using std:;swap();

C.165 added.
Also: glossary extended.

Please review both.

CppCoreGuidelines.md

@@ -1,6 +1,6 @@
 # <a name="main"></a> C++ Core Guidelines
 
-October 9, 2015
+October 10, 2015
 
 Editors:
 
@@ -5821,6 +5821,7 @@ Overload rule summary:
 * [C.162: Overload operations that are roughly equivalent](#Ro-equivalent)
 * [C.163: Overload only for operations that are roughly equivalent](#Ro-equivalent-2)
 * [C.164: Avoid conversion operators](#Ro-conversion)
+* [C.165: Use `using` for customization points](#Ro-custom)
 * [C.170: If you feel like overloading a lambda, use a generic lambda](#Ro-lambda)
 
 ### <a name="Ro-conventional"></a> C.160: Define operators primarily to mimic conventional usage
@@ -5948,6 +5949,56 @@ The string allocated for `s` and assigned to `p` is destroyed before it can be u
 
 Flag all conversion operators.
 
+
+
+### <a name="Ro-custom"></a> C.165: Use `using` for customization points
+
+##### Reason
+
+To find function objects and functions defined in a separate namespace to "customize" a common function.
+
+##### Example
+
+Consider `swap`. It is a general (standard library) function with a definintion that will work for just about any type.
+However, it is desirable to define specific `swap()`s for specific types.
+For example, the general `swap()` will copy the elements of two `vector`s being swapped, whereas a good specific implementation will not copy elements at all.
+
+	namespace N {
+		My_type X { /* ... */ };
+		void swap(X&,X&);	// optimized swap for N::X
+		// ...
+	}
+	
+	void f1(N::X& a, N::X& b)
+	{
+		std::swap(a,b);		// propably not what we we wanted: calls std::swap()
+	}
+
+The `std::swap()` in `f1()` does exactly what we asked it to do: it calls the `swap()` in namespace `std`.
+Unfortunately, that's probably not what we wanted.
+How do we get `N::X` considered?
+
+	void f2(N::X& a, N::X& b)
+	{
+		swap(a,b);		// calls N::swap
+	}
+	 
+But that may not be what we wanted for generic code.
+There, we typically want the specific function if it exists and the general function if not.
+This is done by including the general function in the lookup for the function:
+
+	void f3(N::X& a, N::X& b)
+	{
+		using std::swap;	// make std::swap available
+		swap(a,b);			// calls N::swap if it exists, otherwise std::swap
+	}
+	
+
+##### Enforcement
+
+Unlikely, except for known customization points, such as `swap`.
+The problem is that the unqualified and qualified lookups both have uses.
+
 ### <a name="Ro-lambda"></a> C.170: If you feel like overloading a lambda, use a generic lambda
 
 ##### Reason
@@ -13680,6 +13731,7 @@ When is a class a container? ???
 # <a name="S-glossary"></a> Glossary
 
 A relatively informal definition of twrms used in the guidelines
+(based of the glossary in [Programming: Principles and Practice using C++](http://www.stroustrup.com/programming.html))
 
