require 'haml'
require 'cgi'
require 'rdf/xsd'
module RDF::RDFa
##
# An RDFa 1.1 serialiser in Ruby. The RDFa serializer makes use of Haml templates, allowing runtime-replacement with alternate templates. Note, however, that templates should be checked against the W3C test suite to ensure that valid RDFa is emitted.
#
# Note that the natural interface is to write a whole graph at a time. Writing statements or Triples will create a graph to add them to and then serialize the graph.
#
# The writer will add prefix definitions, and use them for creating @prefix definitions, and minting CURIEs
#
# @example Obtaining a RDFa writer class
# RDF::Writer.for(:html) => RDF::RDFa::Writer
# RDF::Writer.for("etc/test.html")
# RDF::Writer.for(file_name: "etc/test.html")
# RDF::Writer.for(file_extension: "html")
# RDF::Writer.for(content_type: "application/xhtml+xml")
# RDF::Writer.for(content_type: "text/html")
#
# @example Serializing RDF graph into an XHTML+RDFa file
# RDF::RDFa::Write.open("etc/test.html") do |writer|
# writer << graph
# end
#
# @example Serializing RDF statements into an XHTML+RDFa file
# RDF::RDFa::Writer.open("etc/test.html") do |writer|
# graph.each_statement do |statement|
# writer << statement
# end
# end
#
# @example Serializing RDF statements into an XHTML+RDFa string
# RDF::RDFa::Writer.buffer do |writer|
# graph.each_statement do |statement|
# writer << statement
# end
# end
#
# @example Creating @base and @prefix definitions in output
# RDF::RDFa::Writer.buffer(base_uri: "http://example.com/", prefixes: {
# foaf: "http://xmlns.com/foaf/0.1/"}
# ) do |writer|
# graph.each_statement do |statement|
# writer << statement
# end
# end
#
# @author [Gregg Kellogg](http://kellogg-assoc.com/)
class Writer < RDF::Writer
format RDF::RDFa::Format
include RDF::Util::Logger
# Defines rdf:type of subjects to be emitted at the beginning of the document.
# @return [Array<URI>]
attr :top_classes
# Defines order of predicates to to emit at begninning of a resource description. Defaults to `[rdf:type, rdfs:label, dc:title]`
# @return [Array<URI>]
attr :predicate_order
# Defines order of predicates to use in heading.
# @return [Array<URI>]
attr :heading_predicates
HAML_OPTIONS = {
format: :xhtml
}
# @return [Graph] Graph of statements serialized
attr_accessor :graph
# @return [RDF::URI] Base URI used for relativizing URIs
attr_accessor :base_uri
##
# RDFa Writer options
# @see http://www.rubydoc.info/github/ruby-rdf/rdf/RDF/Writer#options-class_method
def self.options
super + [
RDF::CLI::Option.new(
symbol: :lang,
datatype: String,
on: ["--lang"],
description: "Output as root @lang attribute, and avoid generation _@lang_ where possible."),
]
