Pattern matching APIs for records and relations. #45070
Conversation
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cc @gmcgibbon since you kindly merged the last one |
This provides the Ruby 2.7+ pattern matching interface for Active Record
records and relations. It allows the user to pattern match against
attributes and associations on records through a hash pattern. It also
allows the user to pattern match against relations through an array pattern.
```ruby
class Post < ActiveRecord::Base
has_many :comments
end
class Comment < ActiveRecord::Base
belongs_to :post
end
post = Post.new(title: "Welcome!", comments: [Comment.new(body: "Thanks!")])
post => { title: "Welcome!", comments: [Comment[body:]] }
body # => "Thanks!"
```
*Kevin Newton*
kddnewton
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What's the status of this? Still blocked? I've been using this in production and it's working great. |
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Here you can read the status of this #45553 (comment) |
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@rafaelfranca, I saw that but @kddnewton hasn't gotten a response in nearly a month. I agree with his reasoning. Would hate to see this get lost. I don't see a problem with the current API. |
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We don't need to rush a decision here. Rails 7.1 isn't due any time soon and this feature would only be release in Rails 7.1. Rushing a making the wrong decision will just cause trouble for us maintainers, so it is better to make sure we have considered all possibilities. |
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Understood, @rafaelfranca. Is there a location where this discussion is taking place? |
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In the meantime, I've released a gem https://github.com/kddnewton/rails-pattern_matching that encapsulates this pattern. Folks can maybe use that to prototype/test what they think is the right approach. Hopefully that will help aid in a decision. |
| # person = Person.new | ||
| # person.name = "Bob" | ||
| # greeting_for(person) # => "Welcome, stranger!" | ||
| def deconstruct_keys(keys) |
There was a problem hiding this comment.
(Sorry, just passing by.)
Note that keys might be nil, if somebody does this:
case person
in name: 'Mary', **attributes
Rails.logger.info "Mary logged in. Currently set of attrs are: #{attributes}"
endThere was a problem hiding this comment.
Yeah, I handled that in the gem I mentioned. I wasn't sure if this PR was moving anywhere so I'm waiting to hear on this.
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I'm not doing anything fancy, just destructuring rightward assignment, and the gem is working great for that purpose!
rec = MyRecord.find(id)
# Destructuring Rightward Assignment
# See: https://www.fullstackruby.dev/ruby-3-fundamentals/2021/01/06/everything-you-need-to-know-about-destructuring-in-ruby-3/
rec => {
organization_id:,
group_id:,
source_id:,
patch_id:,
report_id:,
}
# and now I have all those local variables to work with, pulled directly from my records' attributes.
I have noticed that it only works with true attributes, so if I create an accessor method I can't pull that value through (yet).
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@pboling that's expected. If you have any other feedback on the gem though feel free to open an issue on the gem repo itself
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For my own work-tracking purposes I'm going to close this PR, but I will continue to maintain the gem. If there comes a time where rails would like to consider pattern matching, give me a shout! |
This provides the Ruby 2.7+ pattern matching interface for Active Record
records and relations. It allows the user to pattern match against
attributes and associations on records through a hash pattern. It also
allows the user to pattern match against relations through an array pattern.