Class: SPARQL::Algebra::Operator::StrLang

Inherits:
Binary show all
Includes:
Evaluatable
Defined in:
lib/sparql/algebra/operator/strlang.rb

Overview

The SPARQL strlang operator.

[121] BuiltInCall ::= ... | 'STRLANG' '(' Expression ',' Expression ')'

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT ?s (STRLANG(?str,"en-US") AS ?s2) WHERE {
  ?s :str ?str
  FILTER(LANGMATCHES(LANG(?str), "en"))
}

SSE

(prefix ((: <http://example.org/>))
  (project (?s ?s2)
    (extend ((?s2 (strlang ?str "en-US")))
      (filter (langMatches (lang ?str) "en")
        (bgp (triple ?s :str ?str))))))

See Also:

Constant Summary collapse

NAME = 
:strlang

Constants inherited from Binary

Binary::ARITY

Constants inherited from SPARQL::Algebra::Operator

ARITY, IsURI, URI

Constants included from Expression

Expression::PATTERN_PARENTS

Instance Attribute Summary

Attributes inherited from SPARQL::Algebra::Operator

#operands

Instance Method Summary collapse

Methods included from Evaluatable

#evaluate, #memoize, #replace_aggregate!, #replace_vars!

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, #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

#apply(value, langTag, **options) ⇒ RDF::Literal

Constructs a literal with lexical form and type as specified by the arguments.

Parameters:

  • value (RDF::Literal) —

    a literal

  • langTag (RDF::Literal) —

    datatype

Returns:

  • (RDF::Literal) —

    a datatyped literal

Raises:

  • (TypeError)

See Also:



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# File 'lib/sparql/algebra/operator/strlang.rb', line 37

def apply(value, langTag, **options)
  raise TypeError, "Literal #{value.inspect} is not simple" unless value.simple?
  RDF::Literal.new(value.to_s, language: langTag.to_s)
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/strlang.rb', line 47

def to_sparql(**options)
  "STRLANG(" + operands.to_sparql(delimiter: ', ', **options) + ")"
end