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Ruby block parameter names

Does anyone know if there is a way to access the parameter names passed in ruby ​​blocks?

eg.

def do_something()
  # method uses the names of the parameters passed to the block
  # in addition to their values
  # e.g. the strings "i" and "j"
end

do_something { |i, j| ... }

This is a requirement for dsl I am writing and a rather unusual use case. Maybe this is possible with something like parsetree, I was just wondering if there was an easier / leaner way.

thanks

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2 answers


This is indeed possible, but only in trunk version 1.9:

->(a,b,c) {}.parameters


It has not been released and will most likely be included in Ruby 1.9.2.

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update . It looks like Ruby 1.9 can do what you ask. See Florian's answer.

Yes, well, Ruby has a great facility for passing named parameters: Hash.

This is how it works:



def do_something(params)
  params.each do |key, value|
    puts "received parameter #{key} with value #{value}"
  end
end

do_something(:i => 1, :j => 2)

Otherwise, there is no way to get past variable names in Ruby. A variable in Ruby is just a reference to an object, so there is no way to find out from the object whose reference (potentially many references) was used in the method call.

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