Similar to Object#to_enum
, except it returns a lazy enumerator. This makes it easy to define Enumerable
methods that will naturally remain lazy if called from a lazy enumerator.
For example, continuing from the example in Object#to_enum
:
# See Object#to_enum for the definition of repeat r = 1..Float::INFINITY r.repeat(2).first(5) # => [1, 1, 2, 2, 3] r.repeat(2).class # => Enumerator r.repeat(2).map{|n| n ** 2}.first(5) # => endless loop! # works naturally on lazy enumerator: r.lazy.repeat(2).class # => Enumerator::Lazy r.lazy.repeat(2).map{|n| n ** 2}.first(5) # => [1, 1, 4, 4, 9]
Like Enumerable#reject
, but chains operation to be lazy-evaluated.
Like Enumerable#grep
, but chains operation to be lazy-evaluated.
Like Enumerable#grep_v
, but chains operation to be lazy-evaluated.
Returns a Proc
object that takes arguments and yields them.
This method is implemented so that a Yielder
object can be directly passed to another method as a block argument.
enum = Enumerator.new { |y| Dir.glob("*.rb") { |file| File.open(file) { |f| f.each_line(&y) } } }
Return the length of the hash value in bytes.
Return the length of the hash value (the digest) in bytes.
Digest::SHA256.new.digest_length * 8 # => 256 Digest::SHA384.new.digest_length * 8 # => 384 Digest::SHA512.new.digest_length * 8 # => 512
For example, digests produced by Digest::SHA256
will always be 32 bytes (256 bits) in size.
Returns the output size of the digest, i.e. the length in bytes of the final message digest result.
digest = OpenSSL::Digest.new('SHA1') puts digest.digest_length # => 20
Called when the document starts with the declared version
, tag_directives
, if the document is implicit
.
version
will be an array of integers indicating the YAML
version being dealt with, tag_directives
is a list of tuples indicating the prefix and suffix of each tag, and implicit
is a boolean indicating whether the document is started implicitly.
Given the following YAML:
%YAML 1.1 %TAG ! tag:tenderlovemaking.com,2009: --- !squee
The parameters for start_document
must be this:
version # => [1, 1] tag_directives # => [["!", "tag:tenderlovemaking.com,2009:"]] implicit # => false
Called when a sequence is started.
anchor
is the anchor associated with the sequence or nil. tag
is the tag associated with the sequence or nil. implicit
a boolean indicating whether or not the sequence was implicitly started. style
is an integer indicating the list style.
See the constants in Psych::Nodes::Sequence
for the possible values of style
.
Here is a YAML
document that exercises most of the possible ways this method can be called:
--- - !!seq [ a ] - &pewpew - b
The above YAML
document consists of three lists, an outer list that contains two inner lists. Here is a matrix of the parameters sent to represent these lists:
# anchor tag implicit style [nil, nil, true, 1 ] [nil, "tag:yaml.org,2002:seq", false, 2 ] ["pewpew", nil, true, 1 ]
Called when a map starts.
anchor
is the anchor associated with the map or nil
. tag
is the tag associated with the map or nil
. implicit
is a boolean indicating whether or not the map was implicitly started. style
is an integer indicating the mapping style.
See the constants in Psych::Nodes::Mapping
for the possible values of style
.
Here is a YAML
document that exercises most of the possible ways this method can be called:
--- k: !!map { hello: world } v: &pewpew hello: world
The above YAML
document consists of three maps, an outer map that contains two inner maps. Below is a matrix of the parameters sent in order to represent these three maps:
# anchor tag implicit style [nil, nil, true, 1 ] [nil, "tag:yaml.org,2002:map", false, 2 ] ["pewpew", nil, true, 1 ]
Handles start_document
events with version
, tag_directives
, and implicit
styling.