Class: SPARQL::Algebra::Operator::Seq
- Inherits:
-
Binary
- Object
- SPARQL::Algebra::Operator
- Binary
- SPARQL::Algebra::Operator::Seq
- Includes:
- Query
- Defined in:
- lib/sparql/algebra/operator/seq.rb
Overview
The SPARQL Property Path sequence
(SequencePath) operator.
[90] PathSequence ::= PathEltOrInverse ( ‘/’ PathEltOrInverse )*
Constant Summary collapse
- NAME =
:seq
Constants inherited from Binary
Constants inherited from SPARQL::Algebra::Operator
Constants included from Expression
Instance Attribute Summary
Attributes included from Query
Attributes inherited from SPARQL::Algebra::Operator
Instance Method Summary collapse
-
#execute(queryable, **options) {|solution| ... } ⇒ Object
Join solution sets.
-
#to_sparql(**options) ⇒ String
Returns a partial SPARQL grammar for this operator.
Methods included from Query
#each_solution, #empty?, #failed?, #graph_name=, #matched?, #query_yields_boolean?, #query_yields_solutions?, #query_yields_statements?, #unshift, #variables
Methods inherited from Binary
Methods inherited from SPARQL::Algebra::Operator
#aggregate?, arity, #base_uri, base_uri, base_uri=, #bind, #boolean, #constant?, #deep_dup, #each_descendant, #eql?, #evaluatable?, evaluate, #executable?, #first_ancestor, for, #initialize, #inspect, #ndvars, #node?, #operand, #optimize, #optimize!, #parent, #parent=, #prefixes, prefixes, prefixes=, #rewrite, #to_binary, to_sparql, #to_sxp, #to_sxp_bin, #validate!, #variable?, #variables, #vars
Methods included from Expression
cast, #constant?, #evaluate, extension, extension?, extensions, for, #invalid?, new, #node?, open, #optimize, #optimize!, parse, register_extension, #to_sxp_bin, #valid?, #validate!, #variable?
Constructor Details
This class inherits a constructor from SPARQL::Algebra::Operator::Binary
Instance Method Details
#execute(queryable, **options) {|solution| ... } ⇒ Object
Join solution sets
(path :x (seq :p :q) :y) => (join (bgp (:x :p ??1)) (bgp (??1 :q :y)))
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# File 'lib/sparql/algebra/operator/seq.rb', line 41 def execute(queryable, **, &block) subject, object = [:subject], [:object] debug() {"Seq #{[subject, operands, object].to_sse}"} v = RDF::Query::Variable.new(distinguished: false) q1 = if operand(0).is_a?(RDF::Term) RDF::Query.new do |q| q.pattern [subject, operand(0), v] end else operand(0) end q2 = if operand(1).is_a?(RDF::Term) RDF::Query.new do |q| q.pattern [v, operand(1), object] end else operand(1) end left = queryable.query(q1, **.merge(object: v, depth: [:depth].to_i + 1)) #debug(options) {"(seq)=>(left) #{left.map(&:to_h).to_sse}"} right = queryable.query(q2, **.merge(subject: v, depth: [:depth].to_i + 1)) #debug(options) {"(seq)=>(right) #{right.map(&:to_h).to_sse}"} @solutions = RDF::Query::Solutions(left.map do |s1| right.map do |s2| s2.merge(s1) if s2.compatible?(s1) end end.flatten.compact).map do |solution| solution.bindings.delete(v.to_sym) solution end debug() {"(seq)=> #{@solutions.to_sxp}"} @solutions.each(&block) if block_given? @solutions end |
#to_sparql(**options) ⇒ String
Returns a partial SPARQL grammar for this operator.
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# File 'lib/sparql/algebra/operator/seq.rb', line 85 def to_sparql(**) '(' + operands.to_sparql(delimiter: '/', **) + ')' end |