end
##
# Initializes the RDFa writer instance.
#
# @param [IO, File] output
# the output stream
# @param [Hash{Symbol => Object}] options
# any additional options
# @option options [Boolean] :canonicalize (false)
# whether to canonicalize literals when serializing
# @option options [Hash] :prefixes (Hash.new)
# the prefix mappings to use
# @option options [#to_s] :base_uri (nil)
# the base URI to use when constructing relative URIs, set as html>head>base.href
# @option options [Boolean] :validate (false)
# whether to validate terms when serializing
# @option options [#to_s] :lang (nil)
# Output as root @lang attribute, and avoid generation _@lang_ where possible
# @option options [Boolean] :standard_prefixes (false)
# Add standard prefixes to _prefixes_, if necessary.
# @option options [Array<RDF::URI>] :top_classes ([RDF::RDFS.Class])
# Defines rdf:type of subjects to be emitted at the beginning of the document.
# @option options [Array<RDF::URI>] :predicate_order ([RDF.type, RDF::RDFS.label, RDF::Vocab::DC.title])
# Defines order of predicates to to emit at begninning of a resource description..
# @option options [Array<RDF::URI>] :heading_predicates ([RDF::RDFS.label, RDF::Vocab::DC.title])
# Defines order of predicates to use in heading.
# @option options [String, Symbol, Hash{Symbol => String}] :haml (DEFAULT_HAML) HAML templates used for generating code
# @option options [Hash] :haml_options (HAML_OPTIONS)
# Options to pass to Haml::Engine.new.
# @yield [writer]
# @yieldparam [RDF::Writer] writer
def initialize(output = $stdout, options = {}, &block)
super do
@uri_to_term_or_curie = {}
@uri_to_prefix = {}
@top_classes = options[:top_classes] || [RDF::RDFS.Class]
@predicate_order = options[:predicate_order] || [RDF.type, RDF::RDFS.label, RDF::URI("http://purl.org/dc/terms/title")]
@heading_predicates = options[:heading_predicates] || [RDF::RDFS.label, RDF::URI("http://purl.org/dc/terms/title")]
@graph = RDF::Graph.new
block.call(self) if block_given?
end
end
# @return [Hash<Symbol => String>]
def haml_template
return @haml_template if @haml_template
case @options[:haml]
when Symbol, String then HAML_TEMPLATES.fetch(@options[:haml].to_sym, DEFAULT_HAML)
when Hash then @options[:haml]
else DEFAULT_HAML
end
end
##
# Addes a triple to be serialized
# @param [RDF::Resource] subject
# @param [RDF::URI] predicate
# @param [RDF::Value] object
# @return [void]
# @raise [NotImplementedError] unless implemented in subclass
# @abstract
# @raise [RDF::WriterError] if validating and attempting to write an invalid {RDF::Term}.
def write_triple(subject, predicate, object)
@graph.insert(RDF::Statement(subject, predicate, object))
end
##
# Outputs the XHTML+RDFa representation of all stored triples.
#
# @return [void]
def write_epilogue
@base_uri = RDF::URI(@options[:base_uri]) if @options[:base_uri]
@lang = @options[:lang]
self.reset
log_debug {"\nserialize: graph size: #{@graph.size}"}
preprocess
# Prefixes
prefix = prefixes.keys.map {|pk| "#{pk}: #{prefixes[pk]}"}.sort.join(" ") unless prefixes.empty?
log_debug {"\nserialize: prefixes: #{prefix.inspect}"}
subjects = order_subjects
# Take title from first subject having a heading predicate
doc_title = nil
titles = {}
heading_predicates.each do |pred|
@graph.query(predicate: pred) do |statement|
titles[statement.subject] ||= statement.object
end
end
title_subject = subjects.detect {|subject| titles[subject]}
doc_title = titles[title_subject]
# Generate document
doc = render_document(subjects,
lang: @lang,
base: base_uri,
title: doc_title,
prefix: prefix) do |s|
subject(s)
end
@output.write(doc)
super
end
protected
# Render document using `haml_template[:doc]`. Yields each subject to be rendered separately.
#
# @param [Array<RDF::Resource>] subjects
# Ordered list of subjects. Template must yield to each subject, which returns
# the serialization of that subject (@see #subject_template)
# @param [Hash{Symbol => Object}] options Rendering options passed to Haml render.
# @option options [RDF::URI] base (nil)
# Base URI added to document, used for shortening URIs within the document.
# @option options [Symbol, String] language (nil)
# Value of @lang attribute in document, also allows included literals to omit
# an @lang attribute if it is equivalent to that of the document.
# @option options [String] title (nil)
# Value of html>head>title element.
# @option options [String] prefix (nil)
# Value of @prefix attribute.
# @option options [String] haml (haml_template[:doc])
# Haml template to render.
# @yield [subject]
# Yields each subject
# @yieldparam [RDF::URI] subject
# @yieldreturn [:ignored]
# @return String
# The rendered document is returned as a string
def render_document(subjects, options = {})
template = options[:haml] || :doc
options = {
prefix: nil,
subjects: subjects,
title: nil,
}.merge(options)
hamlify(template, options) do |subject|
yield(subject) if block_given?
