utils/zaml.rb
# encoding: ASCII-8BIT
#
# ZAML -- A partial replacement for YAML, writen with speed and code clarity
# in mind. ZAML fixes one YAML bug (loading Exceptions) and provides
# a replacement for YAML.dump() unimaginatively called ZAML.dump(),
# which is faster on all known cases and an order of magnitude faster
# with complex structures.
#
# http://github.com/hallettj/zaml
#
# Authors: Markus Roberts, Jesse Hallett, Ian McIntosh, Igal Koshevoy, Simon Chiang
#
#require 'yaml'
class ZAML
VERSION = "0.1.1"
#
# Class Methods
#
def self.dump(stuff, where='')
z = new
stuff.to_zaml(z)
where << z.to_s
end
#
# Instance Methods
#
def initialize
@result = []
@indent = nil
@structured_key_prefix = nil
Label.counter_reset
emit('--- ')
end
def nested(tail=' ')
old_indent = @indent
@indent = "#{@indent || "\n"}#{tail}"
yield
@indent = old_indent
end
class Label
#
# YAML only wants objects in the datastream once; if the same object
# occurs more than once, we need to emit a label ("&idxxx") on the
# first occurrence and then emit a back reference (*idxxx") on any
# subsequent occurrence(s).
#
# To accomplish this we keeps a hash (by object id) of the labels of
# the things we serialize as we begin to serialize them. The labels
# initially serialize as an empty string (since most objects are only
# going to be be encountered once), but can be changed to a valid
# (by assigning it a number) the first time it is subsequently used,
# if it ever is. Note that we need to do the label setup BEFORE we
# start to serialize the object so that circular structures (in
# which we will encounter a reference to the object as we serialize
# it can be handled).
#
def self.counter_reset
@@previously_emitted_object = {}
@@next_free_label_number = 0
end
def initialize(obj,indent)
@indent = indent
@this_label_number = nil
@@previously_emitted_object[obj.object_id] = self
end
def to_s
@this_label_number ? ('&id%03d%s' % [@this_label_number, @indent]) : ''
end
def reference
@this_label_number ||= (@@next_free_label_number += 1)
@reference ||= '*id%03d' % @this_label_number
end
def self.for(obj)
@@previously_emitted_object[obj.object_id]
end
end
def new_label_for(obj)
Label.new(obj,(Hash === obj || Array === obj) ? "#{@indent || "\n"} " : ' ')
end
def first_time_only(obj)
if label = Label.for(obj)
emit(label.reference)
else
if @structured_key_prefix and not obj.is_a? String
emit(@structured_key_prefix)
@structured_key_prefix = nil
end
emit(new_label_for(obj))
yield
end
end
def emit(s)
@result << s
@recent_nl = false unless s.kind_of?(Label)
end
def nl(s='')
emit(@indent || "\n") unless @recent_nl
emit(s)
@recent_nl = true
end
def to_s
@result.join
end
def prefix_structured_keys(x)
@structured_key_prefix = x
yield
nl unless @structured_key_prefix
@structured_key_prefix = nil
end
end
################################################################
#
# Behavior for custom classes
#
################################################################
class Object
def to_yaml_properties
instance_variables.sort # Default YAML behavior
end
def zamlized_class_name(root)
"!ruby/#{root.name.downcase}#{self.class == root ? '' : ":#{self.class.name}"}"
end
def to_zaml(z)
z.first_time_only(self) {
z.emit(zamlized_class_name(Object))
z.nested {
instance_variables = to_yaml_properties
if instance_variables.empty?
z.emit(" {}")
else
instance_variables.each { |v|
z.nl
v[1..-1].to_zaml(z) # Remove leading '@'
z.emit(': ')
instance_variable_get(v).to_zaml(z)
}
end
}
}
end
end
################################################################
#
# Behavior for built-in classes
#
################################################################
class NilClass
def to_zaml(z)
z.emit('') # NOTE: blank turns into nil in YAML.load
end
end
class Symbol
def to_zaml(z)
z.emit(self.inspect)
end
end
class TrueClass
def to_zaml(z)
z.emit('true')
end
end
class FalseClass
def to_zaml(z)
z.emit('false')
end
end
class Numeric
def to_zaml(z)
z.emit(self)
end
end
class Regexp
def to_zaml(z)
z.first_time_only(self) { z.emit("#{zamlized_class_name(Regexp)} #{inspect}") }
end
end
class Exception
def to_zaml(z)
z.emit(zamlized_class_name(Exception))
z.nested {
z.nl("message: ")
message.to_zaml(z)
