Can we overide true and false methods in Ruby?

user_7365329 0
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Is it possibile to override boolean method like true and false in Ruby?

For example

def true
   rand()
end

def false
   rand()
end

true  #=> 0.7548583661438558
false #=> 0.19239076750079454

If I try the above, I get:

true  #=> true
false #=> false

I'm trying to understand where these true, false methods are defined.

I know that && and || can't be overriden, because && and || are short circut operators.

Are true and false similar? or they are written inside Ruby somewhere?

I'm just experimenting with Ruby.

overriding boolean ruby
1 Answers

true and false cannot be overridden because they are keywords, not methods. Their values are hard-coded and there's no way to re-assign a different value. (at least not from within Ruby)

Even when implementing a method with the same name, a literal true will still resolve to the built-in value.

What you can do is change the object, true is resolving to for interesting results: (this is just for fun, don't do this in actual code)

def true.inspect
  rand.to_s
end

true #=> 0.8499100640573652
true #=> 0.22279583303254913

However, the above example doesn't actually change the value of true in any way. Also, don't think of true as a method invocation returning a random float every time it is called. We are looking at the very same object:

a = true

a #=> 0.5813338288658235
a #=> 0.6447125630746154

What we did is change its representation by overriding inspect, which:

Returns a string containing a human-readable representation of obj.

We see those floats because IRB calls inspect in an attempt to print the last expression's result in a readable way.

If we set IRB's output mode to :to_s, our change is bypassed and we see true again:

IRB.CurrentContext.inspect_mode = :to_s

a    #=> true
true #=> true
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