Class: SPARQL::Algebra::Operator::LCase

Inherits:
Operator::Unary
  • Object
show all
Includes:
Evaluatable
Defined in:
lib/sparql/algebra/operator/lcase.rb

Overview

The SPARQL logical lcase operator.

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

Examples:

SPARQL Grammar

PREFIX : <http://example.org/>
SELECT ?s (LCASE(?str) AS ?lstr) WHERE {
  ?s :str ?str
}

SSE

(prefix ((: <http://example.org/>))
 (project (?s ?lstr)
  (extend ((?lstr (lcase ?str)))
   (bgp (triple ?s :str ?str)))))

See Also:

Constant Summary collapse

NAME = 
:lcase

Instance Method Summary collapse

Methods included from Evaluatable

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

Instance Method Details

#apply(operand, **options) ⇒ RDF::Literal

The LCASE function corresponds to the XPath fn:lower-case function. It returns a string literal whose lexical form is the lower case of the lexcial form of the argument.

Parameters:

  • operand (RDF::Literal) —

    the operand

Returns:

  • (RDF::Literal) —

    literal of same type

Raises:

  • (TypeError) —

    if the operand is not a literal value



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# File 'lib/sparql/algebra/operator/lcase.rb', line 34

def apply(operand, **options)
  case operand
    when RDF::Literal then RDF::Literal(operand.to_s.downcase, datatype: operand.datatype, language: operand.language)
    else raise TypeError, "expected an RDF::Literal::Numeric, but got #{operand.inspect}"
  end
end

#to_sparql(**options) ⇒ String

Returns a partial SPARQL grammar for this operator.

Returns:

  • (String) 


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# File 'lib/sparql/algebra/operator/lcase.rb', line 46

def to_sparql(**options)
  "LCASE(" + operands.last.to_sparql(**options) + ")"
end