stdxFunctional.h Classes and Functions

A collection of simple function objects to help make stl eaiser to use. Many of these are nicer ways to create comparison predicates for use with various _if STL algorithms. You can achieve the same effect with std::bind2nd but it's ugly and harder to read. So below are two ways to do the same thing:

 copy_if( iseq(lst1), back_inserter(lst2), bind2nd( less<int>(), 7 );
 copy_if( iseq(lst1), back_inserter(lst2), less_than(7) );

In combination with the stdx::filter() functions this can be pretty powerful and elegant. For example if we have a collection of Person objects and we want to create a view of that list which only contains people whose occupation is Student then we could use the following:

 list<Person> lst;
 // ... fill lst with people ...
 list<Person> students;
 copy_if( iseq(lst), back_inserter(students), 
          filter( &Person::getOccupation, equal(Student) ) );

Compounds

class stdx::Equal
Function Object: Equal to predicate object.
class stdx::NotEqual
Function Object: Not equal to predicate object.
class stdx::LessThan
Function Object: Less than predicate object.
class stdx::GreaterThan
Function Object: Greater than predicate object.
class stdx::LessThanOrEqual
Function Object: Less than or equal to predicate object.
class stdx::GreaterThanOrEqual
Function Object: Greater than or equal predicate object.

Functions

Comparison Predicate Helper Functions

equal (const T &val)
not_equal (const T &val)
less_than (const T &val)
greater_than (const T &val)
less_than_or_equal (const T &val)
greater_than_or_equal (const T &val)

Detailed Documentation

Function Documentation

template<class T>
Equal<T> equal	(	const T &	val	)

template<class T>
NotEqual<T> not_equal	(	const T &	val	)

template<class T>
LessThan<T> less_than	(	const T &	val	)

template<class T>
GreaterThan<T> greater_than	(	const T &	val	)

template<class T>
LessThanOrEqual<T> less_than_or_equal	(	const T &	val	)

template<class T>
GreaterThanOrEqual<T> greater_than_or_equal	(	const T &	val	)

C++ Extensions (cppx) Documentation	Internal Version
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