Question

I checked out the latest Ruby version, to play a bit with the latest changes. The first thing I tried to do was call a Ruby lambda/block/proc just like you’d do with a Python callable.

a = lambda {|x| puts x}
a.call(4) # works, and prints 4
a[4] # works and prints 4
a.(4) # same
a(4) # undefined method 'a' for main:Object

Why isn’t the last call possible? Will it ever be?

Answer 1

AFAIK it’s because ruby doesn’t let you define the () method for an object. The reason it doesn’t let you define the () method is probably due to the fact that parentheses are optional in method calls.

And for what it’s worth, here’s a hack to let you invoke lambdas using () http://github.com/coderrr/parenthesis_hacks/blob/master/lib/lambda.rb