Macro ezcli::flag

macro_rules! flag {
    (-$short_name:tt) => { ... };
    (--$long_name:tt) => { ... };
    (let -$short_name:tt) => { ... };
    (let --$long_name:tt) => { ... };
    (-$short_name:tt, --$long_name:tt) => { ... };
    (-$short_name:tt, $args:ident) => { ... };
    (--$long_name:tt, $args:ident) => { ... };
    (let -$short_name:tt, $args:ident) => { ... };
    (let --$long_name:tt, $args:ident) => { ... };
    (-$short_name:tt, --$long_name:tt, $args:ident) => { ... };
}

Command line argument flag for on/off state.

Uses std::env:args() to determine the arguments passed to the program. If there is an argument matching the flag’s name then this variable will be truthy. There are two flag types that are often passed in cli arguments: short-name form (-f) and long-name form (–flag). This macro replaces underscores in long-name argument token with hyphens (e.g.: flag!(--my_boolean) -> "--my-boolean").

use ezcli::flag;
// args: "-b --my-boolean"

// accepts "-b" (short-name form)
// if passed in, this expression is true
flag!(-b);
// accepts "--my_boolean" (long-name form)
// if passed in, this expression is true
flag!(--my_boolean);

---

Use the keyword let before the argument to create a variable with the same name as the argument.

use ezcli::flag;

// Creates a variable named after the flag
flag!(let --my_boolean);

---

You can use both short-name (-f) and long-name forms (–flag) together by separating them with a comma.

use ezcli::flag;

flag!(-b, --my_boolean);
let bool_var = flag!(-b, --my_boolean);

---

In some case of not wanting to use the program’s environment arguments using a slice is also possible.

use ezcli::flag;

let args = ["--my_boolean"];
flag!(--my_boolean, args);

---

Flag groups can be used with short-name flags

use ezcli::flag;

let args = ["-abc"];
flag!(-a, args);
flag!(-b, args);