Add toml wrangling functionality

# {{{ utilities

function tomlsh {

  python3 - "$@" <<EOF

#! /usr/bin/env python3

import argparse

import sys

import toml

def resolve_dotted_name(data, dotted_name):

    components = dotted_name.split(".")

    for comp in components:

        data = data.get(comp)

        if data is None:

            return data

    return data

def has_key(data, args):

    return 0 if resolve_dotted_name(data, args.dotted_name) is not None else 1

def get(data, args):

    data = resolve_dotted_name(data, args.dotted_name)

    if data:

        print(data)

    return 0

def get_list(data, args):

    for item in resolve_dotted_name(data, args.dotted_name):

        print(item)

    return 0

def main():

    parser = argparse.ArgumentParser(description="TOML wrangling for shell scripts")

    parser.add_argument("filename", default="FILE.TOML")

    subp = parser.add_subparsers()

    parser_has_key = subp.add_parser("has-key")

    parser_has_key.add_argument("dotted_name", default="DOTTED.NAME")

    parser_has_key.set_defaults(func=has_key)

    parser_get = subp.add_parser("get")

    parser_get.add_argument("dotted_name", default="DOTTED.NAME")

    parser_get.set_defaults(func=get)

    parser_get_list = subp.add_parser("get-list")

    parser_get_list .add_argument("dotted_name", default="DOTTED.NAME")

    parser_get_list .set_defaults(func=get_list)

    args = parser.parse_args()

    if not hasattr(args, "func"):

        parser.print_usage()

        sys.exit(1)

    data = toml.load(args.filename)

    sys.exit(args.func(data, args))

if __name__ == "__main__":

    main()

EOF

}

function with_echo()

{

  echo "+++" "$@"