Ruby dynamic method calling

I’m pretty sure that you have heard lots about ruby, specially as being a dynamic language, you can create methods on the fly, add instance variables, define constants and invoke existing methods dynamically , and that’s what this post is all about.

As you know in ruby you can call a public instance method directly ,ex :

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s= "hi man"
p s.length #=> 6
p s.include? "hi" #=> true

One way to invoke a method dynamically in ruby is to send a message to the object :

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p s.send(:length) #=> 6
p s.send(:include?,"hi") #=> true

A second way is instantiate a method object and then call it:

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method_object = s.method(:length) 
p method_object.call #=> 6
method_object = s.method(:include?)
p method_object.call('hi')  #=> true

And the third way is to use the eval method:

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eval "s.length" #=> 6
eval "s.include? 'hi'" #=>true

Well, when to use what?

Ruby dynamic method calling – Khelll's Blog