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module SPARQL; module Algebra
class Operator
##
# The SPARQL logical `rand` operator.
#
# Returns a pseudo-random number between 0 (inclusive) and 1.0e0 (exclusive). Different numbers can be produced every time this function is invoked. Numbers should be produced with approximately equal probability.
#
# [121] BuiltInCall ::= ... | 'RAND' NIL
#
# @example SPARQL Grammar
# PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
# ASK {
# BIND(RAND() AS ?r)
# FILTER(DATATYPE(?r) = xsd:double && ?r >= 0.0 && ?r < 1.0)
# }
#
# @example SSE
# (prefix
# ((xsd: <http://www.w3.org/2001/XMLSchema#>))
# (ask
# (filter
# (&&
# (&& (= (datatype ?r) xsd:double) (>= ?r 0.0))
# (< ?r 1.0))
# (extend ((?r (rand)))
# (bgp)))))
#
# @see https://www.w3.org/TR/sparql11-query/#idp2130040
class Rand < Operator::Nullary
include Evaluatable
NAME = :rand
##
# Returns a pseudo-random number between 0 (inclusive) and 1.0e0 (exclusive). Different numbers can be produced every time this function is invoked. Numbers should be produced with approximately equal probability.
#
# @return [RDF::Literal::Double] random value
def apply(**options)
RDF::Literal::Double.new(Random.rand)
end
##
#
# Returns a partial SPARQL grammar for this operator.
#
# Extracts projections
#
# @return [String]
def to_sparql(**options)
"RAND()"
end
end # Rand
end # Operator
end; end # SPARQL::Algebra
Version data entries
8 entries across 8 versions & 1 rubygems