An implementation of Python's formatted strings in pure Ruby

f.rb

require "bundler/inline"

gemfile do
  gem "binding_of_caller"
end

require "binding_of_caller"

module Kernel
  def f(template, vars = binding.of_caller(1))
    template.gsub(/\{.+\}/) { vars.eval(_1[1..-2]) }
  end
end

name = "foo"
print(f"hello {name}")
print(f"{f\"{6+7}\"}")

##
# hello foo
# 13