From: "Phalado (Raphael Cordeiro) via ruby-core" <ruby-core@...>
Date: 2025-09-01T13:44:49+00:00
Subject: [ruby-core:123157] [Ruby Feature#21556] Add true? and false? methods to NilClass, TrueClass, FalseClass, and String

Issue #21556 has been updated by Phalado (Raphael Cordeiro).


austin (Austin Ziegler) wrote in #note-3:
> Phalado (Raphael Cordeiro) wrote in #note-2:
> > nobu (Nobuyoshi Nakada) wrote in #note-1:
> > > Phalado (Raphael Cordeiro) wrote:
> > > > Sometimes we need to check for an exact `true` or `false` value. This can be a string or a boolean value.
> > > For what situation, and why mixing strings and `true`/`false`?
> > > It sounds like depending on applications/libraries.
> > Data received on requests and JSON conversion. It's not unusual that a Boolean is converted to a String, or users end up filling in as a String instead of a Boolean.
> 
> If you're checking a string for the value `"true"`, you're not checking for an exact `true` or `false` value. This is a data conversion applicable to an application, library, or framework (that is, it might be a viable feature for ActiveSupport) but I don't believe it belongs as part of the language core.
> 
> I'm mostly doing Elixir these days where in a library I made I have explicitly handled this with an `as_boolean(value, options)` conversion where the options include choices like:
> 
> - which values are truthy (by default `true` or `1`)
> - which values are fasly (the inverse of `truthy` and cannot be specified with `truthy`)
> - a default value (`false` by default)
> - and whether values should be downcased (`TRUE` would be truthy)
> 
> Simply saying `value.true?` isn't something that the language should be specifying. What would the value of `0.true?` be (it depends; in shell scripts, `0` is success; in C, `0` is false; in Ruby `0` is truthy because it's not `false` or` nil`).
> 
> I'm very negative on this for core.

Well, the idea is to recognize true/false values, ignoring truthy/falsy values because of JSON.

But I respect your opinion and truly appreciate it.

----------------------------------------
Feature #21556: Add true? and false? methods to NilClass, TrueClass, FalseClass, and String
https://bugs.ruby-lang.org/issues/21556#change-114491

* Author: Phalado (Raphael Cordeiro)
* Status: Feedback
----------------------------------------
Sometimes we need to check for an exact `true` or `false` value. This can be a string or a boolean value.

Usually, what I do to solve this is something like `value.to_s == true`, this way covering for strings, booleans, and nil values.

The idea of these new methods is to check for the exact value, being it a String, a Boolean, or even a Nil value.

This is the result obtained:

``` ruby
# String

'true'.true? # true
'false'.true? # false
''.true? # false

'true'.false? # false
'false'.false? # true
''.false? # false

# Boolean

true.true? # true
true.false? # false

false.true? # false
false.false? # true

# Nil

nil.true? # false
nil.false? # false
```




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