HOWTO: autocompletion in a bash function/alias

.bashrc

# I have a function called as shocker which 'sh-es' into a docker container
# to enable autocompletion in the command, I do the following
# `complete -F __docker_complete_container_names shocker`

# __docker_complete_container_names is a function available in /etc/bash_completion.d/docker
# the above file is available at https://docs.docker.com/machine/completion/

# the __docker_complete_container_names function does something like the following
# COMPREPLY=( $(compgen -W "(list of containers)" -- "$cur") )
# documentaton : http://www.tldp.org/LDP/abs/html/tabexpansion.html
# WHERE : $cur is the current value of the cursor that should be autocompleted 
# 
# To check the function already available on your terminal, run the command
# `typeset -F` - i'd grep it with what i want
# `typeset -F | grep -i git` 
# NOTE : These are all functions available, all of they may not be for autocompletion
# For git: check https://github.com/git/git/blob/master/contrib/completion/git-completion.bash


#
# docker exec sh on the application
#
# complete adds autocompletion
# expects docker available in /etc/bash_completion.d
# https://docs.docker.com/machine/completion/
complete -F __docker_complete_container_names shocker
shocker() {
  docker exec -it $1 sh
}