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Diffstat (limited to 'lib/arel/visitors/reduce.rb')
-rw-r--r-- | lib/arel/visitors/reduce.rb | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/lib/arel/visitors/reduce.rb b/lib/arel/visitors/reduce.rb new file mode 100644 index 0000000000..9670cad27c --- /dev/null +++ b/lib/arel/visitors/reduce.rb @@ -0,0 +1,25 @@ +require 'arel/visitors/visitor' + +module Arel + module Visitors + class Reduce < Arel::Visitors::Visitor + def accept object, collector + visit object, collector + end + + private + + def visit object, collector + send dispatch[object.class], object, collector + rescue NoMethodError => e + raise e if respond_to?(dispatch[object.class], 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 |