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require 'digest'
module SPARQL; module Algebra
class Operator
##
# The SPARQL logical `sha256` operator.
#
# Returns the SHA256 checksum, as a hex digit string, calculated on the UTF-8 representation of the simple literal or lexical form of the `xsd:string`. Hex digits `SHOULD` be in lower case.
#
# @example
# (prefix ((: <http://example.org/>))
# (project (?hash)
# (extend ((?hash (sha256 ?l)))
# (bgp (triple :s1 :str ?l)))))
#
# @see http://www.w3.org/TR/sparql11-query/#func-sha256
class SHA256 < Operator::Unary
include Evaluatable
NAME = :sha256
##
# Returns the SHA256 checksum, as a hex digit string, calculated on the UTF-8 representation of the simple literal or lexical form of the xsd:string. Hex digits should be in lower case.
#
# @param [RDF::Literal] operand
# the operand
# @return [RDF::Literal]
# @raise [TypeError] if the operand is not a simple literal
def apply(operand)
raise TypeError, "expected an RDF::Literal, but got #{operand.inspect}" unless operand.literal?
raise TypeError, "expected simple literal or xsd:string, but got #{operand.inspect}" unless (operand.datatype || RDF::XSD.string) == RDF::XSD.string
RDF::Literal(Digest::SHA256.new.hexdigest(operand.to_s))
end
end # SHA256
end # Operator
end; end # SPARQL::Algebra
Version data entries
11 entries across 11 versions & 1 rubygems