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Contents
module SPARQL; module Algebra
class Operator
##
# The SPARQL logical `not` operator.
#
# [118] UnaryExpression ::= ... | '!' PrimaryExpression
#
# @example SPARQL Grammar
# PREFIX : <http://example.org/ns#>
# SELECT ?a
# WHERE {
# ?a :p ?v .
# FILTER ( ! ?v ) .
# }
#
# @example SSE
# (prefix ((: <http://example.org/ns#>))
# (project (?a)
# (filter (! ?v)
# (bgp (triple ?a :p ?v)))))
#
# @see https://www.w3.org/TR/xpath-functions/#func-not
class Not < Operator::Unary
include Evaluatable
NAME = [:'!', :not]
##
# Returns the logical `NOT` (inverse) of the operand.
#
# Note that this operator operates on the effective boolean value
# (EBV) of its operand.
#
# @param [RDF::Literal::Boolean] operand
# the operand
# @return [RDF::Literal::Boolean] `true` or `false`
# @raise [TypeError] if the operand could not be coerced to a boolean literal
def apply(operand, **options)
case bool = boolean(operand)
when RDF::Literal::Boolean
RDF::Literal(bool.false?)
else super
end
end
##
#
# Returns a partial SPARQL grammar for this operator.
#
# @return [String]
def to_sparql(**options)
"(!" + operands.first.to_sparql(**options) + ")"
end
end # Not
end # Operator
end; end # SPARQL::Algebra
Version data entries
8 entries across 8 versions & 1 rubygems