YAML::BaseNode class
Constants used throughout the library
Handle Unicode-to-Internal conversion
Error messages and exception class
YAML::Loader class .. type handling ..
$Id: tag.rb 27365 2010-04-16 20:31:59Z tenderlove $
Author |
why the lucky stiff |
Classes required by the full core typeset
YAML(tm) (rhymes with ‘camel’) is a straightforward machine parsable data serialization format designed for human readability and interaction with scripting languages such as Perl and Python. YAML is optimized for data serialization, formatted dumping, configuration files, log files, Internet messaging and filtering. This specification describes the YAML information model and serialization format. Together with the Unicode standard for characters, it provides all the information necessary to understand YAML Version 1.0 and construct computer programs to process it.
See yaml.org/ for more information. For a quick tutorial, please visit YAML In Five Minutes (yaml.kwiki.org/?YamlInFiveMinutes).
The YAML 1.0 specification outlines four stages of YAML loading and dumping. This library honors all four of those stages, although data is really only available to you in three stages.
The four stages are: native, representation, serialization, and presentation.
The native stage refers to data which has been loaded completely into Ruby’s own types. (See +YAML::load+.)
The representation stage means data which has been composed into +YAML::BaseNode+ objects. In this stage, the document is available as a tree of node objects. You can perform YPath queries and transformations at this level. (See +YAML::parse+.)
The serialization stage happens inside the parser. The YAML parser used in Ruby is called Syck. Serialized nodes are available in the extension as SyckNode structs.
The presentation stage is the YAML document itself. This is accessible to you as a string. (See +YAML::dump+.)
For more information about the various information models, see Chapter 3 of the YAML 1.0 Specification (yaml.org/spec/#id2491269).
The YAML module provides quick access to the most common loading (YAML::load) and dumping (YAML::dump) tasks. This module also provides an API for registering global types (YAML::add_domain_type).
A simple round-trip (load and dump) of an object.
require "yaml" test_obj = ["dogs", "cats", "badgers"] yaml_obj = YAML::dump( test_obj ) # -> --- - dogs - cats - badgers ruby_obj = YAML::load( yaml_obj ) # => ["dogs", "cats", "badgers"] ruby_obj == test_obj # => true
To register your custom types with the global resolver, use add_domain_type.
YAML::add_domain_type( "your-site.com,2004", "widget" ) do |type, val| Widget.new( val ) end
Default settings
Error messages
Constants
Parser tokens
Add a transfer method for a builtin type
# File syck/lib/syck.rb, line 311
def self.add_builtin_type( type_tag, &transfer_proc )
resolver.add_type( "tag:yaml.org,2002:#{ type_tag }", transfer_proc )
end
Add a global handler for a YAML domain type.
# File syck/lib/syck.rb, line 304
def self.add_domain_type( domain, type_tag, &transfer_proc )
resolver.add_type( "tag:#{ domain }:#{ type_tag }", transfer_proc )
end
Add a private document type
# File syck/lib/syck.rb, line 326
def self.add_private_type( type_re, &transfer_proc )
warn "#{caller[0]}: YAML.add_private_type is deprecated, use add_domain_type" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
resolver.add_type( "x-private:" + type_re, transfer_proc )
end
Add a transfer method for a builtin type
# File syck/lib/syck.rb, line 318
def self.add_ruby_type( type_tag, &transfer_proc )
warn "#{caller[0]}: YAML.add_ruby_type is deprecated, use add_domain_type" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
resolver.add_type( "tag:ruby.yaml.org,2002:#{ type_tag }", transfer_proc )
end
Detect typing of a string
# File syck/lib/syck.rb, line 334
def self.detect_implicit( val )
warn "#{caller[0]}: YAML.detect_implicit is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
resolver.detect_implicit( val )
end
Converts obj to YAML and writes the YAML result to io.
File.open( 'animals.yaml', 'w' ) do |out| YAML.dump( ['badger', 'elephant', 'tiger'], out ) end
If no io is provided, a string containing the dumped YAML is returned.
YAML.dump( :locked ) #=> "--- :locked"
# File syck/lib/syck.rb, line 118
def self.dump( obj, io = nil )
obj.to_yaml( io || io2 = StringIO.new )
io || ( io2.rewind; io2.read )
end
Returns a YAML stream containing each of the items in objs, each having their own document.
YAML.dump_stream( 0, [], {} ) #=> --- 0 --- [] --- {}
# File syck/lib/syck.rb, line 293
def self.dump_stream( *objs )
d = Stream.new
objs.each do |doc|
d.add( doc )
end
d.emit
end
Calls block with each consecutive document in the YAML stream contained in io.