 * *abstract*: class a class that cannot be directly used to create objects; often used to define an interface to derived classes.
 A class is made abstract by having a pure virtual function or a protected constructor.
@@ -13705,11 +13757,115 @@ Sometimes complexity is used to (simply) mean an estimate of the number of opera
 * *computation*: the execution of some code, usually taking some input and producing some output.
 * *concept*: (1) a notion, and idea; (2) a set of requirements, usually for a template argument
 * *concrete class*: class for which objects can be created.
-* ???
+* *constant*: a value that cannot be changed (in a given scope); not mutable.
+* *constructor*: an operation that initializes (“constructs”) an object.
+Typically a constructor establishes an invariant and often acquires resources needed for an object to be used (which are then typically released by a destructor).
+* *container*: an object that holds elements (other objects).
+* *copy*: an operation that makes two object have values that compare equal. See also move.
+* *correctness*: a program or a piece of a program is correct if it meets its specification.
+Unfortunately, a specification can be incomplete or inconsistent, or can fail to meet users’ reasonable expectations.
+Thus, to produce acceptable code, we sometimes have to do more than just follow the formal specification.
+* *cost*: the expense (e.g., in programmer time, run time, or space) of producing a program or of executing it.
+Ideally, cost should be a function of complexity.
+* *customisation point*: ???
+* *data*: values used in a computation.
+* *debugging*: the act of searching for and removing errors from a program; usually far less systematic than testing.
+* *declaration*: the specification of a name with its type in a program.
+* *definition*: a declaration of an entity that supplies all information necessary to complete a program using the entity.
+Simplified definition: a declaration that allocates memory.
+* *derived class*: a class derived from one or more base classes.
+* *design*: an overall description of how a piece of software should operate to meet its specification.
+* *destructor*: an operation that is implicitly invoked (called) when an object is destroyed (e.g., at the end of a scope). Often, it releases resources.
+* *encapsulation*: protecting something meant to be private (e.g., implementation details) from unauthorized access.
+* *error*: a mismatch between reasonable expectations of program behavior (often expressed as a requirement or a users’ guide) and what a program actually does.
+* *executable*: a program ready to be run (executed) on a computer.
+* *feature creep*: a tendency to add excess functionality to a program “just in case.”
+* *file*: a container of permanent information in a computer.
+* *floating-point number*: a computer’s approximation of a real number, such as 7.93 and 10.78e–3.
+* *function*: a named unit of code that can be invoked (called) from different parts of a program; a logical unit of computation.
+* *generic programming*: a style of programming focused on the design and efficient implementation of algorithms.
+A generic algorithm will work for all argument types that meet its requirements. In C++, generic programming typically uses templates.
 * *Global variable*: Technically, a named object in namespace scope
-* ???
+* *handle*: a class that allows access to another through a member pointer or reference. See also resource, copy, move.
+* *header*: a file containing declarations used to share interfaces between parts of a program.
+* *hiding*: the act of preventing a piece of information from being directly seen or accessed.
+For example, a name from a nested (inner) scope can prevent that same name from an outer (enclosing) scope from being directly used.
+* *ideal*: the perfect version of something we are striving for. Usually we have to make trade-offs and settle for an approximation. 
+* *implementation*: (1) the act of writing and testing code; (2) the code that implements a program.
+* *infinite loop*: a loop where the termination condition never becomes true. See iteration.
+* *infinite recursion*: a recursion that doesn’t end until the machine runs out of memory to hold the calls.
+In reality, such recursion is never infinite but is terminated by some hardware error. 
+* *information hiding*: the act of separating interface and implementation, thus hiding implementation details not meant for the user’s attention and providing an abstraction.
+* *initialize*: giving an object its first (initial) value.
+* *input*: values used by a computation (e.g., function arguments and characters typed on a keyboard).
+* *integer*: a whole number, such as 42 and –99.
+* *interface*: a declaration or a set of declarations specifying how a piece of code (such as a function or a class) can be called.
+* *invariant*: something that must be always true at a given point (or points) of a program; typically used to describe the state (set of values) of an object or the state of a loop before entry into the repeated statement.
+* *iteration*: the act of repeatedly executing a piece of code; see recursion. 
+* *iterator*: an object that identifies an element of a sequence.
+* *library*: a collection of types, functions, classes, etc. implementing a set of facilities (abstractions) meant to be potentially used as part of more that one program.
+* *lifetime*: the time from the initialization of an object until it becomes unusable (goes out of scope, is deleted, or the program terminates).
+* *linker*: a program that combines object code files and libraries into an executable program.
+* *literal*: a notation that directly specifies a value, such as 12 specifying the integer value “twelve.”
+* *loop*: a piece of code executed repeatedly; in C++, typically a for-statement or a while-statement.
