class SPARQL::Algebra::Operator::In

The SPARQL GraphPattern `in` operator.

@example

(ask (filter (in 2 1 2 3) (bgp)))

@see www.w3.org/TR/sparql11-query/#func-in

Constants

NAME

Public Instance Methods

evaluate(bindings, **options) click to toggle source

The IN operator tests whether the RDF term on the left-hand side is found in the values of list of expressions on the right-hand side. The test is done with “=” operator, which tests for the same value, as determined by the operator mapping.

A list of zero terms on the right-hand side is legal.

Errors in comparisons cause the IN expression to raise an error if the RDF term being tested is not found elsewhere in the list of terms.

The IN operator is equivalent to the SPARQL expression:

(lhs = expression1) || (lhs = expression2) || ...

@example

2 IN (1, 2, 3) #=> true
2 IN () #=> false
2 IN (<http://example/iri>, "str", 2.0) #=> true
2 IN (1/0, 2) #=> true
2 IN (2, 1/0) #=> true
2 IN (3, 1/0) #=> raises an error

@param [RDF::Query::Solution] bindings

a query solution containing zero or more variable bindings

@param [Hash{Symbol => Object}] options ({})

options passed from query

@return [RDF::Literal::Boolean] `true` or `false` @raise [TypeError] if term is not found and any operand raises an error

# File lib/sparql/algebra/operator/in.rb, line 41
def evaluate(bindings, **options)
  lhs = operands.first.evaluate(bindings, **options)
  error_found = false
  found = operands[1..-1].any? do |op|
    begin
      lhs == op.evaluate(bindings, depth: options[:depth].to_i + 1, **options)
    rescue TypeError
      error_found = true
    end
  end
  case
  when found then RDF::Literal::TRUE
  when error_found then raise TypeError
  else RDF::Literal::FALSE
  end
end