File.open( 'many-docs.yaml' ) do |yf| YAML.each_document( yf ) do |ydoc| ## ydoc contains the single object ## from the YAML document end end
# File syck/lib/syck.rb, line 218
def self.each_document( io, &block )
warn "#{caller[0]}: YAML.each_document is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
yp = parser.load_documents( io, &block )
end
Calls block with a tree of +YAML::BaseNodes+, one tree for each consecutive document in the YAML stream contained in io.
File.open( 'many-docs.yaml' ) do |yf| YAML.each_node( yf ) do |ydoc| ## ydoc contains a tree of nodes ## from the YAML document end end
# File syck/lib/syck.rb, line 249
def self.each_node( io, &doc_proc )
warn "#{caller[0]}: YAML.each_node is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
yp = generic_parser.load_documents( io, &doc_proc )
end
Returns a new default emitter
# File syck/lib/syck.rb, line 100
def self.emitter
warn "#{caller[0]}: YAML.emitter is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
Emitter.new.set_resolver( self.resolver )
end
Escape the string, condensing common escapes
# File syck/lib/syck/encoding.rb, line 10
def self.escape( value, skip = "" )
warn "#{caller[0]}: YAML.escape is deprecated" if $VERBOSE
value.gsub( /\\/, "\\\\\\" ).
gsub( /"/, "\\\"" ).
gsub( /([\x00-\x1f])/ ) do
skip[$&] || ESCAPES[ $&.unpack("C")[0] ]
end
end
Returns a new generic parser
# File syck/lib/syck.rb, line 88
def self.generic_parser
warn "#{caller[0]}: YAML.generic_parser is deprecated, switch to psych" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
Parser.new.set_resolver( GenericResolver )
end
Load a document from the current io stream.
File.open( 'animals.yaml' ) { |yf| YAML::load( yf ) } #=> ['badger', 'elephant', 'tiger']
Can also load from a string.
YAML.load( "--- :locked" ) #=> :locked
# File syck/lib/syck.rb, line 134
def self.load( io )
yp = parser.load( io )
end
Calls block with each consecutive document in the YAML stream contained in io.
File.open( 'many-docs.yaml' ) do |yf| YAML.load_documents( yf ) do |ydoc| ## ydoc contains the single object ## from the YAML document end end
# File syck/lib/syck.rb, line 234
def self.load_documents( io, &doc_proc )
yp = parser.load_documents( io, &doc_proc )
end
Load a document from the file located at filepath.
YAML.load_file( 'animals.yaml' ) #=> ['badger', 'elephant', 'tiger']
# File syck/lib/syck.rb, line 144
def self.load_file( filepath )
File.open( filepath ) do |f|
load( f )
end
end
Loads all documents from the current io stream, returning a +YAML::Stream+ object containing all loaded documents.
# File syck/lib/syck.rb, line 275
def self.load_stream( io )
d = nil
parser.load_documents( io ) do |doc|
d = Stream.new if not d
d.add( doc )
end
return d
end
Class method for creating streams
# File syck/lib/syck/stringio.rb, line 57
def Syck.make_stream( io )
if String === io
io = StringIO.new( io )
elsif not IO === io
raise Syck::Error, "YAML stream must be an IO or String object."
end
if Syck::unicode
def io.readline
Syck.utf_to_internal( readline( @ln_sep ), @utf_encoding )
end
def io.check_unicode
@utf_encoding = Syck.sniff_encoding( read( 4 ) )
@ln_sep = Syck.enc_separator( @utf_encoding )
seek( -4, IO::SEEK_CUR )
end
def io.utf_encoding
@utf_encoding
end
io.check_unicode
else
def io.utf_encoding
:None
end
end
io
end
Allocate blank object
# File syck/lib/syck.rb, line 377
def self.object_maker( obj_class, val )
warn "#{caller[0]}: YAML.object_maker is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
if Hash === val
o = obj_class.allocate
val.each_pair { |k,v|
o.instance_variable_set("@#{k}", v)
}
o
else
raise Error, "Invalid object explicitly tagged !ruby/Object: " + val.inspect
end
end
Parse the first document from the current io stream
File.open( 'animals.yaml' ) { |yf| YAML::load( yf ) } #=> #<YAML::Syck::Node:0x82ccce0 @kind=:seq, @value= [#<YAML::Syck::Node:0x82ccd94 @kind=:scalar, @type_id="str", @value="badger">, #<YAML::Syck::Node:0x82ccd58 @kind=:scalar, @type_id="str", @value="elephant">, #<YAML::Syck::Node:0x82ccd1c @kind=:scalar, @type_id="str", @value="tiger">]>
Can also load from a string.
YAML.parse( "--- :locked" ) #=> #<YAML::Syck::Node:0x82edddc @type_id="tag:ruby.yaml.org,2002:sym", @value=":locked", @kind=:scalar>
# File syck/lib/syck.rb, line 177
def self.parse( io )
yp = generic_parser.load( io )
end
Calls block with a tree of +YAML::BaseNodes+, one tree for each consecutive document in the YAML stream contained in io.
