classes from class templates
22.11.2: Deriving class templates from class templates
22.11.3: Deriving class templates from ordinary classes

22.12: Static Polymorphism

22.12.1: An example of static polymorphism
22.12.2: Converting dynamic polymorphic classes to static polymorphic classes
22.12.3: Using static polymorphism to avoid reimplementations

22.13: Class templates and nesting

22.14: Constructing iterators

22.14.1: Implementing a `RandomAccessIterator'
22.14.2: Implementing a `reverse_iterator'

Chapter 23: Advanced Template Use

23.1: Subtleties

23.1.1: Returning types nested under class templates
23.1.2: Type resolution for base class members
23.1.3: ::template, .template and ->template

23.2: Template Meta Programming

23.2.1: Values according to templates
23.2.1.1: Converting integral types to types
23.2.2: Selecting alternatives using templates
23.2.2.1: Defining overloading members
23.2.2.2: Class structure as a function of template parameters
23.2.2.3: An illustrative example
23.2.3: Templates: Iterations by Recursion

23.3: User-defined literals

23.4: Template template parameters

23.4.1: Policy classes - I
23.4.2: Policy classes - II: template template parameters
23.4.2.1: The destructor of Policy classes
23.4.3: Structure by Policy

23.5: Template aliases

23.6: Trait classes

23.6.1: Distinguishing class from non-class types
23.6.2: Available type traits

23.7: Using `noexcept' when offering the `strong guarantee'

23.8: More conversions to class types

23.8.1: Types to types
23.8.2: An empty type
23.8.3: Type convertibility
23.8.3.1: Determining inheritance

23.9: Template TypeList processing

23.9.1: The length of a TypeList
23.9.2: Searching a TypeList
23.9.3: Selecting from a TypeList
23.9.4: Prefixing/Appending to a TypeList
23.9.5: Erasing from a TypeList
23.9.5.1: Erasing the first occurrence
23.9.5.2: Erasing a type by its index
23.9.5.3: Erasing all occurrences of a type
23.9.5.4: Erasing duplicates

23.10: Using a TypeList

23.10.1: The Wrap and Multi class templates
23.10.2: The MultiBase class template
23.10.3: Support templates
23.10.4: Using Multi

Chapter 24: Concrete Examples

24.1: Using file descriptors with `streambuf' classes

24.1.1: Classes for output operations
24.1.2: Classes for input operations
24.1.2.1: Using a one-character buffer
24.1.2.2: Using an n-character buffer
24.1.2.3: Seeking positions in `streambuf' objects
24.1.2.4: Multiple `unget' calls in `streambuf' objects
24.1.3: Fixed-sized field extraction from istream objects
24.1.3.1: Member functions and example

24.2: The `fork' system call

24.2.1: A basic Fork class
24.2.2: Parents and Children
24.2.3: Redirection revisited
24.2.4: The `Daemon' program
24.2.5: The class `Pipe'
24.2.6: The class `ParentSlurp'
24.2.7: Communicating with multiple children
24.2.7.1: The class `Selector': interface
24.2.7.2: The class `Selector': implementation
24.2.7.3: The class `Monitor': interface
24.2.7.4: The class `Monitor': s_handler
24.2.7.5: The class `Monitor': the member `run'
24.2.7.6: The class `Monitor': example
24.2.7.7: The class `Child'

24.3: Function objects performing bitwise operations

24.4: Adding binary operators to classes

24.4.1: Binary operators allowing promotions

24.5: Range-based for-loops and pointer-ranges

24.6: Distinguishing lvalues from rvalues with operator[]()

24.7: Implementing a `reverse_iterator'

24.8: Using `bisonc++' and `flexc++'

24.8.1: Using `flexc++' to create a scanner
24.8.1.1: The derived class `Scanner'
24.8.1.2: The lexical scanner specification file
24.8.1.3: Implementing `Scanner'
24.8.1.4: Using a `Scanner' object
24.8.1.5: Building the program
24.8.2: Using `bisonc++' and `flexc++'
24.8.2.1: The `bisonc++' specification file
24.8.2.2: The `flexc++' specification file
24.8.2.3: Building the program
24.8.3: Bisonc++: using polymorphic semantic values
24.8.3.1: The parser using a polymorphic semantic value type
24.8.3.2: Tagging the actual semantic type: the `enum class Tag'
24.8.3.3: (Im)mutable semantic data: two base-structs
24.8.3.4: Traits of semantic type tags: the `TagTrait' trait class
24.8.3.5: Accessing data from derived classes
24.8.3.6: The polymorphic base class `SemBase'
24.8.3.7: The class template `Semantic', derived from `SemBase'
24.8.3.8: Adding new semantic data types
24.8.3.9: The parser's semantic value: `spSemBase'
24.8.3.10: The parser specification file
24.8.3.11: The scanner using a polymorphic semantic value type