Derive Macro from_attr::FromAttr

#[derive(FromAttr)]
{
    // Attributes available to this derive:
    #[attribute]
}

Generate an implementation of FromAttr trait.

Example

use from_attr::FromAttr;
use syn::{parse_quote, Expr, LitStr, Type};

#[derive(FromAttr)]
#[attribute(idents = [test])]
struct Test {
    a: LitStr,
    b: Option<String>,
    c: Type,
    d: Expr,
    e: Vec<Type>,
    f: bool,
    g: bool,
}

let attrs = [
    parse_quote!(#[test(a = "a", b = "b", c = (), d = if true { "a" } else { "b" }, e = [(), Debug], f)]),
];

assert_eq!(attrs.len(), 1);
let test = Test::from_attributes(&attrs).unwrap().unwrap().value;
assert_eq!(attrs.len(), 1);

assert_eq!(test.a.value(), "a");
assert_eq!(test.b.unwrap(), "b");
assert!(matches!(test.c, Type::Tuple(_)));
assert!(matches!(test.d, Expr::If(_)));
assert!(test.e.len() == 2);
assert!(test.f);
assert!(!test.g);

Attribute arguments

#[attribute]: used on struct

Name	Type	Example	Optional	Default	Description
idents	Vec<syn::Ident>	idents = [test]	No	-	Idents of the attribute.

#[attribute]: used on field

Name	Type	Example	Optional	Default	Flag	Description
rename	Option<String>	rename = "type"	Yes	None	-	Rename the field.
default	FlagOrValue<syn::Expr>	default default = true	Yes	FlagOrValue::None	core::default::Default::default()	Default field value.
conflicts	Vec<syn::Ident>	conflicts = [a, b, c]	Yes	Vec::new()	-	Conflicts fields.