class RDF::N3::Algebra::Math::Difference
The subject is a pair of numbers. The object is calculated by subtracting the second number of the pair from the first.
@example
{ ("8" "3") math:difference ?x} => { ?x :valueOf "8 - 3" } . { ("8") math:difference ?x } => { ?x :valueOf "8 - (error?)" } . { (8 3) math:difference ?x} => { ?x :valueOf "8 - 3" } .
Constants
- NAME
- URI
Public Instance Methods
resolve(list)
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The math:difference operator takes a pair of strings or numbers and calculates their difference.
@param [RDF::N3::List] list @return [RDF::Term] @see RDF::N3::ListOperator#evaluate
# File lib/rdf/n3/algebra/math/difference.rb, line 21 def resolve(list) list.to_a.map(&:as_number).reduce(&:-) end
validate(list)
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The list argument must be a pair of literals.
@param [RDF::N3::List] list @return [Boolean] @see RDF::N3::ListOperator#validate
Calls superclass method
RDF::N3::Algebra::ListOperator#validate
# File lib/rdf/n3/algebra/math/difference.rb, line 31 def validate(list) if super && list.all?(&:literal?) && list.length == 2 true else log_error(NAME) {"list is not a pair of literals: #{list.to_sxp}"} false end end