}
end
#
# Monkey patch for buggy Exception restore in YAML
#
# This makes it work for now but is not very future-proof; if things
# change we'll most likely want to remove this. To mitigate the risks
# as much as possible, we test for the bug before appling the patch.
#
if respond_to? :yaml_new and yaml_new(self, :tag, "message" => "blurp").message != "blurp"
def self.yaml_new( klass, tag, val )
o = YAML.object_maker( klass, {} ).exception(val.delete( 'message'))
val.each_pair do |k,v|
o.instance_variable_set("@#{k}", v)
end
o
end
end
end
class String
ZAML_ESCAPES = %w{\x00 \x01 \x02 \x03 \x04 \x05 \x06 \a \x08 \t \n \v \f \r \x0e \x0f \x10 \x11 \x12 \x13 \x14 \x15 \x16 \x17 \x18 \x19 \x1a \e \x1c \x1d \x1e \x1f }
def escaped_for_zaml
gsub( /\x5C/, "\\\\\\" ). # Demi-kludge for Maglev/rubinius; the regexp should be /\\/ but parsetree chokes on that.
gsub( /"/, "\\\"" ).
gsub( /([\x00-\x1F])/ ) { |x| ZAML_ESCAPES[ x.unpack("C")[0] ] }.
gsub( /([\x80-\xFF])/ ) { |x| "\\x#{x.unpack("C")[0].to_s(16)}" }
end
def to_zaml(z)
z.first_time_only(self) {
num = '[-+]?(0x)?\d+\.?\d*'
case
when self == ''
z.emit('""')
# when self =~ /[\x00-\x08\x0B\x0C\x0E-\x1F\x80-\xFF]/
# z.emit("!binary |\n")
# z.emit([self].pack("m*"))
when (
(self =~ /\A(true|false|yes|no|on|null|off|#{num}(:#{num})*|!|=|~)$/i) or
(self =~ /\A\n* /) or
(self =~ /\s$/) or
(self =~ /^[>|][-+\d]*\s/i) or
(self[-1..-1] =~ /\s/) or
(self =~ /[\x00-\x08\x0B\x0C\x0E-\x1F\x80-\xFF]/) or
(self =~ /[,\[\]\{\}\r\t]|:\s|\s#/) or
(self =~ /\A([-:?!#&*'"]|<<|%.+:.)/)
)
z.emit("\"#{escaped_for_zaml}\"")
when self =~ /\n/
if self[-1..-1] == "\n" then z.emit('|+') else z.emit('|-') end
z.nested { split("\n",-1).each { |line| z.nl; z.emit(line.chomp("\n")) } }
z.nl
else
z.emit(self)
end
}
end
end
class Hash
def to_zaml(z)
z.first_time_only(self) {
z.nested {
if empty?
z.emit('{}')
else
each_pair { |k, v|
z.nl
z.prefix_structured_keys('? ') { k.to_zaml(z) }
z.emit(': ')
v.to_zaml(z)
}
end
}
}
end
end
class Array
def to_zaml(z)
z.first_time_only(self) {
z.nested {
if empty?
z.emit('[]')
else
each { |v| z.nl('- '); v.to_zaml(z) }
end
}
}
end
end
class Time
def to_zaml(z)
# 2008-12-06 10:06:51.373758 -07:00
ms = ("%0.6f" % (usec * 1e-6)).sub(/^\d+\./,'')
offset = "%+0.2i:%0.2i" % [utc_offset / 3600, (utc_offset / 60) % 60]
z.emit(self.strftime("%Y-%m-%d %H:%M:%S.#{ms} #{offset}"))
end
end
class Date
def to_zaml(z)
z.emit(strftime('%Y-%m-%d'))
end
end
class Range
def to_zaml(z)
z.first_time_only(self) {
z.emit(zamlized_class_name(Range))
z.nested {
z.nl
z.emit('begin: ')
z.emit(first)
z.nl
z.emit('end: ')
z.emit(last)
z.nl
z.emit('excl: ')
z.emit(exclude_end?)
}
}
end
end