Class: SPARQL::Algebra::Operator::Base

Inherits:
Binary show all
Includes:
Query
Defined in:
lib/sparql/algebra/operator/base.rb

Overview

The SPARQL GraphPattern base operator.

[5] BaseDecl ::= ‘BASE’ IRIREF

Examples:

SPARQL Grammar

BASE <http://example.org/>
SELECT * { <a> <b> 123.0 }

SSE

(base <http://example.org/>
  (bgp (triple <a> <b> 123.0)))

See Also:

Constant Summary collapse

NAME = 
[:base]

Constants inherited from Binary

SPARQL::Algebra::Operator::Binary::ARITY

Constants inherited from SPARQL::Algebra::Operator

ARITY, IsURI, URI

Constants included from Expression

Expression::PATTERN_PARENTS

Instance Attribute Summary

Attributes included from Query

#solutions

Attributes inherited from SPARQL::Algebra::Operator

#operands

Instance Method Summary collapse

Methods included from Query

#each_solution, #empty?, #failed?, #graph_name=, #matched?, #query_yields_solutions?, #unshift, #variables

Methods inherited from Binary

#initialize

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!, #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!, 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| ... } ⇒ RDF::Queryable, RDF::Query::Solutions

Executes this query on the given queryable graph or repository. Really a pass-through, as this is a syntactic object used for providing context for relative URIs.

Parameters:

  • queryable (RDF::Queryable) —

    the graph or repository to query

  • options (Hash{Symbol => Object}) —

    any additional keyword options

Yields:

  • (solution) —

    each matching solution, statement or boolean

Yield Parameters:

Yield Returns:

  • (void) —

    ignored

Returns:

See Also:



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# File 'lib/sparql/algebra/operator/base.rb', line 38

def execute(queryable, **options, &block)
  debug(options) {"Base #{operands.first}"}
  Operator.base_uri = operands.first
  queryable.query(operands.last, **options.merge(depth: options[:depth].to_i + 1), &block)
end

#optimize(**options) ⇒ Base

Return optimized query

Returns:

  • (Base) —

    a copy of self

See Also:



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# File 'lib/sparql/algebra/operator/base.rb', line 49

def optimize(**options)
  Operator.base_uri = operands.first
  operands.last.optimize(**options)
end

#query_yields_boolean? ⇒ Boolean

Query results in a boolean result (e.g., ASK)

Returns:

  • (Boolean) 


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# File 'lib/sparql/algebra/operator/base.rb', line 56

def query_yields_boolean?
  operands.last.query_yields_boolean?
end

#query_yields_statements? ⇒ Boolean

Query results statements (e.g., CONSTRUCT, DESCRIBE, CREATE)

Returns:

  • (Boolean) 


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# File 'lib/sparql/algebra/operator/base.rb', line 62

def query_yields_statements?
  operands.last.query_yields_statements?
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this term.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/base.rb', line 71

def to_sparql(**options)
  str = "BASE #{operands.first.to_sparql}\n"

  str << operands.last.to_sparql(base_uri: operands.first, **options)
end