end.gsub(/^\s+$/m, '')
end
# Render a subject using `haml_template[:subject]`.
#
# The _subject_ template may be called either as a top-level element, or recursively under another element if the _rel_ local is not nil.
#
# Yields each predicate/property to be rendered separately (@see #render_property_value and `#render_property_values`).
#
# @param [Array<RDF::Resource>] subject
# Subject to render
# @param [Array<RDF::Resource>] predicates
# Predicates of subject. Each property is yielded for separate rendering.
# @param [Hash{Symbol => Object}] options Rendering options passed to Haml render.
# @option options [String] about (nil)
# About description, a CURIE, URI or Node definition.
# May be nil if no @about is rendered (e.g. unreferenced Nodes)
# @option options [String] resource (nil)
# Resource description, a CURIE, URI or Node definition.
# May be nil if no @resource is rendered
# @option options [String] rel (nil)
# Optional @rel property description, a CURIE, URI or Node definition.
# @option options [String] typeof (nil)
# RDF type as a CURIE, URI or Node definition.
# If :about is nil, this defaults to the empty string ("").
# @option options [:li, nil] element (nil)
# Render with <li>, otherwise with template default.
# @option options [String] haml (haml_template[:subject])
# Haml template to render.
# @yield [predicate]
# Yields each predicate
# @yieldparam [RDF::URI] predicate
# @yieldreturn [:ignored]
# @return String
# The rendered document is returned as a string
# Return Haml template for document from `haml_template[:subject]`
def render_subject(subject, predicates, options = {})
template = options[:haml] || :subject
options = {
about: (get_curie(subject) unless options[:rel]),
base: base_uri,
element: nil,
predicates: predicates,
rel: nil,
inlist: nil,
resource: (get_curie(subject) if options[:rel]),
subject: subject,
typeof: nil,
}.merge(options)
hamlify(template, options) do |predicate|
yield(predicate) if block_given?
end
end
# Render a single- or multi-valued predicate using `haml_template[:property_value]` or `haml_template[:property_values]`. Yields each object for optional rendering. The block should only render for recursive subject definitions (i.e., where the object is also a subject and is rendered underneath the first referencing subject).
#
# If a multi-valued property definition is not found within the template, the writer will use the single-valued property definition multiple times.
#
# @param [Array<RDF::Resource>] predicate
# Predicate to render.
# @param [Array<RDF::Resource>] objects
# List of objects to render. If the list contains only a single element, the :property_value template will be used. Otherwise, the :property_values template is used.
# @param [Hash{Symbol => Object}] options Rendering options passed to Haml render.
# @option options [String] :haml (haml_template[:property_value], haml_template[:property_values])
# Haml template to render. Otherwise, uses `haml_template[:property_value] or haml_template[:property_values]`
# depending on the cardinality of objects.
# @yield object, inlist
# Yields object and if it is contained in a list.
# @yieldparam [RDF::Resource] object
# @yieldparam [Boolean] inlist
# @yieldreturn [String, nil]
# The block should only return a string for recursive object definitions.
# @return String
# The rendered document is returned as a string
def render_property(predicate, objects, options = {}, &block)
log_debug {"render_property(#{predicate}): #{objects.inspect}, #{options.inspect}"}
# If there are multiple objects, and no :property_values is defined, call recursively with
# each object
template = options[:haml]
template ||= objects.length > 1 ? haml_template[:property_values] : haml_template[:property_value]
# Separate out the objects which are lists and render separately
list_objects = objects.reject do |o|
o == RDF.nil ||
(l = RDF::List.new(subject: o, graph: @graph)).invalid?
end
unless list_objects.empty?
