fizzbuzz_stand_alone

#!/usr/bin/env sed -f ./fizzbuzz_stand_alone

# change this number:
#☃️100

/^#☃️/!d

s/^#☃️//

s/^0*//

# error
/^[1-9][0-9]*$/!{
c\
Error: input must be positive integer\
Usage: ./FizzBuzz_stand_alone
q
}

# begin
# n = 1
s/$/\
1/

# main
: m

# speeding up
/^[0-9]*\(\(\n[0-9BFiuz]*\)\{15\}\)\n[0-9]*$/{
  h
  s//\1/; s/.//; p; s/.*//
  x
  s/\n.*\(\n\)/\1/
}

s/\n[0-9]*$/&&/

# FizzBuzz
# if n % 3 == 0
/^[0-9]*\(\(\n[0-9BFiuz]*\)\{3\}\)*\n[0-9]*$/s/[0-9]*\(\n[0-9]*\)$/Fizz\1/
# if n % 5 == 0
/^[0-9]*\(\(\n[0-9BFiuz]*\)\{5\}\)*\n[0-9]*$/s/[0-9]*\([Fiz]*\)\(\n[0-9]*\)$/\1Buzz\2/

# end
/^\([0-9]*\)\n\(.*\)\n\1$/{
  s//\2/
  q
}

# suc
# n++
: s
s/.X/&0123456789YC/
/X/!s/$/X0123456789YC/
s/\(.\)X.*\1\(.\).*C/\2/
s/Y/X0/
/\nX/s/X/1/
/X/b s

b m