Qore::AbstractIterator Class Reference

This class defines an abstract interface for iterators. More...

#include <QC_AbstractIterator.dox.h>

Inheritance diagram for Qore::AbstractIterator:

Public Member Methods
abstract auto	getValue ()
	returns the current value
abstract bool	next ()
	Moves the current position to the next element; returns False if there are no more elements.
abstract bool	valid ()
	returns True if the iterator is currently pointing at a valid element, False if not

Detailed Description

This class defines an abstract interface for iterators.

Classes inheriting this class can be used to iterate abstract or complex objects with while Statements (using AbstractIterator::next()) or directly in the following language constructs:

• Map Operator (map)
• Fold Right Operator (foldr) and Fold Left Operator (foldl)
• Select From List Operator (select)
• foreach Statements

Member Function Documentation

getValue()

abstract auto Qore::AbstractIterator::getValue

(

)

returns the current value

Returns

the current value

Example:

while (i.next()) {
    printf("+ %y\n", i.getValue());
}

Exceptions

INVALID-ITERATOR

the iterator is not pointing at a valid element

See also

AbstractIterator::valid()

next()

abstract bool Qore::AbstractIterator::next

(

)

Moves the current position to the next element; returns False if there are no more elements.

This method will return True again after it returns False once if the object being iterated is not empty, otherwise it will always return False. The iterator object should not be used after this method returns False

Returns

False if there are no more elements (in which case the iterator object is invalid and should not be used); True if successful (meaning that the iterator object is valid)

Example:

while (i.next()) {
    printf(" + %y\n", i.getValue());
}

valid()

abstract bool Qore::AbstractIterator::valid

(

)

returns True if the iterator is currently pointing at a valid element, False if not

Returns

True if the iterator is currently pointing at a valid element, False if not

Example:

if (i.valid())
    printf("current value: %y\n", i.getValue());