# Render non-list objects
log_debug {"properties with lists: #{list_objects} non-lists: #{objects - list_objects}"}
nl = log_depth {render_property(predicate, objects - list_objects, options, &block)} unless objects == list_objects
return nl.to_s + list_objects.map do |object|
# Render each list as multiple properties and set :inlist to true
list = RDF::List.new(subject: object, graph: @graph)
list.each_statement {|st| subject_done(st.subject)}
log_debug {"list: #{list.inspect} #{list.to_a}"}
log_depth do
render_property(predicate, list.to_a, options.merge(inlist: "true")) do |object|
yield(object, true) if block_given?
end
end
end.join(" ")
end
if objects.length > 1 && template.nil?
# If there is no property_values template, render each property using property_value template
objects.map do |object|
log_depth {render_property(predicate, [object], options, &block)}
end.join(" ")
else
log_fatal("Missing property template", exception: RDF::WriterError) if template.nil?
template = options[:haml] || (
objects.to_a.length > 1 &&
haml_template.has_key?(:property_values) ?
:property_values :
:property_value)
options = {
objects: objects,
object: objects.first,
predicate: predicate,
property: get_curie(predicate),
rel: get_curie(predicate),
inlist: nil,
}.merge(options)
hamlify(template, options, &block)
end
end
# Perform any preprocessing of statements required
# @return [ignored]
def preprocess
# Load initial contexts
# Add terms and prefixes to local store for converting URIs
# Keep track of vocabulary from left-most context
[XML_RDFA_CONTEXT, HTML_RDFA_CONTEXT].each do |uri|
ctx = Context.find(uri)
ctx.prefixes.each_pair do |k, v|
@uri_to_prefix[v] = k unless k.to_s == "dcterms"
end
ctx.terms.each_pair do |k, v|
@uri_to_term_or_curie[v] = k.to_s
end
@vocabulary = ctx.vocabulary.to_s if ctx.vocabulary
end
# Load defined prefixes
(@options[:prefixes] || {}).each_pair do |k, v|
@uri_to_prefix[v.to_s] = k
end
@options[:prefixes] = {} # Will define actual used when matched
# Process each statement to establish CURIEs and Terms
@graph.each {|statement| preprocess_statement(statement)}
end
# Order subjects for output. Override this to output subjects in another order.
#
# Uses #top_classes and #base_uri.
# @return [Array<Resource>] Ordered list of subjects
def order_subjects
seen = {}
subjects = []
# Start with base_uri
if base_uri && @subjects.keys.include?(base_uri)
subjects << base_uri
seen[base_uri] = true
end
# Add distinguished classes
top_classes.
select {|s| !seen.include?(s)}.
each do |class_uri|
graph.query(predicate: RDF.type, object: class_uri).map {|st| st.subject}.sort.uniq.each do |subject|
#log_debug {"order_subjects: #{subject.inspect}"}
subjects << subject
seen[subject] = true
end
end
# Sort subjects by resources over nodes, ref_counts and the subject URI itself
recursable = @subjects.keys.
select {|s| !seen.include?(s)}.
map {|r| [r.is_a?(RDF::Node) ? 1 : 0, ref_count(r), r]}.
sort
log_debug {"order_subjects: #{recursable.inspect}"}
subjects += recursable.map{|r| r.last}
end
# Take a hash from predicate uris to lists of values.
# Sort the lists of values. Return a sorted list of properties.
#
# @param [Hash{String => Array<Resource>}] properties A hash of Property to Resource mappings
# @return [Array<String>}] Ordered list of properties. Uses predicate_order.
def order_properties(properties)
# Make sorted list of properties
prop_list = []
predicate_order.each do |prop|
next unless properties[prop.to_s]
prop_list << prop.to_s
end
properties.keys.sort.each do |prop|
next if prop_list.include?(prop.to_s)
prop_list << prop.to_s
end
log_debug {"order_properties: #{prop_list.join(', ')}"}
prop_list
end
# Perform any statement preprocessing required. This is used to perform reference counts and determine required prefixes.
