require_relative '../../version1_0'
require_relative '../../relationship'

module BELParser
  module Language
    module Version1_0
      module Relationships
        # IsA:  +A isA B+ -  For terms A and B, +A isA B+ indicates
        # that A is a subset of B. All terms in BEL represent classes,
        # but given that classes implicitly have instances, one can
        # also interpret +A isA B+ to mean that any instance of A must
        # also be an instance of B. This relationship can be used to
        # represent GO and MeSH hierarchies: +pathology(MESH:Psoriasis)
        # isA pathology(MESH:"Skin Diseases")+
        class IsA
          extend Relationship

          SHORT       = :isA
          LONG        = :isA

          DESCRIPTION = <<-DOC
IsA:  +A isA B+ -  For terms A and B, +A isA B+ indicates
that A is a subset of B. All terms in BEL represent classes,
but given that classes implicitly have instances, one can
also interpret +A isA B+ to mean that any instance of A must
also be an instance of B. This relationship can be used to
represent GO and MeSH hierarchies: +pathology(MESH:Psoriasis)
isA pathology(MESH:"Skin Diseases")+
          DOC

          def self.short
            SHORT
          end

          def self.long
            LONG
          end

          def self.description
            DESCRIPTION
          end

          def self.directed?
            true
          end
        end
      end
    end
  end
end