Question

I am reading along in pickaxe 1.9 and the author uses lambda like this:

bo = lambda {|param| puts "You called me with #{param}"}
bo.call 99     => 'You called me with 99'
bo.call "cat"  => 'You called me with cat'

My question is this: How is this any better/worse/different than just defining a method that does that same thing? Like so:

def bo(param)
  puts "You called me with #{param}"
end

bo("hello") => 'You called me with hello'

To me the lambda syntax seems much more confusing and spaghetti-like.

Answer 1

Lambdas:

• are variations of Procs,
• can be converted to/from blocks,
• do not begin a new closure scope (meaning you can access variables defined outside the scope of your lambda, unlike def),
• can be passed around as variables.

I recommend checking out this article that explain procs, blocks, and lambdas.

Edit: This link is outdated. For future reference, try this article