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Comment by shevy-java | Hacker News Reader

I don't really like the API design. Perhaps in the rails-world this makes sense, but it looks really strange to me.

    Billing::Plan::Factory.find_or_create_by!(
      name: :pro,
      interval: 1.month,
      amount: 50
    )

It is not only the verbosity or use of trailing '!' in a method for no real reason, IMO, but also things such as "1.month". I understand that rails thrives as a DSL, but to me having a method such as .month on an Integer, is simply wrong. Same with HashWithIndifferentAccess - I understand the point, to not have to care whether a key is a String or a Symbol, but it is simply the wrong way to think about this. People who use HashWithIndifferentAccess do not understand Symbols.

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The exclamation mark has a reason: if the newly created records fails validations, an exception is raised. Without the exclamation mark, the error is silenced (and the method returns a falsey value). This is a convention across Rails.

Ruby itself mostly uses it for mutating methods (e.g. #gsub("a", "b") replaces the character a with b in a string and returns a new string, but #gsub!("a", "b") mutates the original.

> I understand that rails thrives as a DSL, but to me having a method such as .month on an Integer, is simply wrong

It's not that different from `1.times` or `90.chr` which are vanilla Ruby.

> HashWithIndifferentAccess

HashWithIndifferentAccess was an unfortunate necessity to avoid DOS attacks when Symbols used to be immortal. There's no longer a reason to use it today, except for backward compatibility.

when *everything* is an object this kind of syntax makes absolutely sense and is quite convenient

my first thought too, as a rubyist.

Yes, "everything is an object" is an essential insight to understanding ruby.

`1 + 1` in Ruby is syntactic sugar for `1.+(1)`. Nothing wrong about it at all, it's just different from what you're apparently used to. This type of thing isn't even unique to Ruby or even OOP.

This is a typical API design in Ruby, but the post is about a somewhat novel API design than what you're pointing out. To address some of your points:

The exclamation mark is a convention. It is used whenever a method could possibly result in an exception being raised. Sometimes it's instead used for non-idempotent methods.

"3.days", etc are Rails things. A lot of non-Rubyists don't like it but once you use it for long enough you tend to really grow to it.

As for HashWithIndifferentAccess, yes this is generally acknowledged as a mistake in Ruby's design and is rarely used in my experience. Originally, all Ruby hashes were HWIA. When they finally realized this was a design mistake they had to create HWIA for some level of backwards compatibility

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