[ruby-core:43671] [ruby-trunk - Feature #1400] Please add a method to enumerate fields in OpenStruct

Issue #1400 has been updated by marcandre (Marc-Andre Lafortune).


Hi,

Peter Vandenabeele wrote:
>  Is there a specified order for the enumeration? (I presume not, but
>  curious).

As the implementation uses a hash, it would be the same order, i.e. order in which they were set.

Thomas Sawyer wrote:
> If #each_pair, why not #each?

The nice thing about `each_pair` is that is common to both Hash and Struct and would have the same meaning for OpenStruct. `Struct#each` yields only the values, so that might cause some confusion?

> It was also recommended to me to suggest #to_h here.

I think it would be nice to have this, and not only in OpenStruct. Matz seems positive about it too [ruby-core:43363].

Here's what I have so far:
https://github.com/marcandre/ruby/compare/ostruct

----------------------------------------
Feature #1400: Please add a method to enumerate fields in OpenStruct
https://bugs.ruby-lang.org/issues/1400#change-25170

Author: tpo (Tomas Pospisek)
Status: Assigned
Priority: Normal
Assignee: marcandre (Marc-Andre Lafortune)
Category: lib
Target version: 2.0.0


=begin
 There are two ways to find out what fields an OpenStruct instance has. One is through inspect,
 however that returns a String that needs to be parsed.
 
 The second is by white box engineering, looking at OpenStructs source code and seeing that in
 fact, it has a hash and getting the keys of that hash...
 
 The second way is faster, more robust, but will break once OpenStruct will be re-engineered...
 
 So I suggest to add an explicit method to return a list of fields in an OpenStruct instance:
 
 --- ostruct.rb.old	2009-04-23 15:26:45.000000000 +0200
 +++ ostruct.rb	2009-04-23 15:32:41.000000000 +0200
 @@ -110,6 +110,15 @@
      @table.delete name.to_sym
    end
  
 +  #
 +  # Returns an Array containing the fields of an OpenStruct instance
 +  #
 +  # p record.fields # -> [:age, :pension, :name]
 +  #
 +  def fields
 +    @table.keys
 +  end
 +
    InspectKey = :__inspect_key__ # :nodoc:
  
    #
=end



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