Calling a Function From a String With the Function's Name in Ruby

Question

How can I do what they are talking about here, but in Ruby?

How would you do the function on an object? and how would you do a global function (see jetxee's answer on the post mentioned)?

EXAMPLE CODE:

event_name = "load"

def load()
  puts "load() function was executed."
end

def row_changed()
  puts "row_changed() function was executed."
end 

#something here to see that event_name = "load" and run load()

UPDATE: How do you get to the global methods? or my global functions?

I tried this additional line

puts methods

and load and row_change where not listed.

Answer 1

Personally I would setup a hash to function references and then use the string as an index to the hash. You then call the function reference with it's parameters. This has the advantage of not allowing the wrong string to call something you don't want to call. The other way is to basically eval the string. Do not do this.

PS don't be lazy and actually type out your whole question, instead of linking to something.

Answer 2

To call functions directly on an object

a = [2, 2, 3]
a.send("length")

which returns 3 as expected

or for a module function

FileUtils.send('pwd')

and a locally defined method

def load()
    puts "load() function was executed."
end

send('load')

Answer 3

Use this:

> a = "my_string"
> meth = a.method("size")
> meth.call() # call the size method
=> 9

Simple, right?

As for the global, I think the Ruby way would be to search it using the methods method.

Answer 4

I have covered several ways for Ruby's dynamic method calling in the past. Have a look at them.