Live programming repl!

replit.zsh

function replit () {
  if [[ "$1" == "-h" ]] || [[ "$1" == "--help"  ]]; then
    echo "
    Usage:
      replit <lang>
      replit <...>
      replit (-h|--help)

    Description:
      Watch for changes in a file, and run a language against the file.

      If a file is not provided, a temporary file is created.
    " | awk 'sub(/^.{4}/,"")'
    return 0
  fi

  lang="$1"
  file="$2"

  if [ -z "$lang" ]; then
    echo "replit: please specify a language executable to use as a first parameter"
    return 1
  fi

  if ! command -v entr &> /dev/null; then
    echo "the command 'entr' must be installed for this to work! See https://eradman.com/entrproject/"
    return 1
  fi

  if ! command -v code &> /dev/null; then
    echo "the command 'code' must be installed for this to work! See https://code.visualstudio.com/"
    return 1
  fi

  if [ -z "$file" ]; then
    # -- launching a shell repl against a temp file
    input=$(mktemp)
    trap 'echo "💻 closing repl..." && rm -f "$input"' EXIT

    echo "$input"

    (code "$input" &)

    echo "💻 launching live-$lang. Press q to quit, <space> to force-rerun. Save code in your file to run it!"
    echo "$input" | entr -r "$lang" $input
  else
    # -- let people provide whataver launch options they want to to their language

    trap 'echo "💻 closing repl..."' EXIT

    (code "$input" &)

    echo "💻 launching live-$lang. Press q to quit, <space> to force-rerun. Save code in your file to run it!"
    echo "$input" | entr -r "$@"
  fi
}