+* *move*: an operation that transfers a value from one object to another leaving behind a value representing “empty.” See also copy.
+* *mutable*: changeable; the opposite of immutable, constant, and variable.
+* *object*: (1) an initialized region of memory of a known type which holds a value of that type; (2) a region of memory.
+* *object code*: output from a compiler intended as input for a linker (for the linker to produce executable code).
+* *object file*: a file containing object code.
+* *object-oriented programming*: (OOP) a style of programming focused on the design and use of classes and class hierarchies.
+* *operation*: something that can perform some action, such as a function and an operator.
+* *output*: values produced by a computation (e.g., a function result or lines of characters written on a screen).
+* *overflow*: producing a value that cannot be stored in its intended target. 
+* *overload*: defining two functions or operators with the same name but different argument (operand) types.
+* *override*: defining a function in a derived class with the same name and argument types as a virtual function in the base class, thus making the function callable through the interface defined by the base class.
+* *owner*: an object responsible for releasing a resource.
+* *paradigm*: a somewhat pretentious term for design or programming style; often used with the (erroneous) implication that there exists a paradigm that is superior to all others.
+* *parameter*: a declaration of an explicit input to a function or a template. When called, a function can access the arguments passed through the names of its parameters.
+* *pointer*: (1) a value used to identify a typed object in memory; (2) a variable holding such a value.
+* *post-condition*: a condition that must hold upon exit from a piece of code, such as a function or a loop.
+* *pre-condition*: a condition that must hold upon entry into a piece of code, such as a function or a loop.
+* *program*: code (possibly with associated data) that is sufficiently complete to be executed by a computer.
+* *programming*: the art of expressing solutions to problems as code.
+* *programming language*: a language for expressing programs.
+* *pseudo code*: a description of a computation written in an informal notation rather than a programming language.
+* *pure virtual function*: a virtual function that must be overridden in a derived class.
+* *RAII*: (“Resource Acquisition Is Initialization”) a basic technique for resource management based on scopes.
+* *range*: a sequence of values that can be described by a start point and an end point. For example, [0:5) means the values 0, 1, 2, 3, and 4.
+* *regular expression*: a notation for patterns in character strings.
+* *recursion*: the act of a function calling itself; see also iteration.
+* *reference*: (1) a value describing the location of a typed value in memory; (2) a variable holding such a value.
+* *requirement*: (1) a description of the desired behavior of a program or part of a program; (2) a description of the assumptions a function or template makes of its arguments.
+* *resource*: something that is acquired and must later be released, such as a file handle, a lock, or memory. See also handle, owner.
+* *rounding*: conversion of a value to the mathematically nearest value of a less precise type.
+* *RTTI*: Run-Time Type Information. ???
+* *scope*: the region of program text (source code) in which a name can be referred to.
+* *sequence*: elements that can be visited in a linear order.
+* *software*: a collection of pieces of code and associated data; often used interchangeably with program.
+* *source code*: code as produced by a programmer and (in principle) readable by other programmers.
+* *source file*: a file containing source code.
+* *specification*: a description of what a piece of code should do.
+* *standard*: an officially agreed upon definition of something, such as a programming language.
+* *state*: a set of values.
 * *STL*: The containers, iterators, and algorithms part of the standard library
-* ???
+* *string*: a sequence of characters.
+* *style*: a set of techniques for programming leading to a consistent use of language features; sometimes used in a very restricted sense to refer just to low-level rules for naming and appearance of code.
+* *subtype*: derived type; a type that has all the properties of a type and possibly more.
+* *supertype*: base type; a type that has a subset of the properties of a type.
+* *system*: (1) a program or a set of programs for performing a task on a computer; (2) a shorthand for “operating system,” that is, the fundamental execution environment and tools for a computer.
+* *template*: a class or a function parameterized by one or more types or (compile-time) values; the basic C++ language construct supporting generic programming.
+* *testing*: a systematic search for errors in a program.
+* *trade-off*: the result of balancing several design and implementation criteria.
+* *truncation*: loss of information in a conversion from a type into another that cannot exactly represent the value to be converted.
+* *type*: something that defines a set of possible values and a set of operations for an object.
+* *uninitialized*: the (undefined) state of an object before it is initialized.
+* *unit*: (1) a standard measure that gives meaning to a value (e.g., km for a distance); (2) a distinguished (e.g., named) part of a larger whole. 
+* *use case*: a specific (typically simple) use of a program meant to test its functionality and demonstrate its purpose.
+* *value*: a set of bits in memory interpreted according to a type.
+* *variable*: a named object of a given type; contains a value unless uninitialized.
+* *virtual function*: a member function that can be overridden in a derived class.
+* *word*: a basic unit of memory in a computer, often the unit used to hold an integer.
+