File.open( 'many-docs.yaml' ) do |yf| YAML.parse_documents( yf ) do |ydoc| ## ydoc contains a tree of nodes ## from the YAML document end end
# File syck/lib/syck.rb, line 265
def self.parse_documents( io, &doc_proc )
warn "#{caller[0]}: YAML.parse_documents is deprecated, use load_stream" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
self.each_node( io, &doc_proc )
end
Parse a document from the file located at filepath.
YAML.parse_file( 'animals.yaml' ) #=> #<YAML::Syck::Node:0x82ccce0 @kind=:seq, @value= [#<YAML::Syck::Node:0x82ccd94 @kind=:scalar, @type_id="str", @value="badger">, #<YAML::Syck::Node:0x82ccd58 @kind=:scalar, @type_id="str", @value="elephant">, #<YAML::Syck::Node:0x82ccd1c @kind=:scalar, @type_id="str", @value="tiger">]>
# File syck/lib/syck.rb, line 201
def self.parse_file( filepath )
File.open( filepath ) do |f|
parse( f )
end
end
Returns a new default parser
# File syck/lib/syck.rb, line 85
def self.parser; Parser.new.set_resolver( self.resolver ); end
Allocate an Emitter if needed
# File syck/lib/syck.rb, line 393
def self.quick_emit( oid, opts = {}, &e )
warn "#{caller[0]}: YAML.quick_emit is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
out =
if opts.is_a? Emitter
opts
else
emitter.reset( opts )
end
out.emit( oid, &e )
end
Method to extract colon-seperated type and class, returning the type and the constant of the class
# File syck/lib/syck.rb, line 367
def self.read_type_class( type, obj_class )
warn "#{caller[0]}: YAML.read_type_class is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
scheme, domain, type, tclass = type.split( ':', 4 )
tclass.split( "::" ).each { |c| obj_class = obj_class.const_get( c ) } if tclass
return [ type, obj_class ]
end
Returns the default resolver
# File syck/lib/syck.rb, line 94
def self.resolver
warn "#{caller[0]}: YAML.resolver is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
DefaultResolver
end
Associates a taguri tag with a Ruby class cls. The taguri is used to give types to classes when loading YAML. Taguris are of the form:
tag:authorityName,date:specific
The authorityName is a domain name or email address. The date is the date the type was issued in YYYY or YYYY-MM or YYYY-MM-DD format. The specific is a name for the type being added.
For example, built-in YAML types have ‘yaml.org’ as the authorityName and ‘2002’ as the date. The specific is simply the name of the type:
tag:yaml.org,2002:int tag:yaml.org,2002:float tag:yaml.org,2002:timestamp
The domain must be owned by you on the date declared. If you don’t own any domains on the date you declare the type, you can simply use an e-mail address.
tag:why@ruby-lang.org,2004:notes/personal
# File syck/lib/syck/tag.rb, line 35
def self.tag_class( tag, cls )
if @@tagged_classes.has_key? tag
warn "class #{ @@tagged_classes[tag] } held ownership of the #{ tag } tag"
end
@@tagged_classes[tag] = cls
end
Returns the complete dictionary of taguris, paired with classes. The key for the dictionary is the full taguri. The value for each key is the class constant associated to that taguri.
YAML.tagged_classes["tag:yaml.org,2002:int"] => Integer
# File syck/lib/syck/tag.rb, line 48
def self.tagged_classes
@@tagged_classes
end
Convert a type_id to a taguri
# File syck/lib/syck.rb, line 342
def self.tagurize( val )
warn "#{caller[0]}: YAML.tagurize is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
resolver.tagurize( val )
end
Apply a transfer method to a Ruby object
# File syck/lib/syck.rb, line 350
def self.transfer( type_id, obj )
warn "#{caller[0]}: YAML.transfer is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
resolver.transfer( tagurize( type_id ), obj )
end
Apply any implicit a node may qualify for
# File syck/lib/syck.rb, line 358
def self.try_implicit( obj )
warn "#{caller[0]}: YAML.try_implicit is deprecated" if $VERBOSE && !caller[0].start_with?(File.dirname(__FILE__))
transfer( detect_implicit( obj ), obj )
end
Unescape the condenses escapes
# File syck/lib/syck/encoding.rb, line 22
def self.unescape( value )
warn "#{caller[0]}: YAML.unescape is deprecated" if $VERBOSE
value.gsub( /\\(?:([nevfbart\\])|0?x([0-9a-fA-F]{2})|u([0-9a-fA-F]{4}))/ ) {
if $3
["#$3".hex ].pack('U*')
elsif $2
[$2].pack( "H2" )
else
UNESCAPES[$1]
end
}
end