dynamic_call_bench.rb

#!/usr/bin/env ruby
#frozen-string-literal: true

require 'benchmark'

chain = [ 'to_i', 'zero?' ]

CALLS = 1_000_000
var = 123

Benchmark.bm(10) do |x|
  x.report 'inject' do
    CALLS.times do
      chain.inject(var){|val, meth| val.public_send(meth)}
    end
  end

  x.report 'eval' do
    f = eval("->(val){ val.#{chain.join '.'} }")
    CALLS.times{ f.call(var) }
  end
end

results

                 user     system      total        real
inject       0.460000   0.000000   0.460000 (  0.464011)
eval         0.090000   0.000000   0.090000 (  0.091068) #=> ~5.1x faster

CPU: i5-6600K (4x3.5 GHz)