countries.csv

load_countries.cr

require "csv"

filename = ARGV[0]

# This reads the CSV and prints a Hash literal to the output
puts "{"
CSV.each_row(File.read(filename)) do |row|
  print row[0].inspect
  print " =>"
  print row[1].inspect
  puts ","
end
puts "}"

main.cr

# This runs the load_countries program at compile time with "countries.csv"
# as an argument. The result of that execution is a hash literal:
# we paste it in the program (with {{ ... }})
countries = {{ run("./load_countries", "./countries.csv") }}
p countries