CODEWITHSUNDEEP
ruby
Hubro
Hubro

Reputation: 59343

Are default argument expressions evaluated even when the arguments are provided?

I have read that in Ruby, default argument expressions are evaluated for every function call. However, if I have a function like this:

def foo(bar=super_heavy_work())
  # ...
end

And call it like this:

foo "default argument not needed"

I have now provided a function argument, so my question is: is the super heavy work function called in this case, or is it skipped since the default value isn't needed?

Upvotes: 4

Views: 722

Answers (1)

August
August

Reputation: 12558

No, default value expressions are not evaluated if you pass an argument:

def foo
  puts 'called foo!'
end

def bar(n = foo)
  puts 'called bar!'
end

bar
# => called foo!
# => called bar!

bar("some value")
# => called bar!

The same goes for keyword arguments:

def foo
  puts 'called foo!'
end

def bar(n: foo)
  puts 'called bar!'
end

bar
# => called foo!
# => called bar!

bar(n: "some value")
# => called bar!

Upvotes: 6

Related Questions