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Feature #21389

closed

Simplify Set#inspect output

Added by jeremyevans0 (Jeremy Evans) about 1 month ago. Updated 6 days ago.

Status:
Closed
Assignee:
-
Target version:
-
[ruby-core:122355]

Description

As Set is now a core collection class, it should have special inspect output. Ideally, inspect output should be suitable to eval, similar to array and hash (assuming the elements are also suitable to eval):

set = Set[1, 2, 3]
eval(set.inspect) == set # should be true

The simplest way to do this is to use the Set[] syntax:

Set[1, 2, 3].inspect
# => "Set[1, 2, 3]"

I've submitted a pull request that implements this: https://github.com/ruby/ruby/pull/13488

The pull request deliberately does not use any subclass name in the output, similar to array and hash. I think it is more important that users know they are dealing with a set than which subclass:

Class.new(Set)[]
# PR does: Set[]
#     not: #<Class:0x00000c21c78699e0>[]

However, it's easy to change the PR to use a subclass name if that is desired.


Related issues 1 (0 open1 closed)

Related to Ruby - Bug #21377: core Set#inspect does not use inherited class nameClosedActions
Actions #1

Updated by Eregon (Benoit Daloze) 29 days ago

  • Related to Bug #21377: core Set#inspect does not use inherited class name added

Updated by Eregon (Benoit Daloze) 29 days ago

Per https://bugs.ruby-lang.org/issues/21377#note-5 (that issue should have been linked BTW, I added it),
I strongly believe showing Set[1, 2, 3] instead of MySet[1, 2, 3] for an instance of MySet would be a mistake.

Array and Hash don't show the class name at all, then sure obviously they don't show the subclass name either.
No inspect, if it shows the class name, should ever show the wrong class name, i.e., not obj.class.inspect, that would just be intentional confusion and there is no reason for that.

The example with an anonymous subclass is unrepresentative of realistic usages so hardly matters in comparison.

BTW here is an example of a core class showing the subclass name:

class MyModule < Module; end
p MyModule.new # => #<MyModule:0x00007f4e318e3ad8>

Updated by matz (Yukihiro Matsumoto) 26 days ago

I prefer Set[1, 2, 3] to #<Set: {1, 2, 3}>. And the name of the subclass should be printed, e.g. MySet[1, 2, 3].

Matz.

Actions #4

Updated by jeremyevans (Jeremy Evans) 6 days ago

  • Status changed from Open to Closed

Applied in changeset git|3a9c091cf393e8a9c4e4b93d4216f2be3678e488.


Simplify Set#inspect output

As Set is now a core collection class, it should have special inspect
output. Ideally, inspect output should be suitable to eval, similar
to array and hash (assuming the elements are also suitable to eval):

set = Set[1, 2, 3]
eval(set.inspect) == set # should be true

The simplest way to do this is to use the Set[] syntax.

This deliberately does not use any subclass name in the output,
similar to array and hash. It is more important that users know they
are dealing with a set than which subclass:

Class.new(Set)[]

this does: Set[]

not: #Class:0x00000c21c78699e0[]

This inspect change breaks the power_assert bundled gem tests, so
add power_assert to TEST_BUNDLED_GEMS_ALLOW_FAILURES in the workflows.

Implements [Feature #21389]

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