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# frozen_string_literal: true
module Arel # :nodoc: all
module Visitors
class Visitor
def initialize
@dispatch = get_dispatch_cache
end
def accept(object, collector = nil)
visit object, collector
end
private
attr_reader :dispatch
def self.dispatch_cache
@dispatch_cache ||= Hash.new do |hash, klass|
hash[klass] = :"visit_#{(klass.name || "").gsub("::", "_")}"
end.compare_by_identity
end
def get_dispatch_cache
self.class.dispatch_cache
end
def visit(object, collector = nil)
dispatch_method = dispatch[object.class]
if collector
send dispatch_method, object, collector
else
send dispatch_method, object
end
rescue NoMethodError => e
raise e if respond_to?(dispatch_method, true)
superklass = object.class.ancestors.find { |klass|
respond_to?(dispatch[klass], true)
}
raise(TypeError, "Cannot visit #{object.class}") unless superklass
dispatch[object.class] = dispatch[superklass]
retry
end
end
end
end
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