Class: SPARQL::Algebra::Operator::Project

Inherits:

Binary

• Object
• SPARQL::Algebra::Operator
• Binary
• SPARQL::Algebra::Operator::Project

show all

Includes:

Query

Defined in:

lib/sparql/algebra/operator/project.rb

Overview

(select (?v)
  (project (?v)
    (filter (= ?v 2)
      (bgp (triple ?s <http://example/p> ?v)))))

Constant Summary

NAME =

[:project]

Constants inherited from Binary

Binary::ARITY

Constants inherited from SPARQL::Algebra::Operator

ARITY

Instance Attribute Summary

Attributes included from Query

#solutions

Attributes inherited from SPARQL::Algebra::Operator

#operands, #options

Instance Method Summary (collapse)

• - (RDF::Query::Solutions) execute(queryable, options = {})

  Executes this query on the given queryable graph or repository.

• - (Union, RDF::Query) optimize

  Returns an optimized version of this query.

Methods included from Query

#context=, #each_solution, #failed?, #matched?, #unshift, #variables

Methods inherited from Binary

#initialize

Methods inherited from SPARQL::Algebra::Operator

arity, base_uri, #base_uri, base_uri=, #boolean, #constant?, #eql?, #evaluatable?, evaluate, #executable?, for, #initialize, #inspect, #operand, prefixes, #prefixes, prefixes=, #to_sse, #to_sxp, #variable?

Methods included from Evaluatable

#apply, #evaluate, #memoize

Methods included from Expression

cast, #constant?, #evaluate, for, new, open, parse, #to_sse, #variable?

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# File 'lib/sparql/algebra/operator/project.rb', line 29

def execute(queryable, options = {})
  @solutions = operands.last.
    execute(queryable, options.merge(:depth => options[:depth].to_i + 1)).
    project(*(operands.first))
end

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# File 'lib/sparql/algebra/operator/project.rb', line 41

def optimize
  operands = operands.map(&:optimize)
end