# @param [RDF::Statement] statement
# @return [ignored]
def preprocess_statement(statement)
#log_debug {"preprocess: #{statement.inspect}"}
bump_reference(statement.object)
@subjects[statement.subject] = true
get_curie(statement.subject)
get_curie(statement.predicate)
get_curie(statement.object)
get_curie(statement.object.datatype) if statement.object.literal? && statement.object.has_datatype?
end
# Reset parser to run again
def reset
@options[:log_depth] = 0
prefixes = {}
@references = {}
@serialized = {}
@subjects = {}
end
protected
# Display a subject.
#
# If the Haml template contains an entry matching the subject's rdf:type URI, that entry will be used as the template for this subject and it's properties.
#
# @example Displays a subject as a Resource Definition:
# <div typeof="rdfs:Resource" about="http://example.com/resource">
# <h1 property="dc:title">label</h1>
# <ul>
# <li content="2009-04-30T06:15:51Z" property="dc:created">2009-04-30T06:15:51+00:00</li>
# </ul>
# </div>
#
# @param [RDF::Resource] subject
# @param [Hash{Symbol => Object}] options
# @option options [:li, nil] :element(:div)
# Serialize using <li> rather than template default element
# @option options [RDF::Resource] :rel (nil)
# Optional @rel property
# @return [String]
def subject(subject, options = {})
return if is_done?(subject)
subject_done(subject)
properties = properties_for_subject(subject)
typeof = type_of(properties.delete(RDF.type.to_s), subject)
prop_list = order_properties(properties)
log_debug {"props: #{prop_list.inspect}"}
render_opts = {typeof: typeof, property_values: properties}.merge(options)
render_subject_template(subject, prop_list, render_opts)
end
# @param [RDF::Resource] subject
# @return [Hash{String => Object}]
def properties_for_subject(subject)
properties = {}
@graph.query(subject: subject) do |st|
key = st.predicate.to_s.freeze
properties[key] ||= []
properties[key] << st.object
end
properties
end
# @param [Array,NilClass] type
# @param [RDF::Resource] subject
# @return [String] string representation of the specific RDF.type uri
def type_of(type, subject)
# Find appropriate template
curie = case
when subject.node?
subject.to_s if ref_count(subject) > 1
else
get_curie(subject)
end
typeof = Array(type).map {|r| get_curie(r)}.join(" ")
typeof = nil if typeof.empty?
# Nodes without a curie need a blank @typeof to generate a subject
typeof ||= "" unless curie
log_debug {"subject: #{curie.inspect}, typeof: #{typeof.inspect}" }
typeof.freeze
end
# @param [RDF::Resource] subject
# @param [Array] prop_list
# @param [Hash] render_opts
# @return [String]
def render_subject_template(subject, prop_list, render_opts)
# See if there's a template based on the sorted concatenation of all types of this subject
# or any type of this subject
tmpl = find_template(subject)
log_debug {"subject: found template #{tmpl[:identifier] || tmpl.inspect}"} if tmpl
# Render this subject
# If :rel is specified and :typeof is nil, use @resource instead of @about.
# Pass other options from calling context
with_template(tmpl) do
render_subject(subject, prop_list, render_opts) do |pred|
log_depth do
pred = RDF::URI(pred) if pred.is_a?(String)
values = render_opts[:property_values][pred.to_s]
log_debug {"subject: #{get_curie(subject)}, pred: #{get_curie(pred)}, values: #{values.inspect}"}
predicate(pred, values)
end
end
end
end
# Write a predicate with one or more values.
#
# Values may be a combination of Literal and Resource (Node or URI).
# @param [RDF::Resource] predicate
# Predicate to serialize
# @param [Array<RDF::Resource>] objects
# Objects to serialize
# @return [String]
def predicate(predicate, objects)
log_debug {"predicate: #{predicate.inspect}, objects: #{objects}"}
return if objects.to_a.empty?
