Feature #7349

Struct#inspect needs more meaningful output

Added by Hal Brodigan over 1 year ago. Updated over 1 year ago.

[ruby-core:49328]
Status:Assigned
Priority:Low
Assignee:Yukihiro Matsumoto
Category:core
Target version:next minor

Description

When inheriting directly from Struct.new, Class#ancestors shows a meaningless anonymous Class:

class Point < Struct.new(:x, :y)

  def distance
    ((x ** 2) + (y ** 2)) ** 0.5
  end

end

Point.ancestors
# => [Point, #<Class:0x007fe204a1a228>, Struct, Enumerable, Object, Kernel, BasicObject]

Perhaps, the anonymous Class could list the Struct's fields?

#<Class:x, y>

History

#1 Updated by Shyouhei Urabe over 1 year ago

Sounds nice to me. +1

#2 Updated by Clay Trump over 1 year ago

I like it too. Could even be:

 Point.ancestors
 # => [Point, Struct.new(:x, :y), Struct, Enumerable, Object, Kernel,

BasicObject]

--

#3 Updated by Benoit Daloze over 1 year ago

It might be worth pointing out that this should not happen if the Struct generated class is assigned to a constant (and so one level of inheritance is not unused):

Point = Struct.new(:x, :y) do
def distance
Math.hypot(x,y)
end
end

#4 Updated by Yusuke Endoh over 1 year ago

  • Tracker changed from Bug to Feature

#5 Updated by Yusuke Endoh over 1 year ago

  • Status changed from Open to Assigned
  • Assignee set to Yukihiro Matsumoto

#6 Updated by Yusuke Endoh over 1 year ago

This is not a bug. This ticket has been moved to the feature tracker.

I'm not against this proposal, but I don't think that people normally check the singleton class to know Struct fields. You may want to use Struct.#members:

p Point.members #=> [:x, :y]

It is shorter than ancestors.

Yusuke Endoh mame@tsg.ne.jp

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