# -*- mode: ruby; ruby-indent-level: 4; tab-width: 4 -*- vim: sw=4 ts=4
# $Id: yaml.rb 16084 2008-04-19 11:45:39Z knu $
#
# = yaml.rb: top-level module with methods for loading and parsing YAML documents
#
# Author:: why the lucky stiff
#
require 'stringio'
require 'yaml/error'
require 'yaml/syck'
require 'yaml/tag'
require 'yaml/stream'
require 'yaml/constants'
# == YAML
#
# 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 http://yaml.org/ for more information. For a quick tutorial, please
# visit YAML In Five Minutes (http://yaml.kwiki.org/?YamlInFiveMinutes).
#
# == About This Library
#
# 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 (http://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).
#
# == Example
#
# 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
#
module YAML
Resolver = YAML::Syck::Resolver
DefaultResolver = YAML::Syck::DefaultResolver
DefaultResolver.use_types_at( @@tagged_classes )
GenericResolver = YAML::Syck::GenericResolver
Parser = YAML::Syck::Parser
Emitter = YAML::Syck::Emitter
# Returns a new default parser
def YAML.parser; Parser.new.set_resolver( YAML.resolver ); end
# Returns a new generic parser
def YAML.generic_parser; Parser.new.set_resolver( GenericResolver ); end
# Returns the default resolver
def YAML.resolver; DefaultResolver; end
# Returns a new default emitter
def YAML.emitter; Emitter.new.set_resolver( YAML.resolver ); 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"
#
def YAML.dump( obj, io = nil )
obj.to_yaml( io || io2 = StringIO.new )
io || ( io2.rewind; io2.read )
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
#
def YAML.load( io )
yp = parser.load( io )
end
#
# Load a document from the file located at _filepath_.
#
# YAML.load_file( 'animals.yaml' )
# #=> ['badger', 'elephant', 'tiger']
#
def YAML.load_file( filepath )
File.open( filepath ) do |f|
load( f )
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>
#
def YAML.parse( io )
yp = generic_parser.load( io )
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">]>
#
def YAML.parse_file( filepath )
File.open( filepath ) do |f|
parse( f )
end
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
#
def YAML.each_document( io, &block )
yp = parser.load_documents( io, &block )
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
#
def YAML.load_documents( io, &doc_proc )
YAML.each_document( io, &doc_proc )
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
#
def YAML.each_node( io, &doc_proc )
yp = generic_parser.load_documents( io, &doc_proc )
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
#
def YAML.parse_documents( io, &doc_proc )
YAML.each_node( io, &doc_proc )
end
#
# Loads all documents from the current _io_ stream,
# returning a +YAML::Stream+ object containing all
# loaded documents.
#
def YAML.load_stream( io )
d = nil
parser.load_documents( io ) do |doc|
d = YAML::Stream.new if not d
d.add( doc )
end
return d
end
#
# Returns a YAML stream containing each of the items in +objs+,
# each having their own document.
#
# YAML.dump_stream( 0, [], {} )
# #=> --- 0
# --- []
# --- {}
#
def YAML.dump_stream( *objs )
d = YAML::Stream.new
objs.each do |doc|
d.add( doc )
end
d.emit
end
#
# Add a global handler for a YAML domain type.
#
def YAML.add_domain_type( domain, type_tag, &transfer_proc )
resolver.add_type( "tag:#{ domain }:#{ type_tag }", transfer_proc )
end
#
# Add a transfer method for a builtin type
#
def YAML.add_builtin_type( type_tag, &transfer_proc )
resolver.add_type( "tag:yaml.org,2002:#{ type_tag }", transfer_proc )
end
#
# Add a transfer method for a builtin type
#
def YAML.add_ruby_type( type_tag, &transfer_proc )
resolver.add_type( "tag:ruby.yaml.org,2002:#{ type_tag }", transfer_proc )
end
#
# Add a private document type
#
def YAML.add_private_type( type_re, &transfer_proc )
resolver.add_type( "x-private:" + type_re, transfer_proc )
end
#
# Detect typing of a string
#
def YAML.detect_implicit( val )
resolver.detect_implicit( val )
end
#
# Convert a type_id to a taguri
#
def YAML.tagurize( val )
resolver.tagurize( val )
end
#
# Apply a transfer method to a Ruby object
#
def YAML.transfer( type_id, obj )
resolver.transfer( YAML.tagurize( type_id ), obj )
end
#
# Apply any implicit a node may qualify for
#
def YAML.try_implicit( obj )
YAML.transfer( YAML.detect_implicit( obj ), obj )
end
#
# Method to extract colon-seperated type and class, returning
# the type and the constant of the class
#
def YAML.read_type_class( type, obj_class )
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
#
# Allocate blank object
#
def YAML.object_maker( obj_class, val )
if Hash === val
o = obj_class.allocate
val.each_pair { |k,v|
o.instance_variable_set("@#{k}", v)
}
o
else
raise YAML::Error, "Invalid object explicitly tagged !ruby/Object: " + val.inspect
end
end
#
# Allocate an Emitter if needed
#
def YAML.quick_emit( oid, opts = {}, &e )
out =
if opts.is_a? YAML::Emitter
opts
else
emitter.reset( opts )
end
oid =
case oid when Fixnum, NilClass; oid
else oid = "#{oid.object_id}-#{oid.hash}"
end
out.emit( oid, &e )
end
end
require 'yaml/rubytypes'
require 'yaml/types'
module Kernel
#
# ryan:: You know how Kernel.p is a really convenient way to dump ruby
# structures? The only downside is that it's not as legible as
# YAML.
#
# _why:: (listening)
#
# ryan:: I know you don't want to urinate all over your users' namespaces.
# But, on the other hand, convenience of dumping for debugging is,
# IMO, a big YAML use case.
#
# _why:: Go nuts! Have a pony parade!
#
# ryan:: Either way, I certainly will have a pony parade.
#
# Prints any supplied _objects_ out in YAML. Intended as
# a variation on +Kernel::p+.
#
# S = Struct.new(:name, :state)
# s = S['dave', 'TX']
# y s
#
# _produces:_
#
# --- !ruby/struct:S
# name: dave
# state: TX
#
def y( object, *objects )
objects.unshift object
puts( if objects.length == 1
YAML::dump( *objects )
else
YAML::dump_stream( *objects )
end )
end
private :y
end