log_debug {"predicate: #{get_curie(predicate)}"}
render_property(predicate, objects) do |o, inlist=nil|
# Yields each object, for potential recursive definition.
# If nil is returned, a leaf is produced
log_depth {subject(o, rel: get_curie(predicate), inlist: inlist, element: (:li if objects.length > 1 || inlist))} if !is_done?(o) && @subjects.include?(o)
end
end
# Haml rendering helper. Return CURIE for the literal datatype, if the literal is a typed literal.
#
# @param [RDF::Resource] literal
# @return [String, nil]
# @raise [RDF::WriterError]
def get_dt_curie(literal)
if literal.is_a?(RDF::Literal)
get_curie(literal.datatype) if literal.literal? && literal.datatype?
else
log_error("Getting datatype CURIE for #{literal.inspect}, which must be a literal")
nil
end
end
# Haml rendering helper. Return language for plain literal, if there is no language, or it is the same as the document, return nil
#
# @param [RDF::Literal] literal
# @return [Symbol, nil]
# @raise [RDF::WriterError]
def get_lang(literal)
if literal.is_a?(RDF::Literal)
literal.language if literal.literal? && literal.language && literal.language.to_s != @lang.to_s
else
log_error("Getting language for #{literal.inspect}, which must be a literal")
nil
end
end
# Haml rendering helper. Data to be added to a @content value, for specific datatypes
#
# @param [RDF::Literal] literal
# @return [String, nil]
# @raise [RDF::WriterError]
def get_content(literal)
case literal
when RDF::Literal::Date, RDF::Literal::Time, RDF::Literal::DateTime, RDF::Literal::Duration
literal.to_s
when RDF::Literal then nil
else
log_error("Getting content for #{literal.inspect}, which must be a literal")
nil
end
end
# Haml rendering helper. Display value for object, may be humanized into a non-canonical form
#
# @param [RDF::Literal] literal
# @return [String]
# @raise [RDF::WriterError]
def get_value(literal)
if literal.is_a?(RDF::Literal)
literal.humanize
else
log_error("Getting value for #{literal.inspect}, which must be a literal")
nil
end
end
# Haml rendering helper. Return an appropriate label for a resource.
#
# @param [RDF::Resource] resource
# @return [String]
# @raise [RDF::WriterError]
def get_predicate_name(resource)
if resource.is_a?(RDF::URI)
get_curie(resource)
else
log_error("Getting predicate name for #{resource.inspect}, which must be a URI")
nil
end
end
# Haml rendering helper. Return appropriate, term, CURIE or URI for the given resource.
#
# @param [RDF::Value] resource
# @return [String] value to use to identify URI
# @raise [RDF::WriterError]
def get_curie(resource)
case resource
when RDF::URI
begin
uri = resource.to_s
curie = case
when @uri_to_term_or_curie.has_key?(uri)
log_debug {"get_curie(#{uri}): uri_to_term_or_curie #{@uri_to_term_or_curie[uri].inspect}"}
return @uri_to_term_or_curie[uri]
when base_uri && uri.index(base_uri.to_s) == 0
log_debug {"get_curie(#{uri}): base_uri (#{uri.sub(base_uri.to_s, "")})"}
uri.sub(base_uri.to_s, "")
when @vocabulary && uri.index(@vocabulary) == 0
log_debug {"get_curie(#{uri}): vocabulary"}
uri.sub(@vocabulary, "")
when u = @uri_to_prefix.keys.detect {|u| uri.index(u.to_s) == 0}
log_debug {"get_curie(#{uri}): uri_to_prefix"}
# Use a defined prefix
prefix = @uri_to_prefix[u]
prefix(prefix, u) # Define for output
uri.sub(u.to_s, "#{prefix}:")
when @options[:standard_prefixes] && vocab = RDF::Vocabulary.detect {|v| uri.index(v.to_uri.to_s) == 0}
log_debug {"get_curie(#{uri}): standard_prefixes"}
prefix = vocab.__name__.to_s.split('::').last.downcase
prefix(prefix, vocab.to_uri) # Define for output
uri.sub(vocab.to_uri.to_s, "#{prefix}:")
else
log_debug {"get_curie(#{uri}): none"}
uri
end
#log_debug {"get_curie(#{resource}) => #{curie}"}
@uri_to_term_or_curie[uri] = curie
rescue ArgumentError => e
log_error("Invalid URI #{uri.inspect}: #{e.message}")
nil
end
when RDF::Node then resource.to_s
when RDF::Literal then nil
else
log_error("Getting CURIE for #{resource.inspect}, which must be a resource")
nil
end
end
private
##
# Haml rendering helper. Escape entities to avoid whitespace issues.
#
# # In addtion to "&<>, encode \n and \r to ensure that whitespace is properly preserved
#
# @param [String] str
# @return [String]
# Entity-encoded string
def escape_entities(str)
CGI.escapeHTML(str).gsub(/[\n\r]/) {|c| '&#x' + c.unpack('h').first + ';'}
end
# Set the template to use within block
# @param [Hash{Symbol => String}] templ template to use for block evaluation; merged in with the existing template.
# @yield
# Yields with no arguments
# @yieldreturn [Object] returns the result of yielding
# @return [Object]
def with_template(templ)
if templ
new_template = @options[:haml].
reject {|k,v| ![:subject, :property_value, :property_values, :rel].include?(k)}.
merge(templ || {})
old_template, @haml_template = @haml_template, new_template
else
old_template = @haml_template
end
res = yield
# Restore template
@haml_template = old_template
res
end
# Render HAML
# @param [Symbol, String] template
# If a symbol, finds a matching template from haml_template, otherwise uses template as is
# @param [Hash{Symbol => Object}] locals
# Locals to pass to render
# @return [String]
# @raise [RDF::WriterError]
def hamlify(template, locals = {})
log_debug {"hamlify template: #{template}"}
template = haml_template[template] if template.is_a?(Symbol)
template = template.align_left
log_debug {"hamlify locals: #{locals.inspect}"}
Haml::Engine.new(template, @options[:haml_options] || HAML_OPTIONS).render(self, locals) do |*args|
yield(*args) if block_given?
end
rescue Haml::Error => e
log_fatal("#{e.inspect}\n" +
"rendering #{template}\n" +
"with options #{(@options[:haml_options] || HAML_OPTIONS).inspect}\n" +
"and locals #{locals.inspect}",
exception: RDF::WriterError
)
end
##
# Find a template appropriate for the subject.
# Override this method to provide templates based on attributes of a given subject
#
# @param [RDF::URI] subject
# @return [Hash] # return matched matched template
def find_template(subject); end
# Mark a subject as done.
# @param [RDF::Resource] subject
# @return [Boolean]
def subject_done(subject)
@serialized[subject] = true
end
# Determine if the subject has been completed
# @param [RDF::Resource] subject
# @return [Boolean]
def is_done?(subject)
@serialized.include?(subject)
end
# Increase the reference count of this resource
# @param [RDF::Resource] resource
# @return [Integer] resulting reference count
def bump_reference(resource)
@references[resource] = ref_count(resource) + 1
end
# Return the number of times this node has been referenced in the object position
# @param [RDF::Node] node
# @return [Boolean]
def ref_count(node)
@references.fetch(node, 0)
end
end
end
require 'rdf/rdfa/writer/haml_templates'