ruby--ruby/ext/enumerator/enumerator.txt

.\" enumerator.txt -  -*- Indented-Text -*-
$Idaemons: /home/cvs/rb/enumerator/enumerator.txt,v 1.2 2001/07/15 10:19:24 knu Exp $
$RoughId: enumerator.txt,v 1.5 2003/02/20 12:24:51 knu Exp $
$Id$

** Enumerable::Enumerator(Class)

A class which provides a method `each' to be used as an Enumerable
object.

Superclass: Object

Mix-ins: Enumerable

require 'enumerator'

Class Methods:

    new(obj, method = :each, *args)

	Creates a new Enumerable::Enumerator object, which is to be
	used as an Enumerable object using the given object's given
	method with the given arguments.

	e.g.:
	    str = "xyz"

	    enum = Enumerable::Enumerator.new(str, :each_byte)
	    a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]

Methods:

    each {...}

	Iterates the given block using the object and the method
	specified in the first place.


Requiring this module also adds some methods to the Object class:

    to_enum(method = :each, *args)
    enum_for(method = :each, *args)

	Returns Enumerable::Enumerator.new(self, method, *args).

	e.g.:
	    str = "xyz"

	    enum = str.enum_for(:each_byte)
	    a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]

	    # protects an array from being modified
	    a = [1, 2, 3]
	    some_method(a.to_enum)

And the Enumerable module.

    each_slice(n) {...}

	Iterates the given block for each slice of <n> elements.

	e.g.:
	    (1..10).each_slice(3) {|a| p a}
	    # outputs below
	    [1, 2, 3]
	    [4, 5, 6]
	    [7, 8, 9]
	    [10]

    enum_slice(n)

	Returns Enumerable::Enumerator.new(self, :each_slice, n).

    each_cons(n) {...}

	Iterates the given block for each array of consecutive <n>
	elements.

	e.g.:
	    (1..10).each_cons(3) {|a| p a}
	    # outputs below
	    [1, 2, 3]
	    [2, 3, 4]
	    [3, 4, 5]
	    [4, 5, 6]
	    [5, 6, 7]
	    [6, 7, 8]
	    [7, 8, 9]
	    [8, 9, 10]

    enum_cons(n)

	Returns Enumerable::Enumerator.new(self, :each_cons, n).

    enum_with_index

	Returns Enumerable::Enumerator.new(self, :each_with_index).

-------------------------------------------------------
Local variables:
fill-column: 70
end: