Sha256: 542cffe310f8f0f18898985b8e717a2ad51ebee49e1c4fff6103206631762209
Contents?: true
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Versions: 5
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Stored size: 1.04 KB
Contents
require 'rdf'
module RDF
class List
##
# Validate the list ensuring that
# * rdf:rest values are all BNodes are nil
# * rdf:type, if it exists, is rdf:List
# * each subject has no properties other than single-valued rdf:first, rdf:rest
# other than for the first node in the list
# @return [Boolean]
def valid?
li = subject
while li != RDF.nil do
rest = nil
firsts = rests = 0
@graph.query(:subject => li) do |st|
case st.predicate
when RDF.type
# Be tollerant about rdf:type entries, as some OWL vocabularies use it excessively
when RDF.first
firsts += 1
when RDF.rest
rest = st.object
return false unless rest.node? || rest == RDF.nil
rests += 1
else
# First node may have other properties
return false unless li == subject
end
end
return false unless firsts == 1 && rests == 1
li = rest
end
true
end
end
end
Version data entries
5 entries across 5 versions & 1 rubygems