gistfile1.rb

# tail.rb
# JAVA_OPTS="-Djruby.tailcall.enabled=true" jruby tail.rb --1.9
# Error: Your application used more stack memory than the safety cap of 1024k.
#   Specify -J-Xss####k to increase it (#### = cap size in KB).
# Specify -w for full StackOverflowError stack trace

def fact(n, acc)
  if n == 0
    acc
  else
    fact n-1, n*acc
  end
end

p fact(25000, 1)