Crate easy_arg

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§EasyArg

EasyArg parse args from command line arguments/system envrioment/.env files

§You will read:

  • how to set
  • how to get
  • how to alias
  • how to add help description

§How to set

§1.Command line:

your_app -p --name=some_one -- invalid --hello "world"

will produce:

{
    "name": "some_one",
    "hello": "world",
    "p": "true",
}

rule:

--p = "abc" ✔
--p=abc     ✔
--p abc     ✔
--p -- abc  ✔ // p = "abc",-- will be ignored
-p          ✔ // p = "true"
-p=abc      ✔
--p         ❌

§2.system envrironment variable

export SOME_VAR=123

Then you can access it by:

let easy = EasyArg::new();
easy.get_string("SOME_VAR") // "123"

§3..env files

You can use .env file in diffrent ways:

  • pass -e/--envfile/-envfile args

If no envfile args, it will search (in order):

  1. current_working_directory/.env
  2. current_working_directory/.easy_arg.env
  3. home_directory/.easy_arg.env
§If you want to customize the .env filename, use
EasyArg::new_with_env("your_file_name");

It will search:

  • current_working_directory/your_file_name.env
  • home_directory/your_file_name.env

.env example:

(docs.rs couldn’t display .env code properly, read it on crates.io)

DIR = abc
DIR2="dfdadfasfasf" # this is a comment

will produce

{
    "OK": "true",
    "DIR": "abc",
    "DIR2": "dfdadfasfasf",
    "HHD": "/home/xxx/abc/${NOT_EXIST}",
    "GOOD": "true",
}

§How to get

Note: All variables will be parsed to string.

easy represents an instance of EasyArg.

§1. You need the raw string

easy.raw_value("KEY");

§2. You need a string, event it doesn’t exist

easy.get_string("KEY");

§3. panic if the string doesn’t exist

easy.must_get_string("IMPORTANT_KEY");

§4. You need bool value

if you didn’t provid a value for the key, it defaults to true. Only "false","False","FALSE","0","null","NULL","Null" will be parsed to false.

easy.get_bool("KEY");

§5. You need a vec

// --list=a,b,c
easy.get_vec("KEY") // the result: vec!["a", "b", "c"]

§How to alias

your_app -p --s=xbox

your rust code

easy.alias("p", "PS5")

easy.to_string("PS5") // "true"
easy.to_string("p") // "true"

§How to add help description

easy.desc_str("a", "description")
easy.desc_flag("b", "description")

output:

Executable: target/debug/xxx
-- a           description
- b           description

Structs§

EasyArg
Section

Enums§

ArgType

Functions§

load_env
read key/value from .env file
to_bool