transform options to or string #bash

bla.md

$ ./bla.sh 'y[es], n[o], v[iew], c[ancel], [al]l'
all|c|cancel|l|n|no|v|view|y|yes

bla.sh

#!/usr/bin/env bash

smth_checks()
{
  typeset -a elements
  typeset IFS=","
  if [[ -n "${ZSH_VERSION:-}" ]]
  then elements=( ${=1// /} )
  else elements=( ${1// /} )
  fi
  for el in "${elements[@]}"
  do
    echo "${el//\[*\]/}"
    echo "${el//[\[\]]/}"
  done | sort -u
}

smth_check()
{
  typeset IFS=$'\n'
  typeset -a elements
  elements=( $(cat -) )
  IFS='|'
  __check="${elements[*]}"
}

smth()
{
  typeset __check
  smth_check < <( smth_checks "$1" )
  echo "${__check}"
}

smth "$@"