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module SPARQL; module Algebra
class Operator
##
# The SPARQL GraphPattern `distinct` operator.
#
# [9] SelectClause ::= 'SELECT' ( 'DISTINCT' | 'REDUCED' )? ( ( Var | ( '(' Expression 'AS' Var ')' ) )+ | '*' )
#
# @example SPARQL Grammar
# PREFIX : <http://example.org/>
# PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
# SELECT DISTINCT ?v
# WHERE { ?x ?p ?v }
#
# @example SSE
# (prefix ((: <http://example.org/>)
# (xsd: <http://www.w3.org/2001/XMLSchema#>))
# (distinct
# (project (?v)
# (bgp (triple ?x ?p ?v)))))
#
# @see https://www.w3.org/TR/sparql11-query/#sparqlDistinct
class Distinct < Operator::Unary
include Query
NAME = [:distinct]
##
# Executes this query on the given `queryable` graph or repository.
# Removes duplicate solutions from the solution set.
#
# @param [RDF::Queryable] queryable
# the graph or repository to query
# @param [Hash{Symbol => Object}] options
# any additional keyword options
# @yield [solution]
# each matching solution
# @yieldparam [RDF::Query::Solution] solution
# @yieldreturn [void] ignored
# @return [RDF::Query::Solutions]
# the resulting solution sequence
# @see https://www.w3.org/TR/sparql11-query/#sparqlAlgebra
def execute(queryable, **options, &block)
@solutions = queryable.query(operands.last, **options.merge(depth: options[:depth].to_i + 1)).distinct
@solutions.each(&block) if block_given?
@solutions
end
##
#
# Returns a partial SPARQL grammar for this operator.
#
# @return [String]
def to_sparql(**options)
operands.first.to_sparql(distinct: true, **options)
end
end # Distinct
end # Operator
end; end # SPARQL::Algebra
Version data entries
4 entries across 4 versions & 1 rubygems