Ruby parens-free function calls [was Re: Accessing parent objects]

[Chris Angelico]

On Tue, Mar 27, 2018 at 11:00 PM, Rick Johnson
<rantingrickjohnson at gmail.com> wrote:
> On Tuesday, March 27, 2018 at 1:55:01 AM UTC-5, Gregory Ewing wrote:
>> Chris Angelico wrote:
>> > Question: How do you get a reference to a Ruby function? Or are they
>> > not first-class objects?
>>
>> They're not first-class. So, you can't.
>
> If Chris means: "how do you get a reference to a Ruby
> function object", then yes, it _is_ possible! Consider the
> following:
>
>     ## Ruby 1.9 ##
>     rb> def print_name(name); puts "Your name is #{name.inspect}"; end
>     rb> print_name("Chris")
>     "Chris"
>
> In this case, since the function `print-name` was defined
> outside of an class definition, Ruby will add the function
> as a method of `Object` (Ruby is more purist about OOP than
> Python). So, to get a reference to the function object
> (which is now a method of `Object`!), all we need to do is
> call a method named "method" ("gigity") and pass it the name
> of the method as a string:
>
>     rb> Object.method("print_name")
>     #<Method: Class(Object)#print_name>
>     rb> Object.method("print_name").call("Meathead")
>     Your name is "Meathead"
>
> PS: Greg, please inform Chris that Google is his friend. ;-)

Cool, so Greg was right: you can't get a reference to a method or
function. You need magic to simulate it.

ChrisA