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module SPARQL; module Algebra
class Operator
##
# The SPARQL `strlang` operator.
#
# [121] BuiltInCall ::= ... | 'STRLANG' '(' Expression ',' Expression ')'
#
# @example SPARQL Grammar
# PREFIX : <http://example.org/>
# SELECT ?s (STRLANG(?str,"en-US") AS ?s2) WHERE {
# ?s :str ?str
# FILTER(LANGMATCHES(LANG(?str), "en"))
# }
#
# @example 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 https://www.w3.org/TR/sparql11-query/#func-strlang
class StrLang < Operator::Binary
include Evaluatable
NAME = :strlang
##
# Constructs a literal with lexical form and type as specified by the arguments.
#
# @param [RDF::Literal] value
# a literal
# @param [RDF::Literal] langTag
# datatype
# @return [RDF::Literal] a datatyped literal
# @see https://www.w3.org/TR/sparql11-query/#func-strlang
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
##
#
# Returns a partial SPARQL grammar for this operator.
#
# @return [String]
def to_sparql(**options)
"STRLANG(" + operands.to_sparql(delimiter: ', ', **options) + ")"
end
end # StrLang
end # Operator
end; end # SPARQL::Algebra
Version data entries
7 entries across 7 versions